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Max-Planck-Institut
für Plasmaphysik
EURATOM Association
Annual Report 2004
1_Umschlag.qxp
Max-Planck-Institut
für Plasmaphysik
Annual Report 2004
False colour pictures of a tangential view into WENDELSTEIN 7-AS vacuum vessel showing magnetic field lines made visible
by the interaction of an accelerated electron beam in a highly diluted hydrogen gas.
Left: magnetic configuration with ι/2π≈5/9
Right: magnetic configuration with ι/2π≈2/5
Max-Planck-Institut
für Plasmaphysik
EURATOM Association
Annual Report 2004
The Max-Planck-Institut für Plasmaphysik is an institute of
the Max Planck Gesellschaft, part of the European Fusion
Programme (Euratom) and an associate member of the
Helmholtz-Gemeinschaft Deutscher Forschungszentren.
2005-2006. As in the preceding period,
The past year at the Max-Planckone of the task force leaders comes
Institut für Plasmaphysik (IPP) has
from another EU Association, highbeen marked by change. The structure
lighting the substantial contribution of
of the Wendelstein 7-X project was
our sister organisations in the Euroadjusted to the approaching personnelpean fusion programme to the ASDEX
intensive assembly phase. Five subUpgrade programme under the new
divisons were formed: Project Co-ordi“Europeanized” structure.
nation, System Engineering, Basic
Machine, Assembly and Physics.
The engineering staff of the Wendel
Wendelstein 7-X is being constructed in
stein 7-X project has been substantialorder to demonstrate that the stellarator
ly increased. In addition, FZJ and FZK
is a viable option for a demonstration
are contributing to diagnostics, the
Alexander M. Bradshaw
fusion power plant. Two years after
bus-bar system and ECRH. Co-operashutdown (in July 2002) it is also pleastion, in particular with the CEA, was
ing to still be able to report good scientific results from the predecessor experiment, Wendelstein also extended. The module assembly was started with the
7-AS. Flux surface measurements have been successfully mounting of saddle-coils and thermal insulation over the
carried out and agree well with the original ones. For the first vessel sector. A rather elegant technical solution has
first time they were performed at full field, showing a reduc- been developed with industry for the complex 3-dimensional thermal insulation. The delivery of ports and the develoption of the rotational transform by about two per cent.
ment of the infrastructure continued according to plan. Five
The programme of the ASDEX Upgrade tokamak ranges non-planar and four planar coils have been tested under
from clarifying first-principles questions in plasma physics cryogenic conditions. They all passed the test at nominal
to detailed preparation of operational scenarios for ITER. current. The quench temperature was higher than anticipatConcerning the latter, we have further extended the parame- ed, thus adding some additional operational margin. The
ter space for operation in the “improved H-mode” regime second ECRH gyrotron is in routine operation. Design repreviously discovered on ASDEX Upgrade. This mode had views of the major components have been carried out with
already been shown to be a candidate for prolonging the international participation.
ITER pulse length at constant fusion power, since it allows
operation at reduced plasma current. This mode of operation IPP physicists have contributed substantially to the experipromises to increase the fusion power yield of ITER if run at mental campaigns C13 and C14 at JET. In March the major
the nominal ITER plasma current. Similar results have since Enhanced Performance (EP) shutdown commenced in order
been achieved on the JET and DIII-D tokamaks in close col- to prepare installation of an ITER-like ICRH antenna as a
laboration with IPP staff. The studies on tungsten as an alter- means of improving the power handling of the divertor and
native first-wall material with the potential to minimize the increasing the neutral beam power. New diagnostics will be
tritium inventory in the wall of future nuclear fusion devices installed. IPP physicists have served as task force leader, or
were continued. Operation with a large fraction of the device led an enhancement project, or joined the Close Support
interior, including the upper divertor, covered with tungsten Unit or the operator on the basis of long-term secondments.
encountered no major problems. We will continue on the
route to an all-tungsten first wall in order validate the On behalf of the Directorate and the Board of Scientific
approach for ITER and beyond. Another highlight in 2004 Directors I would like to take this opportunity of thanking
was the development of a first-principles theory based the Greifswald staff for their dedication, commitment and
understanding of the turbulent processes governing the den- patience despite the various technical problems and the projsity profile in tokamak discharges. It was found that differ- ect re-organisation at the beginning of 2004. We wish them
ent turbulent processes (ITG and TEM) can dominate under every success in the beginning assembly phase. Moreover,
different experimental conditions, thus explaining the we are also indebted to the Garching staff for their support
observed variability of the density profile (as opposed to the for the Wendelstein 7-X project, in particular to those who
rather stiff temperature profiles). At the end of 2004, a new have been prepared to relocate to Greifswald, and of course,
task force structure was established for the organization of as every year, for the excellent research results obtained in
the physics programme on ASDEX Upgrade in the period all the Divisions.
III
Content
Tokamak Research
University Contributions to IPP Programme
ASDEX Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
JET Co-operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
University of Augsburg
Lehrstuhl für Experimentelle Plasmaphysik . . . . . . . . . . . .101
University of Bayreuth
Lehrstuhl für Experimentalphysik III . . . . . . . . . . . . . . . . . . .103
University of Berlin
Lehrstuhl für Plasmaphysik . . . . . . . . . . . . . . . . . . . . . . . . . .105
University of Kiel
Lehrstuhl für Experimentelle Plasmaphysik . . . . . . . . . . . .107
Technical University of München
Real-time speckle metrology for surface diagnostics . . . . .109
University of Stuttgart
Institut für Plasmaforschung (IPF) . . . . . . . . . . . . . . . . . . . .111
Stellarator Research
WENDELSTEIN 7-X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
WENDELSTEIN 7-X Applied Theory . . . . . . . . . . . . . . . . . . . .47
WENDELSTEIN 7-AS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
WEGA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
ITER
ITER Co-operation Project . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Publications
Fusion Technology
Publications und Conference Reports . . . . . . . . . . . . . . . . .119
Lectures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143
Laboratory Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168
Teams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
Plasma-facing Materials and Components . . . . . . . . . . . . . . .63
Energy and System Studies . . . . . . . . . . . . . . . . . . . . . . . . . .69
Plasma Theory
Appendix
Theoretical Plasma Physics . . . . . . . . . . . . . . . . . . . . . . . . . . .73
How to reach IPP in Garching . . . . . . . . . . . . . . . . . . . . . . . .172
How to reach Greifswald Branch Institute of IPP . . . . . . . . .173
Organisational structure of
Max-Planck-Institut für Plasmaphysik (IPP) . . . . . . . . . . . . .174
Basic Plasma Physics
Centre for Interdisciplinary Plasma Science . . . . . . . . . . . . .85
VINETA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Electron Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
Infrastructure
Computer Center Garching . . . . . . . . . . . . . . . . . . . . . . . . . . .95
V
Tokamak Research
ASDEX Upgrade
Head: Dr. Otto Gruber
1 Overview
The main aim is preparing the physics base of
ITER. Significant progress has been made in
operating with tungsten-clad walls, understanding of transport and impurity control, the ELM
mitigation by frequency control, and the control of performance limiting instabilities. The
H-mode operation was extended into the required parameter ranges and towards an integrated scenario extrapolating to an improvement in nTt or the inductive pulse length.
Agreements. In summary, the
AUG programme is embedded
in a framework of national (see
section on University contributions to IPP programme) and
international collaborations (see
section 10 on International Cooperation).
The AUG Programme Committee
enables the EURATOM Associations to take more responsibility for our programme. This
body defines the Task Forces responsible for the different
elements of our programme, nominates the Task Force
Leaders and approves the experimental programme.
Furthermore, the bodies that work out the programme proposals are open to external participants, and remote participation in the meetings is used. For the 2004 campaign 175
proposals were received including 37 proposals from outside IPP. With this structure, we have achieved a compromise between the increased European participation and the
flexibility that has so far been typical for the AUG programme.
During the 2004 experimental campaign from mid December 2003 until the end of July 2004, AUG was operated in 78 shifts with about 1400 pulses of technical tests,
diagnostic calibrations and plasma discharges. The flexible
heating systems consist of the neutral beam heating (NBI)
which delivered powers up to 20 MW and the ion cyclotron
resonance system (ICRH), which is capable of routinely
coupling up to 5 MW in ELMing H-mode discharges. Even
7 MW can be launched after some conditioning discharges.
These two heating methods are used to separate the effects
of heat, particle and momentum deposition on energy and
particle transport, MHD stability, fast particle effects and
driven currents. The present electron cyclotron resonance
system, the third heating element, was kept available up to a
coupled power of 1.6 MW allowing pure electron heating
(ECRH) and current drive (ECCD), electron transport studies and MHD mode control of sawteeth and neo-classical
tearing modes (NTM). Both RF systems allow the control of
particle and impurity transport via the heat deposition profile. Provisions for current drive and for active control of
current profiles in advanced scenarios were available with
more perpendicular on-axis or off-axis tangential NBI and
ECRF using steerable mirrors. Stationary discharges with
up to 10 s flat-top allowed steady state investigations not
only on the transport and MHD time scales but also for up to
10 current diffusion times, still a unique feature for tokamaks with ITER plasma geometry. The operation regarded
the hardware upgrades from 2003, essentially the extension
of the tungsten coated first wall area by 14 m2 to 65 % of the
first wall area including the upper divertor targets allowing
1.1 Scientific Aims and
Operation
The tokamak fusion experiment
ASDEX Upgrade (AUG) went
into operation in 1991 after
nearly 10 years of planning, design and construction. The
ASDEX Upgrade design combines the successful divertor
concept with the requirements
of a next step fusion reactor, in particular the need for an
elongated plasma shape and poloidal magnetic field coils
outside the toroidal magnetic field coils. AUG is close to
ITER in its magnetic and divertor geometry and in particular
the relative length of both divertor legs compared with the
plasma dimensions. The installed heating power of up to
28 MW ensures that the energy fluxes through the plasma
boundary are equivalent to those in ITER. The scientific
programme gives priority to the preparation of the design
(heating, fuelling, first wall materials), physics basis and
discharge scenarios of ITER and to the exploration of
regimes beyond the ITER baseline scenario. The studies
were guided by five Task Forces (TF) consisting of
– Confinement and performance of the ITER base-line scenario, the ELMy H-mode, and improved H-mode scenarios leading to enhanced performance and longer inductive
pulse lengths,
– Scenarios and physics of advanced tokamak plasma concepts with both internal transport barriers (ITB) and mainly non-inductive current drive,
– H-mode pedestal physics and ELM mitigation and control,
– Magnetohydrodynamic (MHD) stability, active stabilisation of β limiting instabilities as well as avoidance and
mitigation of disruptions,
– Scrape-off layer and divertor physics with the aim of optimising power exhaust and particle control (ash removal)
and optimisation of first wall material with emphasis on
tungsten.
The similarity of ASDEX Upgrade to ITER makes it particularly suited to testing control strategies for shape, plasma
performance and MHD modes. The similarity in cross-section to other divertor tokamaks is important in determining
size scalings for core and edge physics. In particular, the
physics programme of 2004 was based on the conclusions
and findings of the last years, new ITER requirements and
tokamak concept improvement. Our programme largely covered the “High Priority Physics Research Areas” provided
by the ITPA Coordinating Committee. Several items have
been further investigated in joint experiments at all major
tokamaks as proposed by the ITPA Topical Groups and
approved in the framework of the IEA Implementing
3
ASDEX Upgrade
the comparison of a tungsten (top) and graphite (bottom)
divertor, the low field side (LFS) entrance regions of the
lower divertor and one LFS poloidal limiter.
nical systems. A new fast control and data acquisition system is under development and was tested in several steps in
2004. After implementation of remaining protection and
performance control algorithms it will be fully operational
at the beginning of 2005. The step-by-step transition from a
graphite to a tungsten device has the highest priority in the
present AUG hardware extension programme. As prototypes
one ICRH protection limiter (out of 8) and one guard limiter
(out of 4) were covered with 200 µm tungsten in the 2004
shutdown lasting from August until mid December. These
LFS limiters show the highest erosion due to orbits from
beam injected high-energy particles (see section 4). Only the
other LFS limiters and the lower divertor tiles will remain as
graphite surfaces in the next campaign. Until the end of
2006 all surroundings should be covered with tungsten. In
addition the LFS targets of the bottom divertor were hardened to sustain higher temperatures, as broken tiles have
led to vessel openings in 2004. The pellet ELM-triggering
capability will be extended to higher frequencies and smaller pellets by a new blower gun. The upgrading of the ECRF
power to 4 gyrotrons each of 1 MW/10 s pulse length at
tuneable frequencies between 105 and 140 GHz is underway
together with the installation of on-line steerable launchers
for feedback of the deposition location.
In the mid term range we will focus even more on advanced
tokamak operation as the hybrid scenario, the improved Hmode, and the ITB discharges with reversed magnetic shear.
Reliable creation and sustainment of optimal shear profiles
require an additional current profile control method as
LHCD with about 5 MW installed power. In order to overcome the lower ideal MHD limits of reversed shear plasmas
we have to rely on wall stabilization, which needs a stabilizing shell at the low field side much closer to the plasma than
the present walls. An MHD stability study using full 3dgeometry and including the need of diagnostic and heating
access demands for a shell location at a distance of 20 % of
the plasma minor radius. This shell has to be combined with
internal coils to actively control the MHD instabilities growing on the resistive time scale of the shell (RWMs). As such
internal coils have several other interesting applications,
such as rotation control, ELM tailoring and tearing mode
control, their installation as a first step of the package might
be desirable.
The programme in 2005 will be executed in co-operation
with the EU Associations and in close connection with the
JET programme and the ITPA joint experiments. To streamline the AUG programme the number of task forces was
reduced to four: improvement of H-mode and integrated
scenarios; pedestal physics including tolerable ELMs; SOL
and divertor physics and first wall materials; MHD instabilities and their active control. The strong European participation in the scientific exploitation of AUG is reflected by the
appointment of the task force leader for MHD from another
1.2 Main results in 2004
During 2004 we have demonstrated the robustness of our
”improved H-mode”, which now forms the basis of the long
pulse ITER hybrid scenario, establishing it over a broad
range of conditions: moderately peaked electron density
profiles ranging from n=nGW down to values corresponding
to the ITER collisionality, heating scenarios which achieve
Te=Ti, q95 values down to 3, βN values of at least 3 (with
only benign MHD-activity), bootstrap fractions up to 50 %,
and the ρ∗ range accessible within a factor of 2. All results
were obtained with a predominantly tungsten-clad first wall
without performance affecting impurity behaviour. At nearGreenwald densities these discharges show well-tolerable
type-II ELMs. The maximum performance parameters
obtained would allow ITER operation either at 50 %
increased H98(y,2)βN /q952 (∝Q), or the ITER design value at a
30 % reduced plasma current allowing long inductive pulse
lengths well above 1000 s.
For active control of discharges we have refined our diagnostic systems (particularly in the plasma edge region),
improved the physics understanding (particularly of particle
transport) and developed suitable actuators. In the presence
of high-Z plasma facing components the W concentration
could be kept below 10-5 avoiding both the influx of impurities through the edge barrier and the tendency for ELM-free
phases as well as the central impurity peaking in the presence of peaked hydrogen density profiles. The former has
been achieved by ELM control through pellet pace-making
or vertical wobbling. Central electron heating was found
effective to counteract impurity accumulation by affecting
plasma density profiles and impurity diffusion. Progress
was made in the understanding of anomalous transport
showing a multi-faceted picture of mode dominance in different plasma parameter regimes of ITG, TEM and ETG turbulence, but an agreement of experiments and theory was
found extending over a broad range of these conditions. In
the absence of natural radiators (e.g. C) impurity seeding
was shown to result in tolerable target power loads. In the
area of direct NTM control we have optimised the efficiency
of stabilisation by DC-ECCD through variation of the
launching angle and increased thereby the stabilised βN. Offaxis NBI current drive shows a toroidal current profile modification, which is strongly reduced at higher input powers
especially at low triangularity configurations.
1.3 Technical Enhancements and Programme in 2005
In order to achieve the consolidation of the ITER design, its
base line scenario and the exploration of new improved scenarios, it is necessary to successively upgrade the AUG tech4
ASDEX Upgrade
EURATOM Association as before. Out of the 147 submitted
proposals were 39 from 14 EURATOM Associates, a similar
level as for 2004. After prioritising and clustering of the proposals, the 2005 programme was approved by the ASDEX
Upgrade Programme Committee in December. The experimental effort of ASDEX Upgrade in 2005 is mainly
focussed on the development of consistent high performance scenarios operating with a tungsten wall and a suite of
control tools to access and stabilise these regimes.
In this annual report, sections 2-6 are concerned with current profile modifications using off-axis tangential NBI, stationary improved H-modes, the tungsten programme, impurity transport and control and diagnostic enhancements. In
section 7 the ASDEX Upgrade technical, heating and
CODAC systems are described. Section 8 deals with core
plasma physics, namely transport, active ELM control,
NTM physics, TAE modes, ITB collapses and zonal flows.
Section 9 covers edge, SOL and divertor physics, as edge
pedestal profiles, wall heat loads, ELM physics, edge transport, chemical erosion and carbon migration. Section 10
describes the international co-operations of AUG.
Figure 1: Comparison of the predicted (red) and measured (black) relative
changes in the current driven by the Ohmic transformer between discharge
phases of on- and off-axis NBI. Discharge conditions: Bt=2.5T, Ip=800 kA,
δ=0.15. PNBI=5 MW.
significantly smaller than the predicted ones: especially at
low densities/high temperatures, with the discrepancy reaching up to a factor of 3. Even at these reduced efficiencies,
the remaining NBI current drive (e.g., ≥100 kA for
ne=4⋅1019 m-3) should, however, still suffice to give rise to
significant current profile modifications, particularly in situations where strong off-axis current drive is predicted.
According to the MSE measurements the q-profiles in the
on- and off-axis NBI phases coincide, however, within the
error bars. Obviously a re-distribution is taking place, either
of the current itself (e.g. by the observed (1,1) mode activity), or of the driver of the additional current, the fast ions.
To test the hypothesis of an MHD-like current re-distribution we have checked the influence of the q-profile and, in
particular, the role of the q=1 surface, varying q at the plasma edge between 4 and 6.2. We did not find any obvious
influence of qa within this range. The measured current drive
efficiency at the maximum value of qa with qa=6.2,
(Bt=2.5 T, Ip=600 kA) was comparable to that observed in
the 800 kA discharges, in spite of the larger influence of the
NBI driven current expected at the lower total current. In the
experiments with qa=4.7 (Bt=2.5 T, Ip=800 kA), marked by
black symbols in figure 1, some (1,1) mode activity was
observed. However, the q=1 radius in these discharges
(ρtor<0.1) appears, to be too small to cause a significant redistribution of driven current at about half the minor radius.
In the discharges with qa=6.2 no (1,1) activity was observed
at all.
A modification of the current profile caused by off-axis NBI
current drive was seen when the NBI power was reduced by
a factor of two (to 2.5 MW), at otherwise identical discharge
parameters (δ=0.15, Bt=2.5 T, Ip=800 kA). Although, due to
the reduced NBI power, the driven current predicted was
much smaller than in the former case (about 100 kA), a
significant shift in the q=1 surface and changes in the mea-
2 Current profile Modification with Neutral Beam Injection
ASDEX Upgrade is equipped with a flexible NBI heating
system, allowing not only on- and off-axis heating but also
off-axis current drive. Although in early experiments significant differences between the loop voltages in discharge
phases with on-axis heating and off-axis current drive configurations have been found, no evidence of changes in the
current profile was observed, in marked contrast to predictions of the ASTRA transport code. These observations were
based on MSE measurements and the localisation of MHD
modes, and extended over a sufficient time interval to
achieve stationarity in the current distribution (>2 s). They
have cast significant doubts on the feasibility of ITER scenarios involving current profile control by tangential, offaxis NBI injection.
In order to check if the amount of driven current agrees with
the predictions of classical slowing-down models we have
performed dedicated experiments, changing the beam distribution between on-axis heating and off-axis current drive. A
set of experiments was conducted in a low triangularity configuration, at a plasma current of 800 kA and with a total
NBI heating power of 5 MW. The measured and predicted
changes in the inductively driven current, caused by the
switch between the NBI sources, is shown in figure 1. The
experimental values have been derived from the loop voltages at the plasma edge during the on- and off-axis NBI
phases, respectively. To achieve stationary conditions also at
lower densities, we chose long phases of on-axis and offaxis NBI, to allow sufficient time for current profile relaxation (up to 5 s). The measured loop voltage changes are
5
ASDEX Upgrade
nario at q95≈ 3 or at the same performance with reduced plasma current and therefore longer pulses. The performance of a
discharge can be measured by the parameter βN·H98(y,2)/q952, a
common figure of merit for the fusion gain Q.
On ASDEX Upgrade such an advanced regime of stationary
operation with H98(y,2)~1.4 and βN>2.5, obtained simultaneously at q95~4, has been developed since 1998. It is called
“improved H-mode” and is characterized by a stationary qprofile with q0≥1, but typically close to 1, a low central
magnetic shear and the absence of sawteeth. Very similar
discharges were obtained in other tokamaks, e.g. DIII-D,
JET and JT-60U. An international collaboration, guided by
the recommendations of the ITPA, has started with the aim
to document the potential of this type of discharge for a long
pulse, high performance ITER operation – a “hybrid” of the
non-inductive, reversed shear scenario with internal transport barriers and the standard H-mode baseline scenario
with sawteeth and the usual monotonic q-profile (q0<1).
Access to the improved H-mode requires a q-profile with
q0≥1 and a low central magnetic shear to be created and
maintained. This is achieved by early, moderate heating during the current ramp and a subsequent step up of the heating power at the beginning of the current flat top, before q0
drops below 1. By doing this, sawteeth are avoided which
could trigger large amplitude neoclassical tearing modes
(NTM). During the high performance phases, fishbone
activity and/or small amplitude NTMs are generally observed which, however, hardly affect the energy confinement. This MHD activity is thought to play a role in keeping
the q-profile stationary with q0 close to 1. The specific
q-profile of improved H-modes may explain the observed
benign MHD behaviour since, for high plasma pressures, a
low magnetic shear at the (3,2) surface reduces the NTM
drive and, consequently, leads to a significantly smaller
amplitude of the (3,2) NTM. The maximum β attainable in
this scenario is determined by the occurrence of a (2,1)
mode that quickly locks and causes a strong reduction of
plasma pressure.
The existence domain of improved H-modes has been studied by performing scans in q95 and density. Stationary high
performance discharges with pulse lengths up to 40·τE or
more than twice the current diffusion time were achieved for
3.3≤q95≤4.3 in moderate density plasmas (ne/nGW~0.4) with
a collisionality, ν*, close to the ITER value. It has been
shown earlier that improved H-modes can be maintained up
to densities close to the Greenwald limit, i.e., high edge densities as required for power and particle exhaust in a reactor
are compatible with the improved H-mode regime. In order
to investigate a possible dependence on the normalized
Larmor radius, ρ*, discharges have been set up for which ρ*
is varied over the widest possible range under otherwise
similar parameters. No change in the achievable performance was observed.
sured MSE angles were observed, both in quite good agreement with ASTRA simulations. By increasing the plasma
triangularity, successful current profile modifications could
be extended even to the 5 MW level of off-axis NBI. At the
same discharge parameters as above (Bt=2.5 T, Ip=800 kA),
but at an increased triangularity of δ=0.4, we observed significant changes in the MSE angles and in the inferred
q-profile between the on- and off-axis NBI phases. Such a
q-profile modification is also consistent with the shift of the
q=1.5 surface determined from a small (3,2) NTM. The
observed changes in the MSE angles in this case are largely
consistent with ASTRA- code simulations. The application
of further central NBI heating power (+2.5 MW) to such discharges during all phases, also makes, however, the
observed current profile modification vanish in these high
triangularity cases.
The last experiment seems to rule out fast particle resonant
modes as the origin of spatial re-distribution of NB ions, as
the added beam has a different spatial and pitch angle distribution and a lower energy. For a more direct proof we have
modified the beam voltage of our current drive beams from
93 keV to 69 keV, bringing the deuterium ion velocity below
the Alfvén resonance at vA/3. At a comparable heating power
the results were virtually identical to those of the higher
voltage system.
To summarize, the experiments carried out with off-axis
NBI current drive show the re-distribution and a strong
reduction of the additional driven current at higher input
powers. Experiments at different qa, and the frequent
absence of measureable MHD activity appear to rule out a
dynamo-type re-arrangement of the magnetic field. We have
also established that the current re-distribution is more
closely connected to the passing heat flux than the local fast
particle energy density. This, together with the negative outcome of experiments with sub-vA/3 beam velocity, indicates
that a diffusive re-distribution of fast ions, driven by turbulent fluctuations correlated with the thermal transport, lies at
the origin of these observations. The improved performance,
at given current drive power, of the high triangularity discharges, in turn, is also in agreement with the observed trend
towards better energy confinement in the latter geometry.
3 The improved H-mode at ASDEX Upgrade
ELMy H-modes at high plasma current are foreseen as the
standard operation regime of ITER (15 MA at 5.7 T; q95=3).
A reference baseline scenario has been defined with a confinement factor compared to H-mode scaling of H98(y,2)=1 at a
normalized β value of βN=1.8 for which a fusion gain of
Q=10 is projected. Advanced scenarios aim at improving confinement and/or stability above the values given for the reference scenario. This would allow the operation of ITER either
at an improved performance compared to the reference sce6
ASDEX Upgrade
As a summary of the results obtained during the recent improved H-mode studies, the obtained performance in terms
of H98(y,2)·βN/q952 is plotted vs. (a/R)0.5·βp in figure 2. The latter quantity is a measure of the bootstrap current. Data are
taken for different time slices during the shots, also at low
heating power and with different heating methods. Clearly, a
high performance was achieved which exceeds the value
expected for the ITER baseline scenario for 3<q95≤4 and
reaches that value at q95∼4.5. For all q95 values, statio-nary
long pulses were obtained close to the maximum performance, limited only by the technically available pulse length.
For this type of discharge, (a/R)0.5·βp=1 roughly corresponds
to a bootstrap fraction of 40 %. At the higher q95 values, the
achievable bootstrap current can therefore signi-ficantly
contribute to the total current, a completely non-inductive
operation, however, is beyond the range covered by the
ASDEX Upgrade improved H-mode data.
Like in conventional H-modes heat transport in improved
H-modes is governed by the onset of turbulence above a critical value of ∇T/T, resulting in “stiff ” temperature profiles.
Improved H-mode discharges are, however, characterized by
stronger peaked density profiles compared to normal (sawtoothing) H-modes. This stronger density peaking is correlated with the lower collisionality due to the higher temperatures and it can explain to some extent the increase in
confinement factor. Like other discharges with peaked densities and no sawteeth, improved H-modes often suffer from
impurity accumulation. As discussed elsewhere in this
report, adding moderate amounts of central wave heating
was proven to be an effective tool for impurity control.
The experimental results discussed so far were obtained
with dominant NBI heating. This implies preferential ion
heating as well as input of momentum and particles, in contrast to α-heating in a reactor. Central wave heating is therefore more reactor relevant. Experiments have been started to
establish improved H-modes with dominant central ICRH
heating. In these shots, the NBI power was feedback controlled to keep βpol at a preset value while the RF power was
increased in several steps up to the maximum available
power (~6 MW). An example is given in figure 3. For the
discharge shown a stationary value of βN=2.6 was maintained with H98(y,2)~1.2. Over a period of 2 s, the net power
to the ICRH antenna, PICRH=6 MW, exceeds the NBI power
injected into the torus, PNBI~4.5 MW. Power deposition calculations show that inside ρ=0.3 the ICRH power is even
twice the NBI power, however ions are still stronger heated
than electrons. The lower traces in figure 3 illustrate the suppression of the central W concentration by central wave
heating as discussed above. In summary, the improved
H-mode developed on ASDEX Upgrade combines improved
confinement (H98(y,2)>1) with high stability (βN>2.5) in long
stationary discharges for a rather extended range of parameters. Future work on improved H-modes is planned along the
Figure 2: Performance vs. (a/R)0.5·βp. Data base: all improved H-mode
studies in 2003/2004, plus some earlier high density discharges, including
low power phases. (a/R)0.5·βp=1 roughly corresponds to 40 % bootstrap
current fraction.
Figure 3: Example of an improved H-mode with strong ICRH. Stationary βp
by feed back control of NBI power, feed forward control of ICRH power.
During stationary phase: H98(y,2)=1.2 and βN=2.6 at q95=3.6. Bottom:
W concentration at different radii, indicating low central concentration during ICRH phase.
following two routes: a further exploitation of the operational range of this scenario on the one hand, and an
improved physics understanding of key issues on the other
hand. The latter area comprises a better account of the confinement improvement, the mechanisms responsible for
keeping the q-profile stationary, the reasons for the benign
MHD behaviour during the high performances phases, and
experiments with stronger central wave heating by applying
both ICRH and ECRH together.
7
ASDEX Upgrade
4 Tungsten Programme
data calculated by Plane-Wave Born approximation (PWB,
Cowan). For the plasma temperatures below 1.7 keV the
VUV spectrum is dominated by the well-known quasi-continuum at 5 nm, emitted mainly by ionisation states between
W27+-W35+. Whereas this part of the quasi-continuum could
be simulated satisfactorily, the emissions with wavelengths
above 5.4 nm could not be reproduced. For the hot background plasma (Te0>2 keV), spectral lines from W39+-W45+
overlay the quasi-continuum emission. These lines were well
described by the model. In the soft X-ray region 90 % of the
detectable emission of tungsten below 2 nm is observed
between 0.4 nm and 0.8 nm. Comparison to modelled spectra from ADAS shows small deviations in wavelength. As
expected, there are differences in the intensity envelope
between the measured and modelled spectrum but the basic
structure of the emission is well reproduced. Only the strong
E2 spectral line at 0.793 nm originating from Ni-like W is
strongly underestimated, suggesting that inner shell ionisation of W45+ (3d10 4s1) plays a significant role in the level
population, a process not yet considered in ADAS. The modelling of the spectral features in the soft X-ray leads to the
same W concentration as derived from the total radiation,
interpreted with a cooling factor based on ADAS data.
The next step device – ITER, will start with a material mix
of Be in the main chamber, W at the divertor baffles and C at
the strikepoints. This choice is motivated by the different
demands set by the plasma wall interaction at the different
positions. However, the still unsolved problem of T co-deposition may lead to the need of exchanging the CFC components before injecting T into ITER. Additionally, probably
at a later phase of the ITER operation, all PFCs have to be
transformed into high-Z components in order to provide
operational data for a reactor. ASDEX Upgrade has implemented a W programme in order to prepare for the decisions, which have to be made for ITER and beyond. It has
progressively increased the use of W PFCs in the main
chamber since 1999.
4.3 W Limiter Erosion
The W erosion at the guard limiter, the central column and
the upper divertor is monitored by spectroscopic tungsten
influx measurements (WI, 400.8 nm) by more than thirty
dedicated lines of sight. The influx densities (ΓW) show a
wide variation from below the detection limit (2⋅1017 m-2s-1)
in ohmically and ECR heated discharges to values of ΓW
≈1019 m-2s-1 in plasmas with ICRH or NBI heating. ΓW
depends strongly on the distance between limiter and separatrix, with a decay length of about λ=1.5 cm. Measuring
simultaneously the deuterium influx, the effective erosion
yield Yeff=ΓW /ΓD , which includes the sputtering by deuterium as well as by plasma impurities can be extracted. It
ranges from below 10-5 to about 2⋅10-3, and approaches 10-2
for transient phases. From thermocouple measurements and
ΓD the average deposited energy per deuterium ion can be
calculated for discharges with long steady state phases. It
turns out that the measured Yeff can only be explained by the
contribution of a considerable amount (%-range) of fast particles from auxiliary heating which are responsible for up to
90 % of the sputtered W. The net W erosion was measured
post-mortem by X-ray fluorescence analysis. Depending on
the position on the tiles an erosion of up to 1.5 µm was
detected.
Figure 4: View into the upper divertor of ASDEX Upgrade. The graphite
tiles were coated by 4 µm of W deposited by PVD.
4.1 Technical implementation of the W-programme
Before the 2003/2004 campaign the upper divertor, the
outer baffle at the lower divertor as well as one of the guard
limiters at the low field side had been equipped with W
coated tiles. The W surfaces now comprise about 24.8 m2,
representing 65 % of all plasma facing components. Since
larger erosion was expected in the divertor region, W coatings with 4 µm thickness were used, deposited by plasma
arc deposition at Plansee. Melting of the W layer was found
at the tile edges in the strike point region of the upper divertor, since no tilting of the strikepoint tiles was applied in
order to allow for an independent choice of the directions of
Ip and Bt.
4.4 Operation with W Divertor
Discharges with low power NBI heating showed increased
W concentrations (cW), but in most scenarios there was no
obvious difference to discharges run in the lower (C based)
4.2 Refinement of central W diagnostic
A new ADAS extension sets up an infrastructure for all ionisation states with intermediate quality data, using collisional
8
ASDEX Upgrade
divertor (LSN). Even during a continuous transition from
USN to LSN no significant change in the W content could
be identified. Discharges at high density and high heating
power were performed. A βN=2.85 at an H-factor H98,y2=0.95
is reached, combined with a low W concentration (cW ≤2⋅10-6),
which was constant throughout the divertor phase. During
these discharges, power loads of up to 15 MWm-2 are
reached in the upper divertor and during ELMs even values
between 20-30 MWm-2 are observed. In hydrogen discharges cW was almost always below the detection limit of
about 2⋅10-7. The reason may be found in the reduced source
due to the lower sputtering rate, caused by a lower C contamination usually observed in hydrogen discharges.
Additionally, the lower confinement and the higher ELM
frequency may also contribute to the strongly reduced W
concentrations.
Figure 5: Core tungsten concentration from VUV spectroscopy for Ar seeded and non-seeded discharges with different ELM frequency (Solid lines
connect data form the same discharge).
5 Impurity transport and Control
4.5 Compatibility with plasma scenarios
The long-term evolution of the W concentration was evaluated in identical ohmic discharges, eliminating the strong
influence of the transport observed in additionally heated
plasmas. During 2001/2002 (7.1 m2, W central column),
typical W concentrations of cW=5⋅10-7 were observed at
ne=2.5⋅1019 m-3. With the increasing W coverage cW also
became larger. At present, usually cW=2-3⋅10-6 is observed,
i.e. an increase by a factor of about 5. As expected, this factor is larger than the increase in surface area pointing to the
fact that there are regions with higher source rate/penetration probability than the central column. A long-term
increase of plasma temperatures is observed at the outer
divertor, pointing to a reduction of the edge radiation,
although the central C concentrations did not change significantly. The critical issues when operating with a W wall,
which were already identified in the previous years, were
studied in more detail and the concepts for overcoming these
issues were optimized further:
– Contact with W surfaces in limiter configuration is
reduced by an early X-point formation.
– Transport in the plasma centre is increased above the neoclassical value by the addition of central RF heating at the
20-30 % level.
– Phases with low ELM frequency were avoided by pellet
ELM pacemaking or by higher heating power. An integrated exhaust control scenario featuring pellet ELM pacemaking and seed Ar radiative cooling has been developed
to cope with the conditions of a carbon free device with a
very low intrinsic radiation level. ELM pacemaking
appears to be a tool not only for the control of the type-I
ELM target power load, but also for the core tungsten content (figure 5).
The development of integrated discharge scenarios has to
include the control of impurity concentrations. For the
H-mode and improved H-mode scenario, impurity transport
in two radial regions was identified to be of relevance: the
H-mode barrier and the central part of the plasma inside of
the confinement region, i.e. inside of r≈a/3.
Transport in the H-mode edge barrier is dominated by convective impurity transport with strong inward drift velocities. Quiet H* phases of extended duration lead to a loss of
impurity control, and have to be avoided by enforcing a sufficiently high frequency of type-I ELMs. This is accomplished by either applying heating powers well above the
H-mode power threshold or by active ELM triggering with
pellets.
In the centre, a peaked density profile is accompanied by
density peaking of the impurities, which becomes very
strong for high-Z elements like tungsten. This central peaking vanishes when adding a sufficient amount of central
wave heating. This technique is now a well-established experimental control tool and proved to be especially important
in discharge scenarios without sawteeth, i.e. improved
H-modes. The present understanding attributes the flattening
effect to an increase of the turbulent transport. The temperature profiles in discharges without an internal transport barrier are generally observed to be self-similar: an increase of
central heat deposition thus leads to an increase of the central
heat diffusion coefficient c and anomalous diffusion coefficient for main ion and impurities. This increase of anomalous
diffusion counteracts the neoclassical inward pinch effects,
like the Ware pinch for the main ions, and the impurity
inward pinch caused by the main ion density peaking.
9
ASDEX Upgrade
The central diffusion coefficient was a factor of 10 above
Dneo for central ECCD and approximately equal to Dneo with
pure NBI heating. In a discharge, which only had central
ICRH with similar maximum power density as in the ECRH
cases, a central diffusion coefficient of D≈2Dneo was measured, while off-axis ICRH yielded D≈Dneo. In all plasmas
with dominant anomalous transport, the measured inward
pinch parameter v/D was low.
The effect of central ICRH on Ne transport was studied in
improved H-mode. Densities of fully ionised Ne were
obtained from charge exchange recombination spectroscopy
(CXRS). For a Ne puff of 20ms duration, the measured density evolution on the channels with r/a below ≈0.5 were fitted to obtain transport coefficients. Two deuterium discharges at Ip=1MA, PNBI≈6.7 MW with different coupled
ICRH powers were studied: 3.6 MW in #19089 and 2.5 MW
in #19090. In the discharge with lower PICRH, the central diffusion coefficient is about a factor of 2 lower, and the drift
parameter v/D (v is inward) increases by about a factor of 2.
Dneo is very similar in both discharges within a factor of 2 of
the measured central values. However, there is a stronger
neoclassical inward pinch parameter vneo/Dneo in #19090
being a consequence of the increased peaking of the density
profile.
5.1 Impurity Transport Experiments
For Si and Ne, the change of the transport coefficients with
the addition of on- and off-axis wave heating was studied. In
type-I ELMy H-mode discharges, direct measurements of
the transport coefficients of silicon were performed using
laser blow-off. The Si density evolution was inferred from
the change of the soft X-ray radiation and subsequently fitted by numerically calculated solutions of the radial transport equation. The transport induced by sawtooth crashes is
treated by assuming a complete flattening of the impurity
density inside the mixing radius. Thus, the evaluated impurity diffusion coefficient represents the transport between the
sawtooth crashes.
Figure 6: Measured and neoclassical diffusion coefficient of Si, measured
effective and neoclassical ion heat diffusivity, for a series of H-mode discharges with NBI heating PNBI=5 MW and additional ECR heating
PECRH=0.8 MW at different radial positions. The various power deposition
profiles are shown in the right graph.
Figure 6 shows the results for a series of type-I ELMy Hmode discharges with 5 MW of NBI without/with 0.8 MW
of ECRH at different plasma radii. The discharges with NBI
only and ECRH at r=0.43 m show a similar radial dependence of D and χeff. Inside of r≈0.15 m, the Si diffusion coefficient equals the neoclassical value and χeff is below χi,neo.
For r>0.15 m, D increases with radius and at r=0.4 m, it is
about an order of magnitude above Dneo. There is a drastic
change of the transport parameters for the cases with central
ECR heating. χeff rises by up to a factor of 10 for radii
greater or equal to the deposition zone, while the local
change of χeff is small at the edge due to the minor change of
Pheat. In the core, also the Si diffusion coefficient increases
with central ECRH by a factor of 3 to 4.5 to values around
D=0.3 m2/s, which is a factor ≥3 above the neoclassical
level. Around r=0.4 m, there is only a minor change between
the different heating scenarios.
In a series of H-mode discharges, where sawteeth were suppressed by 0.8 MW of ECCD, similar results were obtained.
Figure 7: Ratio of central and edge tungsten concentration versus density
peaking for improved H-mode discharges
5.2 Impurity Control in Improved H-mode
The use of central wave heating as a control tool to flatten
the main ion density profile and to avoid tungsten accumulation has previously been shown for dedicated improved
H-mode discharges. In figure 7, the sensitivity of tungsten
accumulation on the density peaking is shown for a broader
data base of improved H-mode discharges, containing purely NBI heated plasmas (circles) as well as discharges with
additional ECR- (diamonds) and ICR-heating (squares).
Filled squares are used for plasmas with PICRH≥3 MW and
filled diamonds for cases with PECRH≥1 MW. The tungsten
concentrations are derived from two spectroscopic measurements. The intensity of the W quasi-continuum at 5 nm,
10
ASDEX Upgrade
which is emitted from ions around W28+, delivers an edge
concentration cW1 keV for the plasma radius with Te of about
1 keV, and the intensity on a W46+ line at 0.793 nm is used to
deduce the central concentration cW3 keV at Te≈3 keV. The
ratio of the tungsten concentrations cW3 keV/cW1 keV covers a
wide range from about 1 to almost 100, with a strong
dependence on the density peaking ne(ρpol=0)/ne(ρpol=0.8).
Highest density peaking and strong tungsten accumulation
is found for discharges with pure NBI heating or with a low
amount of wave heating, while discharges with sufficient
wave heating have flat density and flat tungsten concentration profiles. The tungsten accumulation occurs inside of
ρpol=0.4, as was deduced from the peaking of total radiation
profile.
Carbon concentration profiles have been measured in
improved H-modes with CXRS. Here, the effects are of
course less dramatic compared to tungsten but show a similar trend with density peaking. Central values of cC=3 % are
reached in cases with peaked density profiles which are
reduced to the 1 % level for flat density profiles with sufficient central heating. For the pair #19089/#19090, the strong
Z-dependence of the impurity accumulation shall be further
illustrated. In #19090, the density profile is peaked with
ne(0)=2ne(r=a/2), while it is only ne(0)=1.3 ne(r=a/2) for
#19089. Taking the measured v/D-profiles from Ne, one can
derive the peaking of the steady state Ne concentration profile, which yields cNe(0)/cNe(r=a/2)≈1.7 for #19089 and
cNe(0)/cNe(r=a/2)≈3.5 for #19090. For W, however, the concentration ratios are cW3 keV/cW1 keV≈6 for #19089 and
cW3 keV/cW1 keV≈60 for #19090.
Figure 8: Er shear profiles and radial correlation length measurements in
L-mode and H-mode discharges.
L-modes is between 0 and -75 V/cm2 and in H-modes
between -150 and -250 V/cm2.
This year for the first time radial correlation lengths were also
measured by stepping the frequency of the second reflectometer away from the first and cross correlating the corresponding fluctuation signals. The radial correlation length is the
separation at which the coherence between the two signals
drops to 1/e. Lr results are also shown in figure 8 for an
L-mode and H-mode discharge at the plasma edge (normalized radius ρpol∼0.98). An Lr of 0.09 cm is obtained in
H-mode and 0.24 cm in L-mode. This confirms that enhanced
edge shear is correlated to a reduction in Lr, consistent with
the hypothesis that sheared flow distorts turbulent eddies.
6.2 High precision, high resolution Thomson scattering
Transient recorders combined with advanced background
noise treatment (achieved by the use of software) are now
used routinely for the vertical Thomson scattering system
(VTS). Together with an optimized diagnostic hardware this
6 Diagnostic enhancements
6.1 Radial Correlation Doppler Reflectometry
The confinement improvement and reduction of turbulence
observed in H-mode is believed to be linked to the radial
electric field shear. This can be investigated by comparing
turbulence properties (e.g. the radial correlation length, Lr)
with the magnitude of the Er shear (dEr/dr). Using the new
microwave technique of radial correlation Doppler reflectometry, both Er shear and Lr can be measured simultaneously.
Doppler reflectometry differs from standard reflectometry
in that the antennas are tilted so as to measure the back-scattered radiation from a non-zero turbulent wavenumber k⊥.
From the Doppler shift in the received signal, the plasma
rotation (generally dominated by the ErxB velocity) can be
obtained, and hence the Er radial profile. With a second
reflectometer, two simultaneous Er profiles are measured
from which the instantaneous shear is extracted. Figure 8
shows an example of the shear measured in an L-mode and
H-mode discharge. Note how the shear is localized at the
plasma edge and minimal elsewhere. Typically at ASDEX
Upgrade the maximum negative edge Er shear measured in
1.4
0.3
#19047
Z [m]
0.7
Z [m]
1
0
0.0
ICRH
antenna
10
-0.7
-1.4
0.8
separatrix
flux surface
limited by
divertor
1.7
R [m]
2.6
scattering
volumes
-0.3
2.10 2.18
R [m]
Figure 8a: Positions of the scattering volumes of the VTS system for plasma
edge measurements
11
ASDEX Upgrade
improved the signal-to-noise ratio by one order of magnitude for small scattering signals. It is now also possible to
fire the lasers in burst mode with a delay between the lasers
down to 500 ns. The scattering volumes form a 2D matrix in
the poloidal cross section (figure 8a, see above). This allows
fine structures in ne and Te profiles to be measured.
Localized maxima and minima (“blobs” and “holes”) in ne
and Te were measured quantitatively during type-I ELMs
(figure 9). The toroidal mode numbers determined from the
poloidal geometry of the blobs agree with the most unstable
peeling-ballooning modes.
L-mode plasmas can reliably be diagnosed with a time resolution depending on the lithium beam intensity, in the best
cases down to 100 ms. Time resolution is not sufficient to
resolve ELM events which take place on a sub-ms timescale.
ELM-affected data must be cut out before evaluating the
inter-ELM temperature in ELMy H-mode plasmas. This is
possible as long as the ELM frequency is lower than half the
frame rate.
Results from electron-heated plasmas indicate significantly
different Ti and Te. Also, due to different gradient lengths, a
crossover of electron and ion temperatures of about 3-5 cm
inside the separatrix is typical. Data from NBI-heated plasmas agree with core CXRS using heating beams where both
diagnostics overlap. In QH-mode, extremely high edge
Ti-gradients of more than 600 eV/cm were found, while low
power ohmic discharges show only 20 eV/cm. Absolute ion
temperatures were successfully measured in a range from
50-2000 eV, showing that the diagnostic system is ready to
provide desirable edge ion temperature information.
Figure 9: ne and Te contours 113 µs after the maximum in Dα− intensity of
an ELM in the poloidal plane of the plasma. A threefold (twofold) blob
structure in ne (Te ) exists outside the separatrix.
6.3 Edge ion temperature measurements
The issue of radial edge Ti-profiles has been addressed by
bringing a new diagnostic into operation. A neutral lithium
beam is injected into the plasma and used for charge
exchange recombination spectroscopy (CXRS) on fully ionized helium and carbon ions. Ti is calculated from spectral
fits to the line radiation of C VI (529.0 nm) and He II
(468.5 nm). Equilibration of the impurities with the main
plasma ions is fast enough that temperatures nearly identical
to the main plasma can be assumed. Systematic line broadening effects (collisional mixing, Zeeman broadening) are
corrected by detailed ADAS calculations. Gating of the
beam is necessary to remove background radiation and
extract the small beam-induced CX-contribution to the spectral line. The detection system, consisting of two CzernyTurner spectrometers with high-speed CCD cameras, operates at up to 250 Hz frame rate. The narrow beam (1 cm) and
closely staggered optical fibres (6 mm) enable unprecedented
spatial resolution in all major plasma regimes (figure 10).
Figure 10: Ion temperature measurements in multiple plasma regimes.
In most standard regimes (Ohmic, L-mode, H-mode, QH-mode) edge ion
temperatures can now be measured with high spatial resolution.
7 Technical Systems
In 2004, the experiment was in operation for 76 days, performing 1205 shots in total. 63 days were dedicated to
physics, with 965 discharges. There were two unscheduled
vessel openings, one in mid March and the other in May,
both were caused by broken tiles. The routine summer opening lasted from early August until mid December.
7.1 Machine Core
In the following the vacuum vessel, its gas feeding and
pumping systems, and the supply systems for cryogens and
electrical power are described.
Vacuum Vessel: During the summer opening redesigns were
12
ASDEX Upgrade
realised for the tiles of the outer divertor target and the protective limiters. In addition, the tungsten coating of the plasma facing components was extended. The redesign of the
outer divertor tiles was required due to cracks arising at cut
outs for support elements. The redesign of the four protective limiters now provides actively cooled heat sinks with a
larger toroidal width, to increase the wetted area of the tiles.
The tungsten coating could not be extended in the full range
as planned in 2003. The roof baffle W-coating had to be
postponed until 2005 due to budget cuts. Only one of the
four protective limiters could be installed with a 0.3 mm
thick W-layer. For the remaining limiters manufacturing
problems have postponed their W-coating until 2005. In the
ICRH antenna 4, part of the side limiters received W-coated
tiles as a further step in W-coating all carbon surfaces pointing towards the plasma.
Gas feeding and Turbo Molecular Pumping (TMP) system: To remove the gas bottles from the experiment hall for
diagnostics, additional heating systems and the plasma gas
feeding system, an outdoor cubical was commissioned and
the required connection pipe work to the experiment core
installed. The matrix system for 20 fast gas-feeding valves
was ordered. It will be commissioned in 2005. The operational safety of the TMP system has been further increased.
In case of a transient supply failure for electricity, cooling
water or pressurized air, the TMPs are ramped-down. After
5 minutes, it will be checked to see if all systems are available again. Provided that the torus vacuum remained stable
during this period an automatic restart will then be initiated.
To increase the lifetime of the TMPs the revolution speed
(min-1) is reduced from 33.000 to 26.000 for long standby
periods like weekends.
Cryogenic supply system: The extensions planned in 2003
for supplying the cryo pumps of the NBI test stand and the
ASDEX Upgrade plasma vessel with the TC 50 liquefier
were commissioned in 2004. The direct recirculation of
clean helium (He) flash gas to the suction side of the TC 50
compressor is now in operation. In addition, the liquid nitrogen shielded valve box was commissioned, which is required for the helium distribution between the ASDEX
Upgrade and the NBI cryo pumps.
Power supply: The activities for extending the system and
improving its availability were carried on. The call for tender for the new EZ5 generator was released. It is envisaged
to install stepwise five flywheel units with 8 MVA/36 MJ
each. Steps were taken to provide separate equipment for
damping the shaft oscillations of the generators EZ3 und
EZ4 to become independent from equipment required for
ASDEX Upgrade operation. Two air-cooled inductors (5 kA
dc and 5 kA 25 Hz for 15 s) were commissioned and two aircooled damping thyristors with the same rating will be procured in 2005.
7.2 Data Acquisition and Computer Infrastructure
The move from classical post-mortem CAMAC to real-time
PCI/compactPCI-bus based data acquisition (DAQ) is going
to speed-up. The Thomson-Scattering diagnostic has got an
additional cluster of four powerful SunFire V240 computers
providing extended real-time capabilities. A similar upgrade
was applied to the Mirnov-Probes diagnostic, acquiring four
times 600 Mbytes of data on a cluster of four SunFire V240
computers. Other diagnostics like the MSE, the ECE, and
the magnetic measurements already use or are about to use
PCI- or cPCI- hardware as well. To support this tendency,
cPCI-bus version of the TDC as well as a cPCI-card for digital I/O was derived from the primary TDC design. Both
developments will share the same Solaris device driver and
are extending the Solaris real-time DAQ facilities to comprise systems featuring the cPCI-bus. The new cPCI-DIO in
particular, directly interfaces to the AUG magnetic field
integrators. The prototype of this card is currently being
tested and we hope to launch the real-time enabled magnetic
field diagnostic in late summer 2005.
Besides these DAQ developments, basic infrastructure
enhancements were made to support the increasing load on
the local data processing facilities. The AUG server systems
have been upgraded by an additional SunFire 4900. Additional disk space has been acquired and first steps to integrate the new and existing fibre channel disk arrays into a
redundant SAN configuration have been taken.
Meetings with remote participants (Helsinki, Cork, Padua,
Budapest, Lisbon, Lausanne, etc.) were conducted on a regular basis using the H.323 video conferencing (VC) facilities of the ASDEX Upgrade seminar room. With the experience of two years of running VC meetings, these facilities
were brought to a further level of sophistication in 2004: The
remote participants video image was moved from behind the
local speaker to the side. An additional sound channel for
the remote voice was added at the same place. These
changes give remote users a more adequate position in discussions and enhance voice comprehensibility by improving
the psychoacoustics situation. Remote control of blinds and
room light is now included in the media control.
7.2.1 New Real-Time Control and Data Acquisition System (r-t CODAC)
A new integrated r-t CODAC was designed at ASDEX
Upgrade. Multivariable control, and r-t reference computation at millisecond cycle times are central features.
Algorithms can be easily added and tested with data from
previous discharges (replay) or from system models. Selfmonitoring and alarm propagation make the system suited
for safety critical missions.
The new CODAC is an open distributed system where plasma controllers and diagnostics exchange r-t signals via a
shared memory network, and access a global nanosecond
experiment time with dedicated boards. CODAC software
13
ASDEX Upgrade
consists of an infrastructure layer for distributed process
synchronization, signal exchange, alarm propagation, logging, and protocols, and of an application layer with specific
control and data acquisition tasks freely allocated to controllers. Operation is cyclic and data driven.
The Cycle Master process drives the common base cycle
(slow for pulse preparation, fast for plasma control), performs watchdog surveillance and collects alarms from applications. Where required it triggers protective actions.
I/O processes transform about 400 sensor signals into SI
units, and output command signals to actuators. Evaluation
processes refine input signals for use by feedback and monitoring processes. The Reference Value Injector translates the
experiment leader’s discharge programme trajectories (controller modes, feed forward and feedback target values, etc.)
into r-t reference signals. If triggered by the Discharge
Monitor, (see below) it switches to an alternate segment of
the discharge programme. It is also capable of rule-based
computation of reference values (e.g. for soft landing or
instability handling) from the current plasma and machine
state – a feature that can be extended to a top-level reference
value feedback loop for future intelligent plasma control.
Two multi-variable feedback processes have been implemented: Magnetic Feedback controls plasma current, plasma vertical and radial position (fast), and plasma shape
(slow). Performance Feedback controls plasma kinetics via
fuelling and heating actuators. A Performance Actuator
Control process handles actuator priorities, clippings, and
performs failure compensation. Feedback and monitor processes check physical and technical quantities against operation and machine limits. The Discharge Monitor evaluates a
list of physical or technical conditions. It can instruct the
Reference Value Injector to branch to a new segment to optimize the plasma or handle exceptions. CODAC has been
tested with replay and live runs at cycle times down to
1.85 ms (formerly 3 ms). Final commissioning, which involves extending feedback configurations, exploiting rulebased reference value computation, and integration with
experiment automation tools is scheduled for 2005.
20 MW have been requested with maximum pulse lengths of
individual beams exceeding 8 s. The power level of each
source can be varied quasi-continuously by on/off-modulating the extraction voltage. This is implemented into a feedback loop for controlling the NBI power with respect to a
requested β waveform. Feedback control of the NBI power
was frequently applied during improved H-mode studies.
The possibility to vary the vertical alignment of the two offaxis, tangential beams within a certain range has been extensively used during the current drive studies in order to optimise the off-axis beam deposition.
Maintenance work during the shutdown period of ASDEX Upgrade had to be restricted to a necessary minimum due to manpower reasons. One RF source had to be replaced after an internal leak was detected and a faulty arc power supply was repaired.
7.4 Ion Cyclotron Heating
In 2004, the ICRF system continued to provide reliable
power for the experimental programme, which led to requests
for long pulses and power in the 5 to 6 MW range. With
30 MJ, a record level of energy to the antennas was achieved.
No further delivery of a refurbished tube (which would be
the fourth one) occurred in 2004. This has not affected operation. Delivery can be expected in 2005. Further solutions are
being developed to re-establish the nominal power of the
generators, which has declined over the years. This is only
partially mitigated by the refurbishment of the tubes. The
AFT ferrite tuners, meant to provide for one double system
automatic matching to the load variations during a discharge,
were not delivered. A solution to reduce the loss in the system, which is presently too high, is still outstanding. During
the summer break, some substantial changes were made to
the ICRF system: the control was upgraded from Simatic S5
to S7, and the data acquisition was extended to increase the
number of fast data acquisition channels for experiments
requiring high sampling rates. To accommodate these improvements, and allow operation with reduced manpower, the
control room was reorganised and brought up to standard.The ICRF power was available from the beginning of
the campaign.The manufacturing of new antenna straps for
antennas 3 and 4, approved in July 2004 for installation in
2005, has started. The new straps have reduced electric fields
(as those installed in summer 2002 in antennas 1 and 2) and
some additional features: by proper arrangement of holes in
the straps, pumping inside of the antenna is improved and the
electrical characteristics of the two straps within an antenna
are equalised. A substantial effort was also made to support
the ICRH system for W7-X with work on the ICRF test stand
and manufacturing follow up.
7.3 Neutral Beam Heating
Neutral beam injection (NBI) is used as the main source of
heating power. The NBI system provides reliable total power
of up to 20 MW (D0) from two injectors with four beams
each. Two of them act additionally as “diagnostic beams” for
the MSE and CXRS measurements. As in former years, the
availability of the NBI system has proven to be rather high;
only two days of operation were lost for one injector that
developed a water leak in a calorimeter bellow. This fault
could be repaired during a short break of the ASDEX
Upgrade operation.
The tokamak experiments draw benefit from the various
capabilities of the NBI system. Heating powers up to
7.5 Electron Cyclotron Heating
The existing ECRH system with 140 GHz/2 MW/2 s was
regularly used in the experiments. However, the gyrotron
14
ASDEX Upgrade
Zodiak-2 got a vacuum leak and cannot be used anymore.
Thus only an installed power of 1.5 MW is now available.
A new ECRH system with 105-140 GHz/4x1 MW/10 s is
under construction. After a considerable delay, the factory
test of the first two-frequency gyrotron (design IAP Nizhny
Novgorod, construction GYCOM Nizhny Novgorod) was
done in Nov. 2004. The planned parameters were not yet
achieved in long pulses. The gyrotron delivered only
720 kW at 140 GHz and 700 kW at 105 GHz, both in 10 s
pulses. Reportedly, further conditioning resulted in 900 kW
at 140 GHz for 7 s pulses. The design is a compromise and
is neither optimised for 140 GHz nor for 105 GHz. This
gyrotron will be delivered to IPP in Jan. 2005. Installation
and commissioning on site together with the new infrastructure will require several months.
The second gyrotron is essentially of the same type, but
capable of working at additional frequencies within this
band. It is already constructed and produced 1 MW at
140 GHz, 850 kW at 124 GHz and 750 kW at 105 GHz, all
in 0.1 s pulses with a boron nitride window. A tunable double disk output window will replace this window, which is
still in design. The infrastructure for this second gyrotron is
under construction. The transmission system, designed at
IPF Stuttgart, is nearly finished. The tunable double disk
torus window is in construction at FZK Karlsruhe.
Figure 11: Ratio of heat pulse diffusivity to power balance diffusivity versus
the so-called effective collisionality relevant for TEM stabilization. The
points below unity are clearly outside of the experimental uncertainties.
deduced from the propagation of heat pulses is observed to
be fast at low collisionality, to decrease gradually with
increasing collisionality and to eventually drop below the
power balance diffusivity. The results are shown in figure 11. Based on gyro-kinetic calculations this behaviour
can be attributed to the stabilization of the TEM turbulence
by collisionality. Furthermore, the calculations indicate that
the drop of the heat pulse diffusivity below the power balance value is explained by the fact the electron heat flux is
driven by the Ion Temperature Gradient driven turbulence
when the TEM modes are stable. Indeed, the calculations
show that, in this case, the electron heat flux driven by the
ITG is sufficient and has the required dependence upon
R/LTeTe to explain the very low heat pulse diffusivity.
R/L
8 Core Plasma Physics
8.1 Electron heat transport
Electron heat transport is believed to be governed by microturbulence. In plasmas with dominant electron heating provided by ECH and exhibiting Te>Ti, comparisons with turbulence stability calculations strongly suggest that the
instability is the Trapped Electron Mode (see Theory section). Two main properties of this instability are the existence of a threshold in R/LTeTe and stabilization by increasing
collisionality. Experimental indications of a threshold have
been observed in the last years (see previous Annual
Reports), but its actual existence could not be evidenced.
The threshold is expected to be revealed by a jump-like
behaviour of the propagation speed of heat pulses generated
by ECH power modulation. New experiments have been carried out in which the electron temperature gradient have
been varied over the adequate range using two ECH beams.
The analysis of the heat pulse propagation shows a sudden
increase of the heat pulse diffusivity, which can be attributed
without ambiguity to the existence of a threshold. This is
confirmed quantitatively by transport simulations. Other
experiments using impurity induced cold pulses confirmed
the generality of the behaviour of electron heat transport
observed with ECH heat pulses.
The stabilization of TEMs by collisions have been investigated in discharges with a density ramp. The heat diffusivity
8.2 Angular momentum transport
The radial angular momentum diffusivity χφ has been calculated with the ASTRA transport code using rotation measurements from charge exchange recombination spectroscopy in various H-mode discharges. Comparison with
the thermal conductivities χi, χe yields information about the
nature of anomalous transport and a possible stiffness of
toroidal rotation profiles. The combined use of ICR and NBI
heating allowed the roles of momentum source and heat flux
to become disentangled, showing the dominant effect of
ICRH on rotation to be the enhancement of radial transport
with power flux. The transport analysis reveals that generally the momentum diffusivity χφ is similar to the thermal conductivity. To analyse a possible stiffness of rotation profiles,
its gradient lengths have been compared to those of the ion
temperature. The results are summarised in figure 12, where
R/L Vφφ are
the normalised inverse gradient lengths R/LTiTi and R/LV
compared for various discharge scenarios. For standard H15
ASDEX Upgrade
Figure 12a: Delay between the introduction of the supersonic D gas jet and
the onset of the next ELM. The ELM release is due to particle fuelling, no
prompt trigger is observed. To achieve a reasonable response time (<1 ms)
massive gas fluxes are required, causing severe confinement degradation.
Consequently, ELM pacing by gas jet is not suitable at ASDEX Upgrade.
R/LLV
R/LLTTii versus R/
Figure 12: R/
Vφ φ for various scenarios
mode conditions, the ion temperature exhibits the usual stiff
behaviour with R/LTi
Ti around 5. This is not observed in the
R/L Vφφ are
rotation profiles, where much smaller values of R/LV
also observed. Such very flat central rotation profiles with
R/L
R/LV
Vφ φ close to 0 are observed in high density H-modes.
Steeper gradients with R/L>10 exist for both rotation and
ion temperatures in the barrier region of ITB plasmas, suggesting a similar mechanism of transport reduction for both
transport channels.
Another possibility to envisage ELM pacing aims at modifying the edge current profile. This is the basis for the magnetic triggering approach first demonstrated at TCV. Via inductive effects, it is understood that changing the vertical
position of up-down asymmetric plasma drives edge current.
Using the technique of vertical plasma position oscillations,
magnetic triggering of type-I ELMs was achieved at
ASDEX Upgrade for the first time. Modest vertical motion
(only about twice the value caused by an intrinsic ELM anyhow) is sufficient to drive ELMs with the driving frequency
fD. In the whole technical accessible frequency range
fD/f0=0.75-1.8 locking was estabilshed. Interestingly, both
increasing and decreasing ELM frequencies can be
obtained. A relation for the plasma energy content W~f -0.22
was observed. This is a value very similar to that found in
pellet ELM pacing experiments. Like the pellet approach,
the triggered ELMs showed no sigificant difference with
respect to intrinsic ELMs. Also, the inverse correlation
between ELM frequency and size found empirically for the
intrinsic ELMs is kept in the case of magnetic triggering.
Thus, this method is suitable for ELM mitigation as well.
Further efforts are planned to investigate possible ELM pacing techniques like micro pellet injection using laser blow
off. Besides this, activities will concentrate on detailed
investigations of the ELM dynamics.
8.3 ELM pacing
ELM pacing has been demonstrated as an option to combine
high confinement and tolerable ELM sizes in the type-I
ELMy H-mode. This approach, first concentrated on pellet
injection, has now been broadened and alternative trigger
tools have been investigated. Our efforts were concentrated
on supersonic pulsed injection (SPI) of D gas jets and the
“magnetic triggering” using vertical oscillations of the plasma column.
SPI does result in earlier ELMs, usually after a delay of a
few milliseconds. The distribution of this delay is plotted as
a function of the total number of injected D atoms in figure 12a. Data scatter is due to the random phase in the ELM
cycle at which the gas is introduced. The observed ELM
period decrease is due to particle fuelling. In contrast to pellet injection, no prompt ELM trigger takes place. A particle
content of about 1020 D atoms is required to trigger a sufficiently fast ELM. This requirement would cause e.g. a particle flux of 5x1021 D atoms s-1 for ELM pacing to 50 Hz
(injection technically limited to 2 Hz). For this configuration
such gas fuelling would raise the initial ELM frequency f0 to
about 100 Hz and degrade confinement. This indicated that
the available SPI system is not suitable for ELM pacing at
ASDEX Ugrade.
8.4 Studies of the QH-mode regime
The Quiescent H-mode (“QH-mode”) regime, discovered in
DIII-D and reproduced in ASDEX Upgrade, is attractive
because of the absence of ELMs, combined with good stationary H-mode confinement and low pedestal collisionality. QH-mode is achieved with counter neutral beam injection and high plasma-wall clearance. ELMs are replaced by
benign, continuous edge MHD activity, most prominently
16
ASDEX Upgrade
the “Edge Harmonic Oscillation” (EHO), which owes its
name to the observation of many spectral harmonics due to a
non-sinusoidal perturbation. Figure 12b shows the measured
signal of a radial magnetic field pick-up coil, dBr/dt (top
panel), integrated once for Br (middle), and integrated twice
for a signal that is proportional to the flux surface dispacement (bottom).
angles the current drive efficiency and hence the driven current I decreases and the deposition width d decreases. This
leads to the figure of merrit I/d, the radial current density,
which increases for smaller d.
Previous experiments were all performed with launching
angles resulting in d≈4-5 cm. The (3/2)-NTM could be stabilised at a maximal βN≈2.6 with PNBI=10 MW and
PECCD=1.0 MW. For the (2/1)-NTM a maximal βN≈1.9 with
PNBI=6.25 MW and PECCD=1.9 MW could be achieved. With
an optimized launching angle and a stronger peaked ECCD
profile (higher I/d) an improved stabilisation has been predicted and experimentally observed. For the (3/2)-NTM,
βN=2.6 at PNBI=12.5 MW and PECCD=1.0 MW could be
obtained. For the achievable βN for a given PECCD this gives
the ratio βN/PECCD[3/2]= 2.6 MW-1 at increased NBI power.
For the (2/1)-NTM βN could be raised to βN=2.3 with
PNBI=10 MW and reduced ECCD power of PECCD=1.4 MW
giving βN/PECCD[2/1]=1.64 MW-1 compared to the original
value βN/PECCD[2/1]=1.0 MW-1.
With the newly installed tunable gyrotrons and movable mirrors together with the available realtime capabilities in 2005
these experiences will be applied to arbitrary scenarios in an
automic way.
a.u.
0
•
Br
raw
with comb filter
a.u.
0
Br
#17692
a.u.
0
∫ Br dt ∝ ξ
3.7382
3.7386
time [s]
3.7390
3.7394
.
Figure 12b: Magnetic perturbations during EHO
The toroidal rotation of the EHO allows its time behaviour to
be interpreted as a near triangular kink-like spatial structure.
Gas puffing probably triggers ELMs, therefore pellet
fuelling of QH-mode plasmas is being explored. A slight
density increase to 3.8x1019 m-3 is obtained. Pellets can also
cause the disappearance of the EHO and re-appearance of
ELMs, with a higher plasma density due to changed edge
transport. Hence the stationarity of QH-mode and particle
transport across the H-mode barrier is linked to the occurrence of the EHO.
With counter-injection, there is a large fast particle population in the H-mode barrier region. NBI particles are ionised
inside the plasma and follow outward-pointing orbits into
the steep gradient region, which also shows a strong radial
electrical field. Modelling of the slowing-down distribution
with the ASCOT Monte-Carlo code demonstrates that the
radial electrical field is sufficiently large to reverse the precession drift direction of the fastest ions and to create a resonance with the EHO. This hints at a role of fast particles for
driving the EHO.
8.6 Toroidal Alfvén Eigenmodes (TAE)
The effect of Electron Cyclotron Current Drive (ECCD) on
the TAE amplitude was studied by applying different levels
of ECCD in similar plasma configurations, with equivalent
ICRH power. A constant level of 5 MW ICRH power was
applied and 1.5 MW of ECCD was added for a short time.
Without ECCD, two TAE modes are observed with frequencies around 300-350 kHz and the TAE are frequently
interrupted by sawteeth. By applying 1.5 MW of ECCD
the amplitude of the TAE increases and the TAE survive
most of the sawtooth period. A third mode can also be seen
during the ECCD phase. Therefore, ECCD has a slight
destabilizing effect on the TAE. This could be caused by a
different TAE damping, due to changes in the q-profile,
but more detailed modelling is required to verify this
assumption.
8.7 ITB collapse and ELMs
An Internal Transport Barrier (ITB) is a region in the core
plasma with an unusually steep temperature (or density) gradient. High bootstrap current fraction and enhanced energy
confinement make ITBs an attractive scenario for a steadystate tokamak reactor. However, steady-state ITBs in reactor-like conditions have still to be demonstrated. On ASDEX
Upgrade well reproducible ion temperature (Ti) ITBs are
generated with 10 MW pure Neutral Beam Injection (NBI)
heating, yielding central Ti values up to 25-30 keV. The
drawback is their duration of only several energy confinement times.
8.5 NTMs
The NTM stabilisation with local current drive replacing the
missing bootstrap current by Electron Cyclotron Current
Drive (ECCD) has been successfully continued. The suppression efficiency as a function of the ratio between the
marginal island size Wmarg and the ECCD deposition width d
has been investigated both numerically and experimentally
by a variation of the toroidal ECCD launching angle (see
section University of Stuttgart). For smaller launching
17
ASDEX Upgrade
Power (Hz -1)
Type I-ELMs have been observed to terminate ITBs at JET.
While they canot be avoided in the present experiments, not
even at low plasma current nor using radiation by impurities,
the ELM-free phase is long enough to study the ITB evolution. Newly available fast Charge Exchange Recombination
(CXRS) core measurements show that usually the ITB loss
occurs clearly before the first ELM (figure 12c).
Ti [keV]
1.2e-4
12kHz
12.5kHz
8e-5
4e-5
0
# 18705
24
11.5kHz
f = 10kHz
20
Frequency (kHz)
0.97
40
60
80
D-α (a.u.)
0.99
Sep.
Radial ρpol
Figure 12d: Er spectral power vs frequency and radial position from
Doppler reflectometry for AUG ohmic shot #18813
12
0
0.80
1.01
0.95
0.90
1.00
Time (s)
1.10
Some discharges also show evidence of a second ZF further
in. In the tokamak core region there is enhanced high frequency Er fluctuations but, so far no clear evidence of
coherent peaks. Measurements are currently in progress to
determine the mode structure.
1.20
Figure 12c: Ti time traces from the fast CXRS system and ELMs timing from
the Dα signal (violet). The first ELM occurs after the ITB collapse.
9 Edge and Divertor Physics
Transport analysis with fluid models as well as stability
analysis with the linear gyrokinetic code GS2 highlight the
fast ions fraction as the key parameter triggering the ITB.
For the ITB sustainment, Ti/Te plays an important role as
well. ωExB completes the ITG mode stabilisation when the
growth rate is reduced by the fast particles.
The proposed mechanism can explain the density threshold
for ITB formation and the ITB duration, which is of the
order of the slowing down time. However, a more careful
assessment of the non-thermal ion population is necessary
in order to reach definitive conclusions.
9.1 Density pedestal width and ELM affected area as determined by reflectometry
The width of the density pedestal, ∆ne, as determined by
reflectometry in H-mode plasmas just before an ELM does
not vary significantly with plasma parameters as shown in
figure 13 with respect to pedestal density. In contrast, for
ohmic and L-mode phases, the width increases with density
as indicated for comparison. Comparison of L- and H-mode
discharges with similar pedestal density shows that in
L-mode the width is about a factor of three higher. This is in
contradiction to the hypothesis that the width is determined
by neutral penetration (proportional to 1/n) independent of
the confinement regime. Investigation of the effect of ELMs
on the density profiles shows that the radial extent of the
8.8 Zonal flows and GAM oscillations
Zonal flows (ZF) and associated geodesic oscillations
(GAM) are turbulence generated time varying E×B poloidal
plasma flows. They are of major interest for tokamak confinement as they are predicted to moderate drift-wave type
turbulence via shear decorrelation, and so affect transport.
However, experimental detection of ZF and GAMs is challenging since they appear predominantly as radial electric
field Er or potential oscillations. Recently it was demonstrated that long wavelength Er fluctuations can be measured
with high spatial and temporal resolution using Doppler
reflectometry. Initial results revealed a low frequency
(~kHz) coherent mode in Er (but not in density) scaling in
frequency with the acoustic velocity – consistent with GAM
behaviour. κ shape and q scaling dependencies are predicted
and will be investigated in the next campaign. The spectrogram (figure 12d) shows that Er activity is typically localized around the steep density gradient region inside the separatrix, where the turbulence vorticity is largest. Note the
mode frequency varies across the (~cm wide) ZF region.
∆ ne (cm )
∆ ne ∝ 1/ n e,ped
10
5
0
0
2
4
n e,ped ( x 10 19 m -3 )
6
8
Figure 13: Width of density pedestal in L-mode (dots) and H-mode (diamonds) as a function of pedestal density
18
ASDEX Upgrade
ELM perturbation (20-40 % of the plasma minor radius),
decreases slightly with the pedestal density and is correlated
with the ELM particle losses.
9.4 Influence of a reciprocating divertor Langmuir probe on
the ELM signature
The reciprocating Langmuir probe system run by the NCSR
“Demokritos” team was used to investigate the divertor plasma for a large variety of discharge configurations. One of
the many interesting effects observed was the ability of the
probe to influence the ELM characteristics in discharges
near the L-H threshold. This is demonstrated in figure 15,
where the probe position is shown together with the measured floating potential and Dα signal for such a discharge.
The dashed lines represent the position where the probe
crossed the outer separatrix, just below the x-point. The
main influence on the characteristics occurs while the probe
tip crosses the separatrix and also slightly inside the private
flux region. In contrast, when the probe lies at maximum
extension the ELMs return to their original size, despite the
fact that the whole of the probe body now crosses both separatrices. This suggests that the probe tip current causes this
effect, altering the local edge stability despite its small size.
9.2 Heat load outside the divertor
Divertor and first wall ir-measurements reveal that a fraction
of the power crossing the separatrix can penetrate deep into
the SOL resulting in a flat tail of the radial heat flux profile.
The contribution of this SOL heat flux so far is less than
10 % to the overall power balance. A main contribution to
the heat load comes from ELMs, which deposit about 60 %
of the heat load of non divertor components in contrast to a
20 % contribution in the divertor region. The decay length of
the heat flux in the SOL was investigated by different experiments. It was found to be in the order of a few centimetres
in agreement with the far SOL decay length deduced from
divertor heat flux profiles. The heat flux decay length in the
shadow of the outboard limiters was found to be about one
centimetre.
9.3 Radiation distribution and energy balance during type-I
ELMs
Only 50 % of the ELM energy losses are found as target
load in the divertor, and some 10-20 % estimated on plasma
facing components outside the divertor. In order to understand the destinations of the ELM energy it is necessary to
estimate the radiated energy during an ELM. For this purpose, an improved evaluation algorithm for bolometric data
has been developed, which allows the radiated energy on
type-I ELM relevant timescales to be calculated. It is found
that the radiation due to the ELM is mainly located in the
inner divertor (10 % to 40 % of the ELM energy). This normalised ELM radiation decreases slightly with increasing
normalised ELM energy or decreasing electron density (figure 14). It also decreases with higher heating power or higher q95. The overall energy balance is nearly fulfilled during
discharges with medium heating power, while with higher
power, up to 50 % are missing and probably deposited outside the divertor.
Figure 15: Time traces of probe position (top), floating potential (mid), and
divertor Dα emissions (bottom) for shot #18789.
9.5 ELM perturbation measured by ICRF antennas
ELMs are known to dramatically affect the coupling of the
ICRF antennas by perturbing the density profile in front of
them. Fast measurements show that the response of the four
toroidally distributed antennas to ELMs is not simultaneous.
For the majority of ELMs the antennas’ response indicates a
toroidal propagation of ELM perturbation in the direction
counter to the plasma current, i. e. the same as for the electron diamagnetic drift. A dependence of the toroidal propagation velocities on absolute losses of diamagnetic energy of
the plasma Wmhd during ELMs has been found. The smaller
propagation velocities (both maximal and minimal values)
are correlated with the larger losses of the plasma diamagnetic energy. The average velocity of propagation of the
ELM perturbation is 220 km/s, which corresponds to a
toroidal turn time of 60 µs.
Figure 14: Dependence of the normalised ELM radiation on the normalised
ELM energy (left) and the normalised density (right) for discharges with
5 MW heating power and q95≈4.9.
19
ASDEX Upgrade
The resulting methane yield shows a power law dependence
with ion flux density with γ=-0.46 (figure 17).
9.6 Edge transport analysis of OH and H-mode shots with SOLPS
The two-dimensional tokamak B2-SOLPS edge transport
code package has been used to analyse a series of ASDEX
Upgrade shots in various confinement regimes. On the experimental side, edge ion temperature measurements are
now available for fitting in addition to a wealth of other
diagnostics. The low and high-density phases of the standard
Ohmic shot have been analysed. Transport coefficients were
varied until a satisfactory fit of experimental data was obtained. The transport coefficients obtained were compared
to the neoclassical ones and also to those from first principle
turbulence simulations for the same edge profiles. B2 runs
were also performed with drift terms switched on, and the
resultant calculated electric field is compared to the experimentally measured one in figure 16, showing quite good
agreement. In parallel, two similar ELMy H-mode dis-
Figure 17: The erosion yield versus the ion flux density Γ. The yield shows a
power law dependence: yield ∝Γ-0.46.
9.8 13C gas puff experiments
13CH was puffed to study both the local and global migra4
tion of carbon in the machine. The global migration pattern
was studied by SIMS depth profiling of re-deposited 13C on
a poloidal cross-section of divertor tiles retrieved after the
experimental campaign 2003/2004 at the VTT labs, Finland.
In addition, the local re-deposition at the outer divertor target plate was measured by quantitative determination of
deposited 13C with high spatial resolution around a 13CH4
gas puff valve at the outer target plate (figure 18). The redeposition pattern forms a tail downstream of the puffing
location with a constant angle towards the magnetic field
direction and a vertical shift close to the valve due to E×B
forces on the dissociated molecule fractions and ions. This
pattern provides a strict set of boundary conditions, which
will be used for the validation of Monte-Carlo simulations
of the transport of carbohydrate molecules and their dissociation products.
Figure 16: Comparison of measured and computed radial electric field for
the standard AUG Ohmic shot. (Performed with the “Russian” version of
the SOLPS code.)
charges, one hydrogen, the other deuterium have been
analysed with B2-Eirene. Surprisingly, neutrals seemed to
have similar penetration depths in both cases comparable to
the pedestal width, but there was also a pronounced particle
transport reduction in the barrier region. While the former
would be in line with the pedestal width hypothesis of the
DIII-D group, the latter is in clear contradiction to it.
9.7 Chemical erosion yield flux dependence
The investigations of D/XB value and chemical erosion flux
dependence in attached divertor plasmas by means of inloco calibration hydrocarbon puffing were concluded during
the campaign 2003/2004. The results show a decrease of
D/XBCD←CD
CD ← CD 44 with increasing ion flux (decreasing temperature) for fluxes lower than 2⋅1022 m-2s-1. For higher fluxes no
flux dependence is evident, but discharges with lower local
Te and same ion flux density results in lower D/XBCD
← CD 4 .
CD←CD
Figure 18: Deposition pattern of 13C after puffing 13CH4 through hole in the
divertor plate.
20
ASDEX Upgrade
current, while analytic approximations are no longer applicable.
Electron Heat Transport: In both DIII-D and AUG, common ECH experiments have been performed to investigate
the existence of a transport threshold in ∇Te/Te as predicted
by theory, which show that the same transport behaviour is
found in both devices.
Physics and Control of Neoclassical Tearing Modes
(NTMs): Co-ordinated experiments were carried out in
AUG and DIII-D to study regimes under which NTMs can
be excited (see section 8.5).
9.9 First results from fast ion loss diagnostic
A fast ion detector head for the ASDEX Upgrade midplane
edge manipulator has been developed. It measures the energy
and pitch angle distribution of energetic ions lost from the
plasma core via collisional and MHD-induced transport by
means of the light emitted by a scintillator using two different
systems: a CCD camera with a high spatial resolution and a
set of 20 PMTs with high time resolution. First results were
taken in the limiter shadow with different ion sources from
the nearby neutral injector #2 switched on consecutively,
showing the expected pitch angle and energy distribution. No
prompt losses from injector #1 were seen because of the long
toroidal distance to the diagnostic. First MHD induced losses
were identified during the presence of (2,1) neoclassical tearing mode activity, showing a very high perpendicular velocity
component and total energies between 10 and 20 keV.
10.2 EURATOM Associations
CRPP: The magnetic ELM triggering technique developed
at CRPP was tested in AUG (for details see section 8.3).
ELM control with edge ECH and ECCD was also tested.
First experiments showed a dependence of the ELM frequency on the direction of the current driven at the plasma
edge. Modulation of the edge ECH induced a synchronization of the ELM cycle.
DCU – University College Cork: The ongoing collaboration resulted in the following main advances:
(i) Model-independent confidence bands for q profile
reconstruction using the CLISTE equilibrium code taking both MSE signal accuracy and uncertainties in flux
surface geometry into account.
(ii) Simultaneous interpretation of line-integrated (DCN
interferometer) and local density measurements
(Lithium Beam diagnostic) by CLISTE.
(iii) Integration of the extended Function Parameterisation
(FP) algorithm for rapid q profile identification using
MSE data into the standard FP environment for use in
the new discharge control system.
(iv) Use of ASTRA and TRANSP codes to provide more
detail on ITB sustainment analysis of well-diagnosed
ITB discharges.
(v) Scenario development work and preliminary tests have
been used to design a number of promising experiments to
be carried out in 2005 to promote the understanding and
exploitation of TAEs and their use in providing further
constraints on reconstructed current density profiles.
ENEA, IFP-CNR, Milan: Electron heat transport properties have been investigated with transient transport techniques. Electron temperature profiles and their gradients
have been manipulated by localized injection of steady-state
ECRH in AUG. Transients were obtained by means of Laser
Blow Off of Silicon. Results can be found in section 8.1.
ENEA – Consorzio RFX, Padova: The dependence of
impurity transport on plasma heating schemes was studied.
In particular, the influence of different levels of ICRH power
was assessed. Neon was puffed into improved H–mode discharges and the CXRS data was analysed. For further details
see sections 5.1 and 5.2.
10 International and European Co-operations
ASDEX Upgrade (AUG) co-operations are organised under
IEA Implementing Agreements, the International Tokamak
Physics Activity (ITPA), bilateral contracts and by providing
support and an open structure at IPP in particular for the
participation of EURATOM Associations in the AUG scientific programme. In the following, summaries for activities
in 2004 are presented (for co-operation with JET see next
chapter).
10.1 IEA Implementing Agreement and ITPA
The IEA Divertor Tokamak Implementing Agreement continued to be an effective umbrella for personnel exchanges.
In 2004, 8 scientists from IPP visited various laboratories in
the US and 5 US scientists came to IPP. Collaborative work
carried out concentrated on the following areas:
Advanced tokamak operation: The main emphasis was on
establishing scenarios with elevated, flat shear profiles, the
so-called “improved H-mode”, regime (see section 3). A
series of comparison experiments between DIII-D and AUG
was carried out. In particular, different ‘recipes’ to obtain
improved H-modes were successfully established on AUG
(including transfer of the DIII-D scenario with β feedback to
AUG) and the low q operational space was mapped out –
confirming that βN can be up to 3 without deteriorating
MHD at q95=3.
Technology and Physics of Plasma Heating Systems:
A scientist from MIT updated an existing Fokker-Planck
code for ECRH on AUG. With this code, first studies on the
generation of suprathermal electron populations under
intense ECRH were conducted. It was found that in cases
with low density and central deposition with finite toroidal injection angle a significant fraction of suprathermal
electrons can exist. Under these circumstances, quasi-linear
Fokker-Planck modelling is needed to estimate the driven
21
ASDEX Upgrade
HAS – KFKI Budapest: Four main topics of pellet-plasma
interaction have been investigated:
(i) The delay between the triggered ELM onset and the pellet ablation onset was determined and was found to be
about 50 µs for the fastest pellets. The delay time hardly
depends on the pellet mass. When the ELM signature
starts the pellet is deep in the transport barrier or even
inside of it.
(ii) An HFS pellet database was constructed using data
from 2000-2004, containing the decisive experimental
parameters of pellet-plasma interaction.
(iii) It was observed that the attached pellet cloud, which
essentially shields the pellet, moves vertically upward
about 1cm in a few µs. The drifting plasmoid, which
detaches from the cloud moves both in the radial (to
LFS) and vertical direction (upward) covering a distance of a few cm in 6 µs.
(iv) The ablation cloud of the pellet is a high β plasmoid
which extends along the field lines. Experimental observations showed that the visible radiation of the cloud is
concentrated in a small area around the pellet, which
was verified by code calculations.
Hellenic Republic – NSCR Demokritos: The reciprocating
Langmuir probe system designed and operated by the NCSR
was used to study the divertor plasma in the vicinity of the
lower X-point. For results see section 9.4.
IST – Centro de Fusao Nuclear: Several in-vessel waveguide components of the swept frequency microwave reflectometer had to be repaired and other parts of the hardware
have been refurbished. It is hoped that in 2005 the first highdensity profiles (ne~1020m-3) using the new W-band channel
will become available. Despite the hardware setbacks there
have been developments on the control & software side,
specifically implementation of frequency hopping of the
Q & V-band fluctuation channels, plus simulation tools for
plasma position control. In addition, progress has been made
in a variety of physics topics where reflectometry forms the
primary diagnostic. For example, the study of type-I ELM
dynamics and correlation of particle losses with ELM depth
(see section 9.1). Reflectometry has also contributed to the
study of type-I ELM pace making by using the magnetic
trigger approach. Contrasting the density profile evolution
and turbulence properties during triggered and naturally
occurring ELMs revealed no significant differences. The
recent implementation of IQ detection for both of the fluctuation channels has provided new insights into turbulence
behaviour during modulation of Te gradients by ECRH,
showing complex interaction between turbulence amplitude
and phase velocity/plasma rotation. In collaboration with
Kyushu University an analytic turbulence & reflectometer
simulation model has been applied to H-mode edge IQ fluctuation data in an attempt to extract rotation and absolute
turbulence levels. IST has also provided co-ordination of
MHD experiments (via TF V) and undertaken studies on
modelling TAE behaviour, which are detailed in section 8.6.
LPP-ERM/KMS, Brussels: In super conducting fusion
devices like Wendelstein 7-X and ITER, the presence of a
permanent high magnetic field will prevent the use of Glow
Discharge Conditioning (G-DC) in-between shots. ICRFDC is fully compatible with the presence of magnetic fields
and was successfully tested on two divertor-tokamaks: AUG
(in He gas) and JET (in a H2-He gas mixture) in 2003. The
2004 experiment on AUG aimed at optimising the ICRF-DC
by adding H2. Better homogeneity of RF plasmas (radial
extension towards the HFS) and significant higher antenna
coupling efficiency were achieved when the RF power
(~20 kW at f=30.0 MHz) was coupled to plasmas produced
with a gas mixture of H2/He~0.1-0.3 compared to pure He.
The addition of H2 resulted also in reduction of the averaged
energy of D and H atoms escaping from the RF plasmas
from ~4-3 keV to ~2 keV.
TEKES:
(i) Re-deposition of carbon is studied by controlled injection of 13CH4 marker gas (details in section 9.8).
(ii) The role of NBI ions on pedestal stability was assessed
with ASCOT simulations. The edge fast ion distribution
with counter-injection was found to be significantly
diffe-rent from the co-injection case. Also NBI-induced
edge currents were very different. Results for Quiescent
H-Modes are found in section 8.4.
(iii) Measurements of tungsten erosion at one of the outboard limiters of AUG suggest that fast particles play an
important role. The ASCOT-simulated fast particle
loads on the limiter are found to be in qualitative agreement with the measurements.
UKAEA: The characteristics of H-mode plasmas in a magnetic configuration with two poloidal field nulls (X-points)
were studied. A reduction in the power required to achieve
H-mode had previously been observed when the two nulls
were close to the same magnetic surface in the MAST
spherical tokamak. Experiments on AUG also showed a
reduction in the H-mode threshold power in this two null
configuration, but not as large as in MAST. UKAEA scientists also participated in a study of the radial extent and spatial structure of ELMs. A high-speed camera, which had
been used in similar studies on MAST to obtain 2D images
of the edge plasma during ELMs, was installed on the tokamak. The radial extent of the type I ELM efflux was found
to vary inversely with the toroidal magnetic field but to have
no dependence on the closeness of the plasma edge to the
wall.
22
ASDEX Upgrade
Scientific Staff
IPF University of Stuttgart: G. Gantenbein, E. Holzhauer,
W. Kasparek, T. Kubach, P. Lindner, U. Schumacher.
Humboldt Universität Berlin: W. Bohmeyer, B. Koch.
FZ Jülich: A. Kirschner, R. Wolf.
University of Potsdam: M. Abel.
ERM/KMS, Brussels, Belgium: A. Lyssoivan.
RISØ, Roskilde, Denmark: H. Bindslev, F. Meo.
UKAEA Culham, Abingdon, United Kingdom:
R. Buttery, C. Challis, G.F. Counsell, A. Kirk, H. Meyer,
M. Price.
TEKES, HUT, Espoo, Finland: V. Hynõnen, T. KurkiSuonio.
TEKES, VTT, Espoo, Finland: J. Likonen, E. VainonenAhlgren.
CEA, Cadarache, France: J. Bucalossi.
Hellanic Republic, NCSR Demokritos, Athens, Greece:
M. Tsalas, N. Tsois.
HAS, KFKI, Budapest, Hungary: G. Anda, S. Bató,
E. Belonohy, K. Gál, S. Kálvin, G. Kocsis, G. Veres,
S. Zoletnik.
DCU, University College Cork, Ireland: M. Foley,
P. McCarthy, E. Quigley, K. Sassenberg.
ENEA, IFP, CNR, Milano, Italy: S. Cirant, A. Jacchia.
ENEA, Consorzio RFX, Padua, Italy: T. Bolzonella,
M. Cavinato, R. Lorenzini, P. Martin, M. Valisa, B. Zaniol.
Riga University, Riga, Latvia: G. Zvejnieks.
IST Lisbon, Portugal: D. Borba, L. Cupido, L. Fattorini,
S. da Graca, M.-E. Manso, L. Meneses, I. Nunes, T. Ribeiro,
J. Santos, F. Serra, A. Silva, F. Silva, P. Varela.
MEC, IAP, Bucharest, Romania: C.V. Atanasiu, G. Miron.
IOFFE, St. Petersburg, Russian Federation: S.V. Lebedev.
CIEMAT, Madrid, Spain: F. Tabares.
VR, Stockholm, Sweden: S. Menmuir.
CRPP, Lausanne, Switzerland: A. Degeling, J. Lister,
Y. Martin.
EFDA Close Support Unit, Garching: A. Loarte.
Experimental Plasma Physics Division E1: N. Berger,
U. Brendel, A. Cierpka, T. Eich, H.U. Fahrbach, J. C. Fuchs,
O. Gehre, L. Giannone, O. Gruber, G. Haas, T. Härtl,
A. Herrmann, J. Hobrik, L. Horton, K. Iraschko,
M. Kaufmann, B. Kleinschwärzer, H. Kollotzek, P. T. Lang,
P. Leitenstern, K. Mank, D. Merkl, V. Mertens, H. W. Müller,
P. Müller, Y.-S. Na, J. Neuhauser, J. Neumann,
E. Oberlander, G. Prausner, G. Reichert, V. Rohde,
W. Sandmann, M. Sator, G. Schall, H.-B. Schilling,
G. Schramm, K.-H. Schuhbeck, S. Schweizer,
J. Schweinzer, H.-P. Schweiß, U. Seidel, O. Sigalov,
C. Sihler, A. Sips, J. Stober, B. Streibl, G. Tardini,
W. Treutterer, M. Troppmann, T. Vierle, S. Vorbrugg,
M. Wolf, E. Posthumus-Wolfrum.
Tokamak Physics Division: C. Angioni, M. Apostoliceanu,
G. Becker, A. Bergmann, R. Bilato, M. Brambilla,
A. Chankin, Y. Chen, D. Coster, T. Dannert, K. Dimova,
S. Günter, V. Igochine, F. Jenko, O. Kardaun, C. Konz,
K. Lackner, P. Lauber, P. Martin, P. Merkel, G. Pautasso,
A. G. Peeters, G. Pereverzev, S. Pinches, E. Poli,
W. Schneider, E. Schwarz, B. Scott, M. Spannowsky,
D. Strintzi, E. Strumberger, C. Tichmann, Q. Yu.
Experimental Plasma Physics Division E2: C. Aubanel,
K. Behler, H. Blank, A. Buhler, G.D. Conway, R. Drube,
K. Engelhardt, A. Flaws, P. Frischholz, M. García Muñoz,
L. Höllt, H. Hohenöcker, A. Keller, B. Kurzan, F. Leuterer,
A. Lohs, A. Manini, M. Maraschek, H. Meister, R. Merkel,
F. Monaco, A. Mück, M. Münich, H. Murmann, G. Neu,
M.-G. Pacco-Düchs, G. Raupp, F. Ryter, J. Schirmer,
A. Schmid, W. Suttrop, K.-H. Steuer, H. Urano, L. Urso,
D. Wagner, D. Zasche, T. Zehetbauer, H. Zohm.
Experimental Plasma Physics Division E4: K. Behringer,
R. Dux, W. Engelhardt, J. Fink, J. Gafert, J. Harhausen,
B. Heger, A. Kallenbach, C. Maggi, R. Narayanan, R. Neu,
D. Nishijima, T. Pütterich, R. Pugno, I. Radivojevic,
S.-W. Yoon.
Technology Division: W. Becker, V. Bobkov, F. Braun,
H. Faugel, P. Franzen, M. Fröschle, B. Heinemann, M. Kick,
C. Martens, J.-M. Noterdaeme, S. Obermayer, R. Riedl,
J. Schäffler, E. Speth, A. Stäbler, P. Turba, R. Wilhelm,
E. Würsching.
Garching Computer Centre: P. Heimann, J. Maier,
H. Reuter, M. Zilker.
Materials Research: M. Balden, H. Bolt, H. Greuner,
K. Krieger, S. Lindig, H. Maier, M. Mayer, J. Roth, M.Y. Ye.
Central Technical Services: F. Ascher, H. Eixenberger,
T. Franke, E. Grois, M. Huart, C. Jacob, C.-P. Käsemann,
K. Klaster, M. Kluger, J. Lex, J. Maier, H. Nguyen,
J. Perchermeier, G. Raitmeir, I. Schoenewolf, F. Stobbe,
H. Tittes, G. Zangl, F. Zeus.
IPP Greifswald: D. Hartmann, M. Laux, A. Lorenz.
23
JET Co-operation
Head: Dr. Josef Schweinzer
1 Introduction
After two short campaigns JET started a major
shutdown to install new hardware for JET-EP.
In parallel, the preparation of the 2005 JET
Programme started as well as the discussion on
a JET operation beyond 2006. IPP contributes
to all these activities.
IPP has supported the technical
improvement of the JET LH
system by a secondment to the
JET operator UKAEA. Detailed studies to separate the various causes for the enhanced
radiation in front of the LHCD
launcher were performed.
IPP has contributed to several of the JET-EP enhancement
projects including two diagnostic projects (Bolometer and
Lost Alpha Particle diagnostics) where IPP is the lead organisation. In addition, IPP supported the JET-EP project by
further secondments to the Close Support Unit, Culham and
to UKAEA. Below the main 2004 activities are described in
more detail.
The JET campaigns in the first
two months of 2004 (C13 &
C14) were characterized by experiments with low neutron
rates. Prior to the JET-EP (Enhanced Performance) shutdown, a programme with H and He, replacing D as main
gas, was run. This allowed ICRF experiments, which are less
common but of high relevance to ITER. Among those were
alpha particle simulations by accelerating 4He ions to MeV
energies using third harmonic ICRF heating and inverted
minority and mode conversion scenarios using D or 3He in H.
The 2004 shutdown will make available for future campaigns (i) a modified MkII-HD divertor which will allow
highly shaped plasmas with an input power of up to 40 MW
for 10s (ii) an improved Oct. 8 neutral beam neutralizer,
leading to a maximum of 25 MW D2 power delivered by
Oct. 4 and Oct. 8 together and (iii) new or upgraded diagnostic systems. The finalisation of the ITER-like ICRH
antenna, which is the major JET-EP hardware upgrade has to
be postponed to a shutdown in 2006.
New Task Force Leaders (TFL) for the 2005 JET campaigns
were appointed for nine Task Forces (TF). TFs S1 and M are
managed by IPP scientists.
The planning for JET operation beyond 2006 and for additional upgrades has started. IPP’s two main priorities for the
future of JET are (i) upgrading the input power so as to
allow demonstration of plasma performance in regimes as
close as possible to those foreseen for ITER and (ii) demonstration of the viability of a ITER relevant combination of
first wall and divertor materials.
2.1 Bolometer Diagnostic KB5
Two new bolometer cameras, for horizontal and vertical
views of the plasma cross section, were delivered to JET in
2004, on-time and on-budget. This work was performed on
an Article 7 contractual basis as part of JET-EP. These cameras replace previous cameras in operation (since 1985 for
the vertical camera) and represent a substantial upgrade in
capabilities. They provide more viewing chords over a larger
viewing angle, higher detectable energy range, higher sensitivity, lower noise level and therefore lower detectable signal
(~1 µW/cm2 for t=2 ms vs. ~70 µW/cm2 for t=20 ms).
Definition of the lines-of-sight is attained by a collimator
arrangement for the vertical camera and use of pinholes for
the horizontal camera. Each camera is comprised of 24
channels, vs. 8 for the previous vertical camera and 20 for
the horizontal. Of these 24, 8 channels are allocated to the
divertor region, yielding a spatial resolution of ~8 cm. Thus,
for the first time it is now possible to adequately characterize the divertor radiation patterns in JET.
2 IPP’s Contributions
The detectors are essentially the same as those on AUG
(gold energy-absorbing layer, 20 µ mica substrate, ~1.2
kohm gold meander), whereby the absorber layer has been
increased in thickness from 4 to 8 µ in order to extend sensitivity to 8 keV. The JET bolometer electronic units have
been modified or replaced so as to provide a 40 V p-p bridge
voltage at a carrier frequency of 50 kHz (vs. 10 V dc) in
order to permit use of synchronous demodulation techniques. These factors, in combination with an improved
shielding concept, are responsible for the dramatic improvement in the signal/noise ratio.
IPP provided TFLs for TF H, M and S1 for the 2004 campaigns. They were strongly involved in the execution of C13
& C14, the subsequent analysis of experiments and the
preparation of publications and conference contributions.
The majority of this work was performed at JET.
In April a TF H meeting at Ringberg Castle gathered up to
50 international participants, to plan for 2005 and to conclude the analysis of the past experiments. The topics
addressed were: the heating, current drive and rotation
physics, the launching and deposition issues and the optimisation of the systems (ICRF, LH, NBI). The JET-EP ITERlike antenna and related heating enhancements were
reviewed. IPP supported the JET-EP ITER-like antenna
project through membership in the Project Board, computer
calculations and knowledge transfer (e.g. on arc detection
systems).
2.2 Lost Alpha Particle Diagnostic – Scintillator Probe
The measurement of energetic particle losses and the investigation of the underlying processes is the aim of a new diagnostic, which consists of Faraday cups and of a scintillator
probe. IPP is responsible for the latter.
25
JET Co-operation
The main components are a long Inconel 625 shaft installed
in a limiter guide tube, an actively cooled probe head –
housing the scintillator (P56) – and an integrated optical
imaging system. Time dependent finite element calculations
revealed that even a tiny clearance of a few mm between the
probe shaft and the limiter guide tube results in forces during a disruption of more than 30 tons. A new solution, based
on spring washers closing the gap, reduces these forces to
approximately 5 tons. Due to the unavoidable proximity of
the probe tip to the plasma edge and the NBI next to the
diagnostic, strong heat loads on the probe tip are expected.
Therefore, the probe tip is thermally protected by a CFC
cup. Its design accounts for intersection with free ion orbits
as well as for tangentially impinging magnetic field lines in
order to distribute the heat load over a wide surface area.
Thus, the final design was defined by means of orbit simulations (W7, EfipDesign) and finite element structural, electromagnetic and thermal analysis (ANSYS). These simulations also revealed that in some cases particles get
scraped-off on obstacles between the two adjacent poloidal
limiters, like the TAE antennas, which will reduce the signal.
The assembly of the scintillator probe started in the middle
of 2004. A major effort in this period has been made in
meeting the high quality requirements of JET. The diagnostic is now ready for installation in early 2005.
2.3 Plasma Edge Code Benchmarks
Within the framework of EFDA JET, a code-code benchmark activity has been launched to compare SOLPS B2EIRENE and EDGE2D-NIMBUS. Initial large differences
for the base case (pure D, no drifts) was traced to differing
assumptions about parallel heat flux limits, target sheath
parallel velocities and gas puff locations. With these issues
resolved, the two codes produced very similar results for
both upstream and downstream temperatures and densities,
see figure.
2.4 Development of ASTRA / JAMS interface
The transport code ASTRA (IPP) has been integrated into
the JAMS Graphical User Interface that was developed at
JET and incorporates also other transport codes like
CRONOS (CEA) and JETTO (UKAEA). As a result of the
integration, all three codes have now a common input/output, thus allowing the use of all JET pre-processing and
post-processing tools and a direct comparison. Benchmarking of ASTRA, CRONOS and JETTO has started. The
possibility to operate ASTRA in an interactive mode turned
out to be of advantage for predictive modelling studies in
comparison to the pure batch job based operation of the
other codes.
2.5 Micro Wave Access
EM simulation of different waveguide options were performed, in particular their radiation characteristics when
used as antennas. Corrugated waveguides turned out to be
not only the best option for long distance low loss signal
transmission, but also to be very efficient front end antennas. Radiation pattern of the open-ended smooth waveguide
for ECE measurements have been analysed. Cross check
calculations on different horn antenna designs for the quasioptical coupling blocks, used to connect the oversized corrugated waveguides to fundamental waveguides, were done. It
could be shown that an improved nonlinear horn antenna
cannot satisfy the bandwidth requirements of the system
(60-160 GHz) and therefore a linear design is the best solution.
Scientific Staff
C. Angioni, S. Bäumel, R. Bilato, V. Bobkov, F. Braun,
A. Chankin, D. P. Coster, T. Eich, H. Falter, J. Fink,
C. Fuchs, J. Gafert, J. Hobirk, L.D. Horton, A. Kallenbach,
M. Kaufmann, K. Kirov, K. Krieger, P. T. Lang, A. Lorenz,
M. Mayer, M. Maraschek, K. McCormick, Y-S. Na, R. Neu,
J-M. Noterdaeme, G. Pereverzev, S.D. Pinches, J. Roth,
F. Ryter, A. C. C. Sips, A. Stäbler, J. K. Stober, W. Suttrop,
D. Wagner, A. Werner, W. Zeidner
Results of the code-code benchmark shows good agreement between
SOLPS B2-EIRENE and EDGE2D-NIMBUS.
26
Stellarator Research
WENDELSTEIN 7-X
Head: Prof. Friedrich Wagner
1 Introduction
In 2004, the project Wendelstein 7-X has
entered into a transition from the design and
construction phase towards the assembly phase.
Although new technical problems came up during the year, manufacturing of the components
has progressed well and the first components
have been delivered to Greifswald, including
the first non-planar coil. In 2004 the project
was restructured and the personnel resources
attributed to Wendelstein 7-X were strongly
increased.
and for archiving all documents
relevant to the project (i.e. MS
Office documents as well as all
CAD-models and drawings). In
2004 the preliminary, Excelbased, documentation system
has been replaced by a commercial electronic documentation system, the Eigner Product
Lifecycle Management System
(PLM). In a first step this system has been put into operation
for the Office documents, the
administration of the CAD models (in CADDS5-format),
is being implemented.
On 1 January 2004, the project
Wendelstein 7-X has been reorganized as shown in figure 1.
The project has been established as a ressort within the
board of directors and now is
composed of five sub-divisions.
At the same time (partially only
later during the first quarter of
2004), seven persons from Garching and 88 further staff from
the divisions E3, E5, Technology, Plasma Diagnostics and
Technical Services have been transferred or seconded into
the project. During the year 3 scientists from the EFDA
Team joined the project. On 31 December 2004, 210 people
worked in the project.
In 2004 design and manufacturing of the different machine
components of the basic device has progressed considerably,
as described in chapter 2. This was accompanied by a strong
engineering effort from the newly established subdivision
System Engineering (chapter 3). In parallel to the development of the basic components, assembly of the stellarator
has been prepared with respect to the assembly technology
and the assembly procedures and with trials using dummy
parts or the first components delivered to Greifswald as
described in chapter 4. The development of the diagnostics
(chapter 5), the heating systems (chapter 6) and the control
system have been concentrated into the subdivision Physics.
1.2 Schedule
According to the present planning it is expected to start the
commissioning of W7-X in 2010. Due to the delivery delay
of components the assembly could not start in the first half
of 2004, but will start in March 2005. Some modification of
already finalised assembly methods (e. g. for elements of the
inter-coil support structure, Narrow Support Elements and
Lateral Support Elements) may influence the existing schedule. Reliable estimations, however, are only possible after
having the experience of the first half-module assemblies.
2 Basic Device
2.1 Magnet System
The main components of the magnet system are the superconducting coils, the coil support structure, the inter-coil
supports, the superconducting bus system, the current leads
and the power supplies for the coils.
1.1 Project Coordination
This subdivision comprises four departments dealing with
coordination activities for the project W7-X:
– Project Control is responsible for the financial planning of
the project and for control of the expenditures, time planning of all the activities in the project as well as of the
external contracts, support of the component responsibles
in handling their industry contracts as well as organisational aspects of the project and the reporting to all external supervising bodies (committees).
– System Coordination coordinates general technical aspects
such as interface control, configuration management, technical specifications (of the device as such as well as of its components), safety aspects and material questions.
– Quality Management is organising the QM system within
the project W7-X and supports all external contracts concerning QM aspects. This department has been increased
considerably in 2004 to enable the group also to take some
responsibility in quality assurance during the assembly
phase of W7-X.
– The Documentation department is responsible for an independent check of all technical drawings and CAD-models
2.1.1 Superconductor
The superconductor for the coils is composed of 243 NbTi
strands wound to a cable and enclosed by an aluminium jacket. By the end of 2004 the EAS/OCSI (formerly VAC/EM)
consortium has delivered 347 out of 360 required conductors
with typical lengths between 120 and 180 m. Some conductors showed broken strands. Following experimental investigations at the Paul Scherrer Institute a maximum of one broken strand every 50 m could be accepted, provided that these
conductors are only used for the outer turns, which operate at
a reduced magnetic field. Twenty-four additional conductor
lengths have been ordered as spares.
2.1.2 Superconducting Coils
The non-planar coils are being manufactured by the
Babcock-Noell Nuclear (BNN)/Ansaldo Superconduttori
consortium. Winding of the coils is being performed in parallel on three winding lines at Ansaldo and two winding
29
WENDELSTEIN 7-X
lines at BNN’s subcontractor, ABB. By the end of 2004, 38
winding packages have been delivered for coil assembly and
additional eight are in different stages of production. The
Swedish subcontractor, Österby Gjuteri AB, cast and
machined 80 (out of 100) half-shells of the coil casings from
316 LN stainless steel. Forty-four of them have already been
used in the coil assembly. The cast material is very good in
terms of castability and weldability, mechanical behaviour at
cryogenic temperatures and geometrical tolerances. During
inspections with a linear accelerator (LINAC) casting failures such as shrinkages, pores and cracks were, however,
discovered in areas, which have not been accessible to the
standard X-ray inspection method before. It was then decided to inspect all remaining casings, extensions and 21 coils,
which were already embedded, by the LINAC method. A
joint working group was set-up to decide in which cases a
defect required repair or could be tolerated. Integration of
all non-planar coils is being done at BNN’s production site
at Zeitz. First the winding package is positioned between the
two halves of the steel casings using four reference pins on
each side of the winding package. Next the winding package
is embedded in quartz sand and epoxy resin. During injection of the quartz sand the casing is heated to approx.
100 °C, while the winding package is kept at ambient temperature. During re-cooling of the casing the winding package is pre-stressed. This pre-stress will be released during
operation at cryogenic temperature due to the different thermal contraction of the casing and the winding package.
After embedding, the coil casing and the interface areas are
machined to the required precision on a five-axis CNC
machine. This operation takes place at the company PEM in
Schwarzenberg. During a subsequent survey the positions of
the coil fixtures and reference pins and the contour of the
surface of the casing are checked against the CAD model.
Figure 1: Organigramme of the Wendelstein 7-X project as of 31 December 2004
30
WENDELSTEIN 7-X
The accuracy achieved is within 0.5 mm for the reference
pins and coil fixtures, 2 mm for the inner surface and 5 mm
for the outer surface of the casings. Finally, the cooling systems are mounted onto the casings. This involves covering
the surface of the casing with strips of highly conductive
copper soldered to the cooling loops and welded to the casing. The copper strips reduce eddy current heating of the
coils in case of a rapid shut-down of the magnet system.
Finally, temperature and strain sensors are installed. Each
coil is checked against quenches by several voltage tabs connected to the conductor jacket and routed through the cryostat via special high-voltage quench detection cables.
During the acceptance tests of the first coils it turned out
that these cables were not sufficiently proof against high
voltage in a vacuum environment. A new cable was designed
with improved insulation. The qualification process of the
cables included a life cycle high-voltage test at 17 kV DC
and 8 kV AC and a high-voltage test at low temperatures. To
connect the new cable to the remaining parts of the old
cable, special connectors were designed and qualified. All
coils have to pass a work acceptance test at BNN including a
pressure and flow test, an integral leak test in a vacuum
chamber and a check of the electrical insulation by a static
test at 13 kV DC as well as at ±2 kV AC in air at ambient
pressure. During operation, however, the coils could experience a situation where the high voltage develops during a
simultaneous loss of the insulation vacuum. In the worst
case the coil would pass the Paschen minimum, which is
characterised by a minimum break-down voltage of about
150 V at pressures between 0.1 and 100 mbar. Therefore it
was decided to perform an additional high-voltage test of
the coils at reduced pressure. Tests with the first coil showed
partial discharges in the coil termination area at voltages
around 2 kV at pressures between 1 and 100 mbar.
As a consequence of detailed structural calculations the connections of the coils to the support structure as well as the
interfaces between the coils and the inter-coil support elements had to be modified. This required reinforcement of
the welds on the coil support elements, an increase of the
number and size of the threads for the bolts and re-machining of those areas where the coils contact each other along
the inner side of the casing. Implementation of the new
design required to re-work ten coils which were already
largely finished. The work is in full progress and the first
coil was delivered to Greifswald for assembly on 30
December 2004. Manufacture of the 20 planar coils at Tesla
Engineering was continued. By the end of 2004 all twenty
winding packages have been produced and nine were
embedded in the casings and finished (see figure 2). As with
the non-planar coils, the quench detection wires turned out
not to withstand the specified high voltage and had to be requalified and exchanged. During re-testing of some finished
coils at Saclay (see chapter 2.1.3) severe leaks were detect-
ed. One of the leaks could be attributed to a crack in the
steel pipe of the helium cooling loop of the casing. From
microscopic investigations it was concluded that residuals of
an aggressive flux, which was used during soldering of the
tube, have caused corrosion cracking of the thin-walled steel
pipe. It was decided to replace all cooling tubes by tubes
with a larger wall thickness and to change the soldering
technique to avoid corrosion. Since the leak testing and
metrology facilities of Tesla are not sensitive enough, IPP is
performing these quality checks by its own at Tesla’s premises. Integral leak testing is being done using SF6 as a tracer
gas. Leaking gas is accumulated in a plastic bag around the
coil and detected by laser spectroscopy. To check the welds
in the termination area with higher sensitivity local vacuum
chambers and standard helium leak testing are applied.
Surveys of the coil connections, the positions of the reference pins and the contour of the casings are routinely be performed by JET experts by digital photogrammetry.
Figure 2: Planar coil during assembly trials
2.1.3 Coil Tests
After production all superconducting coils are tested under
operational conditions at the Low Temperature Laboratory
of Commissariat à L’Énergie Atomique (CEA) in Saclay.
Meanwhile, four non-planar and five planar coils were tested. The electromagnetic tests have been passed without
problems. Quenches occurred at slightly higher temperatures than predicted giving some additional margin for the
future operation of these coils. Two planar coils showed
large cold leaks in the termination area during cool-down,
while a third one showed a leak in the casing cooling system
during testing at room temperature (see above).
2.1.4 Coil Support Structure
The coil support structure is being manufactured by the
Spanish contractor, Equipos Nucleares, S.A. (ENSA), and
consists of ten identical sectors with a total weight of 72 t,
which span a central pentagon. Ten cylindrical supports
31
WENDELSTEIN 7-X
carry the weight of the support structure and provide the
thermal barrier between the cold structure and the machine
base. The coil support structure is made of steel plates and
cast steel extensions for the coil fixtures. As a result of a
structural analysis the support ring was stiffened in some
areas and the coil connection blocks were modified to cope
with the larger number and increased size of high-strength
bolts. Special tensioners with improved performances
(“superbolts”) have been successfully tested on mock-up
connections to verify that the necessary high pre-loading
can be applied. Inconel 718 has been selected for these highloaded connections. In a further test campaign an assembly
of three bolts will be subjected to the design loads in a cryovacuum environment. The interfaces of the sectors of the
coil support structure will be precision machined and joined
by bolts. Final tightening of the bolts between different
modules of the support structure will only occur when a
symmetric alignment of all W7-X modules during final
assembly of the torus is made. This requires precisely
machined inter-layers between the sectors of the coil support
structure. The coil support structure will be cooled by supercritical liquid helium. To provide good heat transfer from the
steel structure to the helium cooling pipes, copper coated
stainless steel pipes are soldered to copper blocks which are
again brazed to the steel structure. The high-temperature
brazing of the copper blocks which happened already in a
previous manufacturing step had unfortunately caused
cracks at the surface of the cast material of the steel extensions. In the second half of 2004 a repair procedure for the
steel blocks has been defined and qualified. The repair
activities are now in progress. Qualification tests for the new
process for the attachment of the cooling tube have been
successfully performed and are being finalised. To minimise
the delay caused by the faults in the extensions and the
maintenance of the machining plant the production plan has
been critically reviewed and optimised resulting in parallel
manufacturing, modification of the sequence of actions and
subcontracting of machining activities. The first module
shall be delivered to Greifswald in autumn of next year
which is still compatible with the assembly schedule.
of the bus-bar rounding was completed successfully. The
qualification of the bus-bar insulation and of the joint-insulation started. The manufacturing equipment was ordered,
the manufacturing area at FZJ is completely prepared. A
simplified but still very complex 1:1 manufacturing template of a module was put in operation. The template is used
to pre-install and to survey more than 125, up to 14 m long,
single bus-bars. Almost all the needed superconductor material for the bus-bars was procured. The aluminium welding
procedure between superconductor jacket and joint-transition pieces was successfully qualified. Approximately 400
of those welds have to be made during the assembly.
2.1.7 Current Leads
Fourteen current leads each able to carry 20 kA connect the
seven groups of superconducting coils with the corresponding power supplies. The current leads are designed in the
conventional way but for a lower than nominal current and
hence are operated somewhat overloaded during nominal
operation of the magnet system. In this way the heat conduction along the current leads and hence the cooling requirements are reduced during stand-by periods. In 2004 the
design was improved to better suit the needs of W7-X.
Procurement of the current leads shall start in spring 2005.
All current leads shall be tested at operational conditions
prior to assembly.
2.1.8 Magnet Power Supply
The five types of non-planar and two types of planar coils
are energised by power supplies providing direct currents of
up to 20 kA at voltages of less than 30 V. The Swiss contractor, ABB, selected the concept of twelve-pulse rectifiers to
ensure that the currents are stabilised with an accuracy of
2x10-3. Fast and reliable discharge of the superconducting
magnets in case of quenching is realised by a fast circuit
which short-circuits the coils and dumps the magnet energy
to nickel resistors. In 2004 all seven power supply units were
installed and individually commissioned and accepted. The
concept of the quench detection electronics was further
worked out in co-operation with experts from FZK.
An extensive R&D program has been performed to develop
the inter-coil supports. The supports between the planar and
non-planar coils have been re-designed to allow mechanical
attachment and removal during assembly and to allow precise machining of the matching parts after the coils are
adjusted. The design is in its final stage and the procurement
contracts are planned for the beginning of 2005.
2.2 Cryostat
The cryostat consists of the plasma vessel, the outer vessel,
the ports and the thermal protection. It provides the thermal
insulation for the magnet system and gives access to the
plasma. Deggendorfer Werft und Eisenbau GmbH
(MAN DWE) are responsible for manufacturing the plasma
vessel, the outer vessel and the thermal insulation. The ports
are manufactured by the company, Romabau Gerinox.
2.1.6 Bus System
2.2.1 Plasma vessel
The co-operation with the FZ Jülich was extended. The
qualification of the 170 bar joint-housing (prototyping) and
The plasma vessel is composed of ten half-modules. Each
half-module is cut into two sectors to allow stringing of the
2.1.5 Inter-coil Supports
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WENDELSTEIN 7-X
innermost coil during assembly. The complex shape of the
plasma vessel follows the 3D shape of the plasma boundary
and is manufactured from 200 precisely bent and welded
steel rings. Between all major steps of manufacture, compliance with the narrow tolerances of the vessel is controlled
by laser tracking metrology. Vacuum tightness of the welds
is checked by an integral helium leak test of the vessel segments. Precise cutting of the holes for the ports is performed
by the water jet technique. The water jet was also used to
mark the routing of the saddle coils as well as of other coils
for the magnetic diagnostic. Water pipes are welded around
the plasma vessel to allow control of its temperature during
plasma operation and bake-out. In 2004 the routing of the
water pipes had to be modified to give more space to the
Rogowski coils. By the end of 2004, all 200 steel rings have
been produced, the main bodies of four half-modules are
ready (see figure 3) and the four sectors of the first two
modules have been delivered for assembly.
2004 160 round and oval ports were delivered. During the
leak test of one large rectangular port a small leak on the
Helicoflex seal was detected. IPP is working with the supplier to solve the problem. All holding devices for the round
and rectangular ports are produced and were delivered for
assembly trials.
2.2.4 Thermal insulation
MAN DWE GmbH
Efficient insulation of the cold magnet system requires careful protection against heat conduction and radiation for
which high vacuum, actively cooled thermal shields, and
multi-layers of reflecting metallic foils are used. By these
means the thermal losses can be kept below 1.5 W/m2. The
shields are cooled at temperatures between 40 K and 70 K
by cold helium gas. MAN DWE joined with Linde AG as
subcontractor for the cryogenic layout, development and
assembly. Different design requirements apply to the thermal insulation around the plasma vessel, along the inside of
the outer vessel and around the ports. The basic concept for
all areas is the same and consists of 20 layers of multi-layer
insulation (MLI) which are covered by an actively cooled
thermal shield. The shield around the plasma vessel must
have a low electrical conductivity to limit eddy currents in
case of a rapid shut-down of the magnets. Therefore the
shields were manufactured from glass epoxy resin panels
instead of conventional metal sheet. This novel design
allows much easier producibility and better shape accuracy.
Three layers of copper meshes inside the laminated glass
epoxy resin panels ensure sufficient thermal conductivity.
Each mesh is intersected to reduce eddy currents. To cover
one plasma vessel half-module requires twenty such shield
panels with corresponding MLI panels attached to them.
Each shield panel is cooled by two helium tubes. The thermal emissivity of the panel surfaces which face the cold
coils is reduced by adhesive aluminium tape. The shields are
fixed to the plasma vessel by Torlon supports which are
designed for low heat conduction and high strength. The
MLI of the plasma vessel is made of aluminised crinkled
polyimid (Kapton®) foils with glass fabric in between.
Crinkled Kapton® foils have excellent insulation properties
and can be adapted very well to the complicated vessel surface. The specified thermodynamical, electrodynamical and
mechanical performance of the thermal insulation was confirmed by accompanying finite element analyses and tests.
Tests of non-compressed MLI samples consisting of 20 layers resulted in extremely low losses of 0.67 W/m2. Losses of
0.93 W/m2 were measured for a compressed MLI sample
with overlaps representing realistic interfaces. The first
insulation segment was mounted to the first sector of the
half module of the plasma vessel in summer 2004 (see figure 4). The next segments are ready for assembly and will
be mounted after stringing of the first coil. Currently the
thermal insulation of the ports is being developed.
Figure 3: The last steel ring and sectors of the plasma vessel in different
stages of production
2.2.2 Outer vessel
The outer vessel of W7-X is assembled from five lower and
upper half-shells. Following detailed structural analysis
some ports which will hold flanges had to be modified.
Cutting of the openings of the first half-shell has been completed with the required precision. The domes of the first
half-shell have been produced and are being welded to the
shell. To allow final symmetric alignment of the W7-X modules a fitting ring will be used between the modules of the
outer vessel.
2.2.3 Ports
A total of 299 ports are used for evacuating the plasma vessel for plasma diagnostics and plasma heating and for routing supply lines and sensor cables. All ports are surrounded
by water pipes to control their temperature. At the end of
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WENDELSTEIN 7-X
facing surfaces have to be covered with low-Z material. The
target plates are armoured by CFC tiles, the baffles are covered by graphite tiles and the wall protection shall be coated
with boron carbide.
2.3.1 Target plates
MAN DWE GmbH
Each of the ten divertor targets is split into two sections
designed to withstand heat loads of up to 10 MWm -2 separated by a section designed to withstand convective heat
loads of 1 MWm-2 only. The high-loaded target elements
consist of precipitation-hardened CuCrZr alloy heat sinks
armoured with tiles of SEPCARB® NB31 carbon fibre composite produced by SNECMA Propulsion Solide, France.
Plansee has performed and finished a comprehensive qualification programme to verify joining the CFC tiles to the
CuCrZr heat sink using the active metal casting technique
(AMC®) and electron beam welding. Four target elements
were subjected to an electron beam with a power density of
10 MW/m2 without damage in the Jülich facility Judith.
Investigations have been started to detect defects in the
bonding by infrared thermography. In 2004 SNECMA manufactured the main batch of 1150 blocks of CFC type NB31.
Characterisation of the material by SNECMA and by
Forschungszentrum Jülich revealed that the mechanical
strength fell short and reached only 60 % of the specified
value. Although the thermal conductivity is within the specification it is nevertheless reduced against the values
achieved during prototype production. Also the density is
not uniform. The reasons for these discrepancies are still
under discussion. Plansee will re-assess the joining process
to check whether the delivered material can still be used.
The target elements are supplied in parallel within each
module by a central cooling water line with a diameter of
40 mm. Bellows in the pipes avoid thermally induced stresses. The worst failure is expected if during bake out of the
plasma vessel one of the supply pipes would rupture. The
consequences are currently investigated to derive the design
parameters for the safety device for the plasma vessel.
Figure 4: Mounting of a panel of the thermal insulation on the plasma
vessel
Especially the interfaces to the plasma vessel and to the
outer vessel need to be carefully designed to block stray
radiation. Design of these interfaces has also to consider the
narrow space and the need to compensate relative movements between the two vessels of up to 30 mm, respectively.
A prototype port insulation was built which demonstrated
the suitability of the chosen concept.
2.3 In-vessel Components
The in-vessel components comprise divertor target plates
and baffles for energy and particle control, panels and heat
shields to protect the wall against plasma radiation, control
coils to modify the magnetic configuration at the plasma
boundary, water supply lines for heat removal, and cryopumps to control the neutral gas density during high-density
plasma operation. In order to protect the cryo-pumps behind
the target plates, protective shields are required. Plansee has
been awarded the contract for the target elements, MAN
DWE for the wall protection panels and BNN for the control
coils. Assembly of the target modules from target elements
as well as fabrication of the baffles, the heat shields, the
cryo-pumps and of the supply lines will be performed by
IPP. The heat loads to the components facing the plasma are
quite different: The divertor target plates are hit predominantly by hot particles from the plasma and have to withstand heat loads of up to 10 MW/m2. Baffles, which influence the fluxes and density of neutralised particles in front
of the target plates and which improve the pumping efficiency, need to be designed for a heat load of 0.5 MW/m2. The
wall of the plasma vessel mostly interacts with neutral particles and radiation from the plasma boundary and has to be
protected against heat loads of up to 0.3 MW/m2. The sections of the ports close to the plasma may be reached by
radiation up to 100 kW/m2. To keep the reflux of impurities
from the wall to the plasma at acceptable limits all plasma-
2.3.2 Baffles
The design of the baffles, of intermediate target elements
with reduced load, and of the heat shields on the inner side
of the wall which require a strong heat protection is based on
CuCrZr heat sinks with clamped graphite tiles. Brazing of
the stainless steel cooling tubes into the CuCrZr requires a
rapid cool-down of the materials to maintain its hardness
and thermal conductivity. The major part of the wall with an
area of about 70 m2 will be protected by double-walled steel
panels with integrated cooling loop. They are designed to
withstand heat loads of 0.1 MWm-2 stationary and
0.2 MWm-2 transient. MAN DWE has fabricated prototype
panels of the wall protection (see figure 5), which have
passed the tests successfully. Slits between the panels have
34
WENDELSTEIN 7-X
to be kept as small as possible to avoid thermal overload of
the underlying wall of the plasma vessel. The protection baffles of the ports have been postponed and will be installed
only after a first operational phase of W7-X.
has been successfully tested at IPP under mechanical loads,
a pressure of 40 bars and nominal current. Each coil can be
individually supplied with direct currents of up to 3 kA at
voltages of up to 30 V which can be modulated at frequencies of up to 20 Hz by dedicated power supplies. All ten
power supplies have been delivered and commissioned by
the Spanish contractor, JEMA. During the combined test
unexpected oscillations have been observed which require
filtering.
2.4 Refrigeration System
The refrigeration system has an equivalent capacity of 7 kW
at 4.5 K to supply the magnet system with supercritical helium at different temperatures and provide liquid helium to
the current leads and to the divertor cryo-pumps. The refrigeration concept takes into account that the superconducting
coils will be energised only for about 700 hours per year at
nominal current and only for about 50 hours per year at
maximum current. During the remaining time the plant is in
different standby modes. As a consequence, the refrigeration
requirements of W7-X vary considerably. To allow economic operation the excess plant capacity during standby modes
(e. g. overnight) will be used to liquefy helium into a
10,000 l storage tank. During W7-X operation helium is
taken from the storage tank to boost the refrigeration power.
Linde Kryotechnik AG, Switzerland will deliver the complete helium refrigeration system, comprising the compressors, the helium purification system, the cold box with
expansion turbines and cold compressors, the sub-cooler
with helium circulation pumps, the cryogenic transfer lines
between the refrigerator and W7-X, and the coolant distribution valve box. The contract runs according to schedule. The
basic process layout of the plant and the control concept are
finished and site planning has started. Quality and project
management procedures are established and in action. Detail
design and procurement of the main components have started. The liquid nitrogen system of the branch institute consists of a 30,000 l tank and a distribution system. In 2004
approx. 57,000 l of liquid nitrogen were provided for the
ECRH system, the cryo-laboratory and other users within
the institute.
Figure 5: Prototype wall protection panel
2.3.3 Pumping
Vacuum pumps are required to evacuate the plasma vessel,
to control the density of auxiliary gases injected into the
divertor chamber and to pump out neutral particles.
Additional cryo-pumps behind the divertor allow the pumping capacity to be increased in particular for helium and
deuterium during high-density plasma discharges. The cryopumps are composed of a cryo-panel cooled with liquid
helium, a Chevron baffle, a reflector cooled with liquid
nitrogen and an additional water cooled baffle. Two cryopump units will be placed behind the horizontal targets of
each divertor. The lay-out and the basic design of the cryopumps have been completed.
2.3.4 Control Coils
Ten copper coils will be installed in the plasma vessel
behind the baffle plates to correct minor field errors, influence the extent and location of the magnetic islands, and
allow the power deposition area to be swept across the target
plates. The control coils have dimensions of 2x0.3 m2 and
are wound by 8 turns of a hollow copper conductor cooled
by water. BNN has been awarded the contract in 2004 and
has finished the detail design and performed manufacturing
trials. Winding of a double pancake can be performed in one
process by winding the first pancake from outside to inside
thus avoiding brazed connections at the cross-over between
the two pancakes. Special emphasis is put on the design of
the current leads of the control coils because they are subjected to high electromagnetic forces in a perpendicular
magnetic field of about 3 T. A prototype of a current lead
35
WENDELSTEIN 7-X
3 System Engineering
ring, the connection between adjacent coils (lateral, contact,
planar and narrow supports) as well as the He cooling circuits, the connection headers and the constriction areas,
where the adjacent coil casings are only a few millimetres
apart from each other. Additional correction coils, situated
on the outer vessel, have been investigated. The compatibility of the plasma vessel as-built geometry was verified with
respect to adjacent components (thermal insulation shield,
coils). The plasma vessel vertical supports were redesigned.
The design of the divertor and other in-vessel components,
such as targets, baffles and the first wall shields are in
progress. For the diagnostics, the attention concentrated on
the design of the Rogowski coils, the saddle coils, the diamagnetic loop, Thomson scattering interferometer, bolometer and neutral gas manometers. Furthermore Design Office
staff members supervise the progress and results of contracts placed with collaborating institutes, universities and
industry. Advanced technologies like laser scanning, reverse
engineering, rapid prototyping and an unique procedure for
Finite Element deformations fed back into the CAD model,
as well as various proprietary developed software has been
utilised to accomplish the technological requirements.
In addition to the tasks described in the following chapters,
this subdivision started in 2004 to conduct a series of design
reviews for different components and tasks of W7-X:
– Plasma Vessel and Ports
– Magnetic Measurements, Thermal Insulation, Outer Vessel
– Planar Coils, Non-planar Coils, Coil Support Structure,
Inter-Coil Support Structure
– Busbar system and machine assembly
– Metrology
– In-Vessel Components
For all these 2-3 day meetings external experts were invited
to advise the project on potential problems, possible modifications and improvements. Further design reviews are
planned for 2005.
3.1 Design Office
Task of the department is the support in design and development of experimental components for the W7-X enterprise,
predominantly by use of CAD software (see figure 6). Main
focus of tasks was dedicated to design and manufacturing
issues of the basic components of W7-X: the coil system,
the central support ring, the busbar system, the plasma vessel, the divertor and various startup diagnostics. Major effort
was put on the W7-X detailed design with special attention
given to the collision analysis of components whilst assembly and operation with respect to their as-built geometry.
The coil system, consisting of 20 planar coils (2 types) and
50 non-planar coils (5 types) was analysed and reviewed – in
particular with respect to the fixation on the central support
3.2 Design Engineering
The main analysis efforts have been addressed to the components, which are critical due to the fabrication schedule.
An in-house global FE model (using the ADINA code) is
considered as a tool for identification of critical components
and a source of forces and moments for detailed local analyses, which have been performed within a wide collaboration
with external experts. The original FE ADINA model has
been subjected to considerable modifications to reflect an
evolution of the magnet mechanical structure. The paramet-
Figure 7: finite Element ANSYS model of magnet system semi-module
(36-degree)
Figure 6: CAD view of Wendelstein 7-X
36
WENDELSTEIN 7-X
ric analysis of initial gaps between Narrow Support (NS)
Elements results in a choice of a preferable clearance distribution between NS facing elements. The gaps vary from 0.2
to 4.5 mm and provide moderate stress level in the components with a maximum displacement of the non-planar coil
of about 17 mm in the Low Iota Scenario. In order to have
confidence in the global analysis of the magnet system, an
independent FE ANSYS model of a semi-module has been
created in collaboration with the Efremov Institute, Russian
Federation, see figure 7. The most critical NS and Central
Support (CS) Elements have been analyzed in detail in collaboration with FZJ, and Warsaw Technical University,
Poland, see figure 8. The refined analyses include the effects
of material plasticity and contact/sliding effects.
The study of combined behaviour of the plasma vessel, the
outer vessel and the vessel support system including the
basic machine is important for both the assembly and operation. The creation of a global FE model consisting of these
components has been initiated.
2 mm. Only the statistical deviations generate error field
components with different periodicity than five, the systematic deviations only add negligible field components.
Assuming that the remaining winding packages will show
statistical deviations in the same range, the dominant
Fourier components of the error fields ∆B11/B00 and
∆B22/B00 would contribute to the field errors with fractions of 0.59⋅10-4 and 0.62⋅10-4 respectively. Compensation of field errors could be achieved by active coils.
In W7-X 10 control coils will be installed close to the
divertor modules to optimise the magnetic configuration.
They can also be used for error field compensation.
However, their capability with respect to the B 11 Fourier
component is too low. Therefore an additional set of correction coils is planned. For the generation of B11 and
small B22 components it is sufficient to install five correction coils (one per field period) on the outer vessel – each
of them with a current capability of 100 kA-turns.
– Magnetic stray field calculations for different users.
– Investigation of magnetic field perturbations due to ferromagnetic materials: The utilisation of materials with
increased magnetic susceptibility (µr>1) is kept under control. For the wall and port protection panels slightly
increased values of the magnetic permeability were
accepted because of their relatively small impact on field
perturbations. With a statistic distribution of 1.0<µr<1.05
the magnetic field perturbation is lower than 1·10-5 for the
relevant field components.
– Additional magnetic force calculations of the coil system
for different load cases.
– Analysis of maximum magnetic field values inside the coil
winding packages.
– Computation of magnetic force distribution in the bus-bar
system.
– Analysis of magnetic fields and power loads concerning
the divertor design.
Figure 8: finite Element ANSYS model of Central Support
3.4 System Integration
The main activities launched have been the following:
– System lay-out studies related to the W7-X components in
the torus hall: It is important to carry out lay-out studies to
detect and solve collision problems as soon as they arise,
to optimise routing of pipelines and cable lines, supports
and to check accessibility for repairing and/or maintenance. Such activities have been started in the last months
of 2004. First steps have been: collection and organisation
of the existing information, identification and prioritisation of the existing lay-out issues (see figure 9).
– Co-ordination of mechanical tests of some critical magnet
system connection elements (see also chapter 3.2).
– Mechanical instrumentation of W7-X. During operation,
the mechanical behaviour of the basic machine (coils, vessels and support structures) will have to be monitored by
3.3 Electromagnetic Calculations
The following activities have been carried out:
– Analysis of magnetic field perturbations caused by manufacturing and assembly errors and design of a correction
coil system: In particular by the end of the year 2004 35
out of 50 non-planar winding packages were analysed and
13 packages out of 20 planar coils. Their shapes are surveyed by measuring eight points at the four sides of the 96
cross sections along their circumference. The data show
systematic deviations to the nominal geometry and statistical deviations from the centre current filament geometry
of all investigated winding packages of the same type.
These centre current filaments of 48 analysed non-planar
and planar winding packages show average deviations per
coil of <3 mm and average statistical deviations below
37
WENDELSTEIN 7-X
(∆B/B0<<2x10-4 being ∆B the significant Fourier components of the magnetic field error at the plasma boundary
and B0 the average magnetic field on the plasma axis).The
optimisation of the design of such components is based on
distributing the electromagnetic loads among the support
elements with the objective of minimizing the deformations of the coil winding packages when energized and to
limit the stresses within acceptable values. The result of
this optimisation process leads to a reference design in
which:
– the CS and LS are realized by “solid connections” (bolted
or welded);
– the NS and PS are realised by “contact elements” which
must have a gap of the order of few mm (from 0.2 to 5) at
4 K and zero current. These gaps get in contact during the
magnetic field rise and allow the coil casing to slide and
tilt against each other during the last part of the current
ramp-up. The CS are connecting the CS blocks welded on
the non-planar coils and planar coils casings with the
extension elements welded on the central coil support
structure. The design is based on a bolted connection realized by a “single central rod” or a “matrix of rods” in
Inconel 718 sufficiently long (of the order of 400 mm) in
order to maintain the strain value of the rods below the
yield limit (1390 MPa at 4 K). A cross section of a typical
bolt array (3x3 or 2x3 matrix of rods) of a CS connection
is shown in figure 10.
means of specific sensors, in order to keep critical areas or
components (high stress, risk of collision) under control,
and to validate the prediction of the Finite Element codes.
The location and type of sensors will be based on structural analysis, CAD as-built geometry, outcome of mechanical tests (see above), market survey for cryo-vacuum
application, interfaces. Some preliminary activity has
been carried out in 2004, and this now has to be continued
in the next years.
Figure 9: CAD view of the torus hall (partial) layout
3.5 A critical issue: the W7-X Magnet Support Elements
During 2004 System Engineering was deeply involved in the
design and R&D activities related to the development of the
magnet support elements (see chapter 3.2). The magnet system of the W7-X with its planar and non-planar coils is supported by the central support structure (10 sectors connected
by bolts to form a pentagon) through Central Support (CS)
elements. In addition, the coils are connected one to the
other by the inter-coil structure consisting of:
– the Narrow Supports (NS) and the Lateral Supports (LS)
elements connecting adjacent non-planar coils casings in
the inner and outer torus region, respectively;
– the Planar Support (PS) elements connecting the planar
coils to the non-planar coils. The basic concept of the
W7-X mechanical structure is based on backing of planar
coils and non-planar coils against the central coil support
structure through the CS and wedging among the non-planar coils casings through the NS on the inner side and the
LS on the outer side. The CS and the inter-coil support
structure elements are critical components which have to
satisfy the following requirements:
– to operate in high vacuum (10-4 Pa) and at cryogenic temperature (4 K),
– to withstand high forces and moments,
– to allow the assembly of the machine with high accuracy
Figure 10: Cross section of a typical bolt array of a central support
connection
To validate the design of the CS bolted connection, tests on
two mock-ups are in progress. A single M30 bolt mock-up
has been preloaded up to 850 MPa using “Superbolt” tensioner. Successively, the mock-up has been cooled down to
77 K. A mock-up simulating one row with 3 rods M30 has
been manufactured and is ready to be tested at 77 K. During
the tests nominal axial force, shear load and bending
moment will be applied for 4000 cycles simulating the
experimental life of W7-X.
The basic design of a NS is shown in figure 11 and it
includes:
38
WENDELSTEIN 7-X
compressed against it with a maximum force of about
1.1 MN and at the same time is subject to sliding (up to
2 mm) and tilting (up to 0.5°) on the adjacent counter-faces.
The Al-bronze pad is coated with a MoS2 lubricant layer to
decrease the friction factor in order to avoid stick-slip effect
during sliding. Tests at room temperature have been performed at the IABG company with an ad-hoc facility applying simultaneously 1.5 MN compression load, 2 mm sliding
and 0.5° tilting. After 4000 cycles simulating 15 years of
experimental life of W7-X no stick-slip effect and no erosion of base material was observed. In addition, a friction
factor between 0.1 and 0.2 was measured. Friction tests at
vacuum condition (10-4 Pa) and cryogenic temperature
(77 K) are in progress. A schematic view of the cryo vacuum
tests on the narrow supports is shown in figure 12.
The LS are connecting adjacent non-planar coils casings in
the outer region. Considering the high loads (mainly torsion
and bending moments up to 130 and 230 MNmm respectively) and the limited space available, only welded joints
appear to be feasible. The PS are connecting planar coils
with non-planar coils casings through sliding joints. Four
planar supports for each planar coil are foreseen. The design
of the sliding joints is the same as in the case of the narrow
supports.
Figure 11: Basic Design of a Narrow Support. The sliding pad is kept in
position within the pad frame by the spring.
– the NS elements welded or cast on the non-planar coils
casings;
– a central pad made of “anti-seizing” material (Albronze). The pad with spherical surfaces can slide and tilt
with respect to the stainless-steel counter-faces;
– a spring to bring the pad in the centre position of its housing;
– a pad frame connected to one of the two adjacent NS elements to house the spring-pad system.
When the pad goes into contact with the counter-face, it is
4 Assembly
4.1 Assembly Site
A new preparation hall for plasma vessel sectors, ports, busbars and outer vessel-shells was set-up and commissioned.
Together with two smaller halls (coils, central ring) all necessary preparation space is now available. Additional external storage space was commissioned to be able to take delivered components (e.g. ports). A temporary awning was
erected in front on the main assembly area to keep the
assembly area clean and to avoid interruptions of the process
due to temperature changes. The main crane in the torus hall
was reinforced to 150 t to be able to perform assembly
processes in parallel. A detailed investment study was made
to buy a suitable machine for on-site machining of coils,
vessel parts and ports. Due to the large costs this investment
was stopped for the time being. The assembly area was completed with small parts storage, with a shift leader office, a
work centre for welders and a small assembly workshop.
These activities will be continued in 2005 to provide sufficient space for staff accommodation.
Narrow
Support
Cryo
vacuum
4.2 Assembly Equipment
Assembly tools for the handling and transportation of coils
and plasma vessel sectors were commissioned. The design
of a large, extensive and very complex lifting structure for
half-modules and modules (100 t) was completed, the manufacturing was launched. The design of mounting stand IVa
Figure 12: 3-D view of the full scale cryo vacuum tests on narrow support
mock-ups
39
WENDELSTEIN 7-X
was completed and the manufacturing started. The stand is
needed in the torus hall to assemble very precisely 100 t
magnet modules with the lower shell of the outer vessel. For
metrology a second laser tracker was bought to balance the
overloading of the existing equipment. Additionally, after
strong recommendations from members of the assembly
board and from experts of other fusion experiments a photogrammetry system for metrology was purchased. With
assistance from the sub-division SE the procurement for a
laser scanner system was worked out. The scanner system
will be operated by the metrology team. To assist the manufacturing of the bus-bars in FZJ a “Messarm” was procured
and put at the disposal of FZJ.
4.4 Trials and Trainings
Several coil threading tests were done in 2004. For this, coils
were taken from the manufacturing process used for the trials and returned to be completed. Threading of coil type 3
and 1 across the first plasma vessel sector (without thermal
insulation) confirmed the pre-calculated clearances. The
threading tools worked as planned. The threading time needed for a single coil threading was less than predicted. Also
trial assemblies of the plasma vessel sectors and the Thermal
Insulation have been performed successfully. Handling and
alignment tests with a pre-manufactured tenth of the Central
Support Structure have been completed. Minor modifications on assembly tools and devices made to simplify the
process and to facilitate the first application in the real
assembly procedure. A welding trial on plasma vessel half
modules took place in September. This trial served as a qualification of the welding process (alignment procedure, double V-weld under real assembly conditions, welding parameter, distortion, welding inspection, leak testing…). Two
pieces of the plasma vessel of the former DEMO-cryostat
have been prepared for this trial such that they correspond to
the real geometry of the W7-X sectors. It was shown, that
the shrink-accuracy of about 2 mm was within the expected
range. Additional computer aided threading simulations
together with the company DJO have been performed to
define areas on coils and plasma vessel sectors where tolerances could be relaxed. Handling training with two mobile
cranes was carried out. These cranes allowed access to difficult areas of assembly. Special attention was given to trials
with narrow support elements (NSE) and lateral support elements (LSE). Both types of elements have to be installed
between adjacent coils at the beginning of assembly.
Originally a bolted connection was foreseen to join the coils
with these elements. The recent modifications however,
which have been necessary to reinforce the mechanical
structure of W7-X, require stronger and specially customised joints. For this, a welding development program for
LSE was established together with the ZAT department in
FZJ. The aim is to attain high-strength welds with restricted
accessibility with minimal, symmetric and well predictable
shrinkage. First on-site welding trials showed good results.
In terms of NSE a high-accurate alignment method for nonplanar coils must be developed. This required some modification on both the already existing pre-assembly equipment
and the pre-assembly method. Accompanying computer
aided coil-threading studies were made to optimise the existing threading-paths. Parts of the NSE will be shrink-fitted in
already assembled coils. For this, a shrink-fit assembly
method with liquid nitrogen was successfully established.
The mechanical customising of NSE requires a special
mould procedure to define the dimensions between two
adjacent coils. For this, an additional trial assembly-step for
every coil had to be introduced again, which was foreseen
Figure 13: Threading trial of non-planar coil type 3 across the non-insulated PV sector. The coil is held and moved with the threading tool. The PV
sector is attached on its bean-shaped side to the assembly structure.
4.3 Machine Base
The basic design was completed and the call for tender
phase started. To improve the mechanical support of the
machine base to the outer vessel and to the magnet system a
re-design was necessary. Because of this, the tender phase
was stopped and will be continued in the beginning of 2005.
40
WENDELSTEIN 7-X
5 Diagnostics
originally in the very beginning of the assembly planning.
Together with the University of Rostock some mechanical
tests of assembly tools were performed.
5.1 Overview
The full set of diagnostics proposed for W7-X and assigned
to the 140 diagnostic ports has been reduced to a subset of
start-up diagnostics which comprises the diagnostics necessary for the safe operation and the control of the machine
and those diagnostics adapted to and being indispensable
during the start-up phases of the experiment. The restructuring of the W7-X project demanded this concentration. The
diagnostics department is divided into nine expert groups,
the technical coordination and the documentation and control. Temporary working groups cover certain R&D programs like the development of heat-resistant plasma facing
optical components or the development of in vessel components insensitive to large microwave stray radiation levels
due to non-absorbed ECRH.
4.5 Periphery
The planning of the water cooling circuits was continued
and refined. Most of the input data for the manufacturing
design and most of the interface conditions of the cooling
system have been fixed meanwhile. Hence, the manufacturing design of the first section in the second basement will
start in 2005. The design work for the instrumentation routing inside the cryostat was started. The instrumentation
shares its installation space with the bus-bar system and
with the helium-pipe system. A close collaboration between
the responsible designers in the periphery group, in the subdivision Basic Device and in the FZJ was organised to cope
with extreme small design clearances. First conceptual studies for the electrical equipment in the torus hall were started.
5.2 Reports of Expert Groups
The following chapters briefly summarize the main activities in the expert groups of the project. Due to assigned priorities there is as yet no activity in the subgroups on fluctuations and on neutron detectors.
4.6 Component Preparation
All necessary handling equipment and tooling for the preparation of coils and vessel sectors was designed, procured and
commissioned in time. Two sectors of the half-module have
been prepared together with MAN DWE including instrumentation and thermal insulation and cryogenic shield. Two
more sectors (out of total 20) are available for the continuation of the work. The inspection procedures for coils were
qualified. The design work of the complex coil-header support structure (every coil must get its own structure) was
started, the first structures will be manufactured in time with
the first coils.
5.2.1 Edge and Divertor Diagnostics
Mechanical tests of a full-scale prototype array of the targetintegrated pop-up Langmuir probes have been successfully
completed. The final design will start in April 2005.
Prototype electronics for power supplies and data acquisition have been designed and are being constructed.
Activities on the thermographic system concentrated on the
selection of appropriate camera types and on the design of
the optical transmission systems. Basic studies on the accuracy of surface temperature measurements in dependence of
the surface morphology of carbon have been extended to test
specimens of the CFC material foreseen for the W7-X divertor targets. For the neutral gas manometers, an immersion
system was designed which allows for retraction of the
manometers out of the vented machine and, therefore, for
maintenance, replacement, and repair. Ports for manometers
have been selected. A prototype digital electronic control
system was assembled and tested. For the coolant calorimetry, suited low-cost flow meters have been selected. The proposed system was adapted to the cooling circuit parameters.
4.7 Work Preparation, Assembly Planning and Documentation
The first sections of a detailed quality assurance and assembly plan (QAAP) were worked out and implemented with
the assistance of both quality management and experts from
industry. The QAAP comprises detailed work- and inspection-instructions, contains hold- and information points and
it documents test results, signatures, notes etc. To provide
and to document all work packages of the entire set-up of
W7-X about 450 of these QAAP sections with hundreds of
both working-instructions and inspection-instructions are
needed. A work safety system which is basing on an industrial manual for plant engineering and construction was
worked out and aligned with the internal IPP rules. The safety system also controls the accessibility permission to the
assembly area. The safety instructions were combined in an
Assembly Safety Manual.
5.2.2 Microwave Diagnostics
Start-up microwave diagnostics are a multi-channel interferometer with an additional channel in the plane of the bulk
plasma Thomson scattering system and the multi-channel
ECE radiometer. Indispensable preparatory work for the
later reflectometry system is conducted as well. Assembly
plans of these systems have been completed. The lasers and
all sensitive electronics and RF components will be located
41
WENDELSTEIN 7-X
in the peripheral diagnostic region outside the torus hall.
Optical and quasi-optical transmission lines to the experiment and the corresponding breakthroughs through the
walls of the torus hall have been designed. The optics set-up
of the interferometer as well as the laser beam parameters
was optimized to minimize interferometer sensitivity against
mechanical vibrations and thermal drifts during long-pulse
operation. The set of eight sightlines foreseen for a later
development step and optimized to gain maximum information on the density profile is being modified to cope with the
technical constraints set by the vacuum window ports and
the retro-reflectors incorporated in the first wall which must
also provide cooling of these mirrors. Laboratory tests with
a single-channel interferometer continued. In the frame of a
temporary working group a big microwave stray radiation
test chamber has been set into operation and has been characterized. It will allow for the development of windows, vacuum sealings and many other components of the vacuum
vessel which must withstand non-absorbed ECRH radiation
at high power flux density levels.
5.2.5 Thomson Scattering
Work concentrated on the observation system for the scattered light. The movement of the observation ports has been
analysed in detail. To overcome the aperture restrictions
caused by this movement, an immersion tube has been conceptually designed applicable to all optical diagnostics. The
mechanical support structure inside the torus hall for the
laser beam entrance and the observation optics has been
designed. It makes use of the platform to be erected in the
torus centre during machine assembly. A joint development
of advanced polychromators has been started with the
Thomson scattering group of ASDEX Upgrade.
5.2.6 Soft X-Ray and Magnetic Diagnostics
The first eight saddle coils of the magnetic diagnostic have
been installed on the first module of the W7-X plasma vessel. The actual geometric position of the cable forming the
coils has been measured by means of a laser tracker system.
The resulting lateral deviation between designed and measured position is less than the required value of 3 mm. The
design of the coil systems being placed between plasma vessel and thermal insulation, the Rogowski and saddle coils,
has been presented in one of the design reviews. The concept of building pseudo-Rogowski coils by inner and corresponding outer coil segments allows to determine parasitic
currents flowing in the plasma vessel, which is toroidally
conducting. Major progress has been made in the electronic
integrator development. A digital variant has demonstrated
low drifts (70 µVs/1000 s) allowing to measure the plasma
current with a systematic error lower than 50 A after 30 minutes of integration time.
5.2.3 Charge Exchange Diagnostics
The group develops the diagnostic beam needed for CXRS
measurements and, beyond the start-up phase of W7-X, for
ion energy distribution function measurements with a set of
neutral particle analyzers. The injector is being developed in
collaboration with FZJ and the Budker-Institute, Novosibirsk. The high voltage power supply is being fabricated.
Laboratory tests of various ion sources are being conducted.
5.2.4 Spectroscopy
The high-efficiency XUV overview spectrometer (HEXOS)
for observation of prominent impurity lines has finished its
design phase and is being manufactured by Jobin-Yvon,
France. Preparatory work for the future laser induced fluorescence diagnostic and the optical paths for the laser beam
from the diagnostic hall to the W7-X entrance ports have
been designed and the necessary space has been allocated.
Tests of different bolometer detector types, gold foil and
photo diode array based, were prepared on the WEGA and
Vineta experiments. The movements of the diagnostic ports
for various W7-X operating conditions have been analysed
and their impact on the design of the re-entrant view ports of
the spectroscopic diagnostics has been investigated. In the
frame of a temporary working group a series of fatigue tests
on a prototype water cooled quartz window were successfully completed. The window remained fully high vacuum
compatible over 70 heat cycles with peak window temperatures of 500 °C. The observed absolute window temperatures as well as the radial temperature profiles agreed with
corresponding ANSYS thermo-stress predictions.
5.2.7 Heavy Ion Beam Probe and Fast Particle Diagnostics
The 2 MeV accelerator on loan from the Text-U experiment
in Austin, Texas, which is foreseen as an energetic thallium
ion source in a heavy ion beam probe diagnostic has been
installed. The approval process by the German authorities is
being conducted successfully. Beam trajectory calculations
have been carried out to determine the compatibility with invessel divertor components and the spatial resolution
expected. The calculations demonstrated the promising
diagnostic opportunities in the K11-N11 assigned port
geometry.
5.3 Collaborations
The diagnostics are being developed in close collaboration
with FZJ. Agreements on collaboration covering particular
subjects were made with the Budker Institute, Novosibirsk, the
PTB-Braunschweig, IFP-CNR Milano, the Kharkov-Institute
of Physics and Technology, and the University of Helsinki.
Other European institutions from Denmark, Hungary, Spain,
Sweden, Portugal, and Poland expressed their interest to collaborate. Closer contacts are being established.
42
WENDELSTEIN 7-X
6 Heating
guidance of CPI-experts. The tube was installed in a further
gyrotron socket at the IPP (see figure 14). The present working parameters are 500 kW/200 s, 700kW/40 s. The power is
now being pushed towards 800 kW in a daily conditioning
operation. The preparations for the next gyrotron installation
are going on.
6.1 Electron Cyclotron Resonance Heating
The Electron Cyclotron Resonance Heating (ECRH) system
is being developed and built by FZ Karlsruhe (FZK) as a
joint project with IPP and IPF Stuttgart. The “Projekt
Mikrowellenheizung für W7-X” (PMW) co-ordinates all
engineering and scientific activities in the collaborating laboratories and in industry. It is responsible for the realisation
and installation of the ECRH system for W7-X. The whole
system is designed to provide the W7-X experiment with a
microwave power of 10 MW at a frequency of 140 GHz for
30 minutes. It will consist of ten gyrotrons with 1 MW
power each, a low loss continuous wave (CW) capable transmission line and flexible in-vessel launch antennas, which
are also designed for a continuous wave full power operation
in a microwave and plasma environment.
6.1.1 Gyrotron Development and Installation
The development of the gyrotron within the framework of an
European R&D program (FZK, CRPP Lausanne, TED
Thales Electron Devices, IPF Stuttgart and IPP Greifswald/Garching) has been successfully finished. Two prototype tubes were manufactured within this program. The first
pre-prototype gyrotron “Maquette” was already installed in
Greifswald and operates routinely for high power test of the
W7-X transmission line elements, as well as for high power,
long-pulse tests of an ITER remote-steering launcher mockup within the frame of an EFDA contract. The second R&Dprototype gyrotron incorporates some improvements compared to the Maquette and delivered the following
long-pulse parameters: 0.9 MW for 3 min, 0.54 MW for
almost 16 min and 0.26 MW for nearly 22 min. The efficiency of RF generation is between 40 and 50 %. Outgasing of the internal ion getter pumps due to RF heating
prevents longer pulses. An improved electron gun with better azimuthal homogeneity of electron emission was implemented at TED, the gyrotron is presently under retest at FZK
in the first (out of eight) series magnets from Cryomagnetics
Inc. to qualify the magnet and verify the improvements. First
short-pulse tests showed the expected performance of both
the magnet and the gyrotron (1.1 MW with 50 % efficiency
employing the single-stage depressed collector). PMW has
ordered 7 series gyrotrons from TED. The delivery of the
first tube (now with external, shielded ion getter pumps) is
somewhat delayed and is scheduled for February 2005,
which has, however, no influence on the delivery schedule
of the remaining 6 tubes. Tests at FZK towards full performance within the test stand limitations (3 min) will follow, the
required processing and testing time is estimated to be about
4 months. Besides the 9 TED gyrotrons, IPP had ordered a
140 GHz gyrotron with the same specifications at the U.S.
company CPI. This tube is presently being processed under
Figure 14: Installation of the CPI gyrotron in box Echo 5 at IPP-Greifswald
6.1.2 ECRH Periphery
All peripheral systems for two gyrotrons are operational in
Greifswald. Two modules (65 kV, 50 A each) of the central
HV supply are routinely operated. Two more power supply
modules have successfully passed the site acceptance test at
IPP and are available for the next gyrotrons. The first (out of
ten) HV-Modulator/Crowbar units, which were developed at
IPF Stuttgart, was delivered to IPP early 2004 and runs in
routine operation together with the CPI-gyrotron. Series
production has started and the second system is presently
under test at IPF, delivery is scheduled for mid February
2005. The remote control system is continuously improved.
In contrast to the provisional state of the “Maquette” installation, the CPI-gyrotron installation is completely remote
controlled by a SIMATIC system. All gyrotron parameter
are visualized on a WinCC graphical user interface. A prototype of the new fast interlock system was implemented.
43
WENDELSTEIN 7-X
ation test chamber (see chapter 5.2.2) was brought successfully into operation in November 2004 at IPP Garching.
Here an old W7-AS gyrotron was used to generate up to 25
kW ECRH power for several minutes. The chamber was
equipped with microwave and thermo-graphic diagnostics.
The measurements have confirmed the antenna design for
the generation of an isotropic and homogenous microwave
radiation inside the chamber. The chamber is ready for the
ECRH-launcher mock-up test.
6.1.3 Transmission Line
The transmission line is an optical system, which operates at
normal pressure. It consists of single-beam wave-guide
(SBWG) mirror modules mounted on a common base frame
and multi-beam wave-guide (MBWG) mirrors for long-distance transmission. The integrated design of the individual
components of the microwave transmission system is in
steady progress at IPF Stuttgart. The installation of all
SBWG-mirror modules as well as the MBWG-mirrors is
completed in the beam duct. Two beam lines are equipped
with the full set of diagnostics and are tested with increasing
power loading. So far the open mirror concept has proven its
unique flexibility and easy handling. The construction of the
”ECRH-towers” had started. This installation inside the
experimental hall will incorporate the remaining mirrors for
the beam transmission into the ECRH ports. We have envisaged a modular design, which allows a fast assembly of the
completely equipped tower modules inside the experimental
hall, as soon as the installation space will be available.
6.2 Ion Cyclotron Resonance Heating
With the restructuring of the project W7-X the design and
development of the ICRH system was postponed until the
end of 2005. Thus three professionals (one physicist, one RF
engineer, one mechanical engineer) became available almost
fulltime for the project. Less than 5 % of their time is still
devoted to the ICRH system. An overview of the planned
system was presented to most of the European and some
American experts on ICRH as part of a Ringberg workshop.
Additional experiments were done on the testbed in
Garching to develop cw capable transmission lines. There it
was shown that cooling of the outer conductor is sufficient
for matched transmission lines even at ITER parameters.
6.1.4 In-Vessel ECRH Components
The design of the in-vessel components has been continued
in close cooperation with the relevant divisions of W7-X.
The layout parameters for the design were chosen such, that
the front structure will withstand a plasma radiation of
100 kW/m2. In addition we expect a strong microwave stray
radiation inside the port with the consequence that even
there every component has to be cooled. The design of the
front-steering launcher (see figure 15) was finished and the
fabrication of a simplified mock-up launcher at FZK has
started. This mock-up will be tested in a special vacuum
6.3 Neutral Beam Injection
Neutral beam heating is foreseen in W7-X for bulk heating
of the plasma, necessary in particular for the high-beta
regime at elevated densities. A total power of up to 14/20
MW with 55 keV hydrogen/100 keV deuterium beams has
been approved and will be built up in two stages: 5 MW first
in stage I, additional 15 MW later in stage II. In 2004
progress of NBI for W7-X was further slowed down to
essentially keep-in-touch, because of the transfer of the NBI
staff to W7-X. The situation will remain unchanged for at
least one more year.
Figure 15: Antenna design for 3 ECRH beams with motor-driven biaxial
movable mirrors
chamber under realistic stray-radiation loading to verify the
mechanical and cooling concept. The fabrication of the W7X diamond disc torus windows is running within the time
schedule, six windows are already delivered. The stray radi44
WENDELSTEIN 7-X
Scientific and Technical Staff
IPP Garching
Experimental Plasma Physics I (E1): B. Streibl, C. Li,
S. Schweizer
Materials Research (MF): H. Bolt, J. Boscary, H. Greuner
Technology (TE): F. Braun, B. Heinemann, E. Speth,
P. McNeely
Computer Center Garching (RZG): P. Heimann, J. Maier,
M. Zilker
Central Technical Services (ZTE) Garching: B. Brucker,
R. Holzthüm, R. Semler, H. Tittes, M. Weissgerber
Technical Services (TD) Greifswald: M. Braun,
G. Pfeiffer, M. Winkler
Wendelstein 7-X Subdivisions
Project Coordination
Head: Dr. Hans-Stephan Bosch
A. Berg, H.-J. Bramow, R. Brakel, J. Dedic, W. Fay,
J.-H. Feist, G. Gliege, M. Gottschewsky, K.-H. Hanausch,
U. Kamionka, B. Kursinski, T. Kluck, J. Knauer, A. Lorenz,
J. Maier, D. Naujoks, T. Richert, M. Schröder, R. Vilbrandt,
D. Williams, U. Wenzel
Basic Device
Cooperating Research Institutions
Forschungszentrum
Jülich
(FZJ):
W.
Behr,
G. Bertschinger, W. Biel, G. Czymek, B. Giesen, D. Harting,
H. Jägers, M. Lennartz, P. Mertens, O. Neubauer, A. Panin,
A. Pospieszczyk, U. Reisgen, D. Reiter, J. Remmel,
M. Sauer, W. Schalt, G. Schröder, J. Schruff, B. Schweer,
J. Wolters
Forschungszentrum Karlsruhe (FZK): A. Arnold,
G. Dammertz, I. Danilov, R. Heidinger, H. Hunger, S. Illy,
K. Koppenburg, W. Leonhardt, D. Mellein, G. Neffe,
B. Piosczyk, O. Prinz, M. Schmid, T. Rzesnicki, M. Thumm,
R. Vincon, X. Yang
Stuttgart University (IPF): H. Babilon, P. Brand,
G. Gantenbein, E. Holzhauer, W. Kasparek, H. Kumric,
O. Mangold, G. Müller, B. Plaum, K.-H. Schlüter,
K. Schwörer
Rostock University, Germany
University of Applied Sciences Neubrandenburg,
Germany
Atomic Institute of the Austrian Universities, Vienna,
University of Technology: H. Fillunger, R. K. Maix
Commissariat à L’Énergie Atomique (CEA), Saclay,
France: M. Jacquemet, L. Genini, T. Schild
ENEA Centro Ricerche Energia, Frascati, Italy
CNR Istituto di Fisica del Plasma, Milano, Italy
CRPP EPFL, Switzerland
Warshaw University, Warshaw, Poland
Efremov Institute, St. Petersburg, Russia
Institute for Nuclear Research, Kiev, Ukraine:
V. V. Lutsenko, Y. I. Kolesnichenko, Y. V. Yakovenko
Kharkov Institute of Physics and Technology, Kharkov,
Ukraine: L. Krupnik, A. Melnikov, D. Perfilov
Head: Dr. Manfred Wanner
J. Ahmels, J. Baldzuhn, H. Bau, D. Birus, A. Cardella*,
C. Dhard, H. Dutz, H. Ehmler, F. Füllenbach,
W. Gardebrecht, H. Grote, D. Gustke, B. Hein, K. Hertel,
A. Hölting, R. Kairys, B. Missal, T. Mönnich, M. Nagel,
B. Petersen-Zarling, M. Pietsch, D. Pilopp, D. Rademann,
J. Reich, K. Riße, P. Rong, T. Rummel, N. Rust,
C. Sborchia*, F. Schauer, R. Schröder, H. Viebke,
O. Volzke, W. Schneider
System Engineering
Head: Dr. Maurizio Gasparotto
T. Andreeva, S. Bäumel, T. Broszat, V. Bykov, A. Capriccioli,
C. Damiani, W. Dänner, A. Dübner, A. Dudek, H. Greve,
E. Harmeyer, F. Herold, N. Jaksic, J. Kißlinger, Y. Krasikov,
J. Lingertat, M. Rumyantsev, N. Rüter, A. Schewalenko,
H. Schmidt, W. Schulz, A. Schütz, K.-U. Seidler, J. SimonWeidner, M. Sochor, L. Sonnerup, F. Starke, M. Steffen,
J. Tretter, A. Vorköper, S. Wendorf, K. Zimmermann
Assembly
Head: Dr. Lutz Wegener
A. Benndorf, T. Bräuer, M. Czerwinski, T. Eich, M. Endler,
S. Gojdka, D. Hartmann, D. Holtum, F. Hurd*,
A. John, R. Krampitz, F. Kunkel, H. Lentz, E. Lorenz,
H. Modrow, J. Müller, U. Neumann, H. Rapp, L. Reinke,
K. Rummel, D. Schinkel, U. Schultz, E. Schwarzkopf,
H. Schwarz, C. von Sehren
Physics
Head: Prof. Thomas Klinger
T. Blum, H. Braune, R. Burhenn, V. Erckmann, P Grigull,
H.-J. Hartfuss, C. Hennig, U. Herbst, D. Hildebrandt,
M. Hirsch, F. Hollmann, R. König, P. Kornejev, G. Kühner,
H. Laqua, H. Laqua, M. Laux, G. Michel, S. Mohr,
I. Müller, K. Näckel, U. Neuner, H. Niedermeyer, F. Noke,
E. Pasch, S. Pingel, F. Purps, J. Saffert, J. Schacht,
A. Spring, A. Stareprawo, H. Thomsen, S. Valet, A. Weller,
A. Werner, M. Ye, D. Zhang
*seconded from CEU
45
WENDELSTEIN 7-X Applied Theory
Head: Dr. Henning Maaßberg
1 International Energy Confinement Scaling
The group concentrated of the physics modelling and integrated data evaluation for W7-X.
This includes work on neoclassical transport,
development of a predictive stellarator transport code, fast equilibrium recovery by function parametrization, edge physics simulations
and modeling of NBI and ECRH heating. Apart
from that W7-AS data in connection with
detachment in divertor experiments, ECCD and
high-beta were analyzed.
Within a comprehensive international collaboration a revision of the ISS95 confinement
data base was continued (NIFS,
CIEMAT, U-Kyoto, ANU, UWisconsin, U-Stuttgart, and
IPP). An update resulting in
ISS04 was proposed. Robustness of scaling results was investigated. As an outcome, a joint scaling appears to be
compatible with previous results only, if grouping of the
data was allowed. The, however, major trends can be comprehended. First studies of configuration dependent magnetic field structure parameters, such as the effective helical
ripple (applicable for the long-mean-free path regime) and a
plateau factor were performed, but a clear correlation could
not be revealed.
The bootstrap coefficient asymptote for an axisymmetric
configuration at extremely low
collisionalities calculated by
DKES (with much less convergence problems) was compared
with the analytic result for large
aspect ratio: excellent agreement was obtained.
4 Neoclassical Transport:
Tokamak Fits
For a database of tokamak configurations in an extended
“standard model” (different ι, r/R and elongation) the
3 mono-energetic transport coefficients (radial transport,
bootstrap current and electric conductivity) were calculated
using DKES for all collisionalities. Based on the flux-friction relations (due to symmetry) only the bootstrap current
coefficient is fitted (and the other Pfirsch-Schlüter contributions) for a good and consistent representation of all coefficients (EURATOM collaboration with TU-Graz).
2 International Collaboration on Development of Predictive
and Analysis Transport Code
5 Function Parameterization for Wendelstein 7-X
In reported period we continue development of predictive
and analysis transport code for stellarators. The preliminary
agreement with Princeton Plasma Physics Laboratory and
Oak Ridge National Laboratory on the collaborative development of a transport code was concluded. The high priority
tasks were defined. IPP takes main responsibility for the
development of modules for the solution of the diffusion
equations; neoclassical transport (including impurity transport), ECRH/ECCD, NBI/NBCD, and for the modeling of
the current feed-forward control. PPPL and ORNL will concentrate their efforts on the development of the modules for
magnetic equilibrium reconstruction, momentum correction
in the neoclassical transport modeling, and the feedback
control. Both sides take part on design interfaces between
different modules including the multi-language interface.
The work to provide a fast real to magnetic space coordinate
transformation based on the method of Function
Parametrization (FP) has been carried on. The work on the
vacuum magnetic configurations which have been considered in the starting phase has been finished. A mixed quadratic, a mixed-cubic polynomial model and an artificial neural network have been tested for axis parameters like axis
position in the main planes, central rotational transform and
magnetic field strength on axis in the main planes.
Additionally, the parameters of the natural island of the
main low order rationals, i.e. radial location and width, were
modeled alike. In all cases the cubic model was found to
perform best. In a next step the profiles of the rotational
transform and of the differential volume were modeled with
an FP-model where the radial dependence was given by a
quadratic polynomial in squares of the effective radius (r2eff),
each polynomial coefficient being a mixed cubic FP-model
in the coil current ratios. In the same way, the Fourier coefficients (derived from the field line tracing code W7) were
modeled to give access to the flux surface structures. The
quality of this model is not fully satisfactory with respect to
spatial accuracy. However, it is well suited to provide initial
guesses for the free-boundary calculations with the VMECcode to develop the finite <β> FP covering the same configurational space as defined for the vacuum configurations
(EURATOM collaboration with UCC).
3 International Collaboration on Neoclassical Transport
Benchmarking of the bootstrap-current coefficient was initiated using the Drift Kinetic Equation Solver (DKES) and a
δf Monte Carlo code to calculate the neoclassical transport
coefficients in the standard configurations of W7-X and
LHD. Good agreement was obtained up to moderate collisionalities (plateau-regime) but the δf MC scheme strongly
deviates at low collision frequency (even though the cost
becomes prohibitive for these calculations). Future developments will therefore concentrate on an improved physical
ansatz for the lowest-order distribution function appearing
in the δf “marker” equation so as to accelerate convergence.
47
WENDELSTEIN 7-X Applied Theory
6 Magnetic Configuration Database
A database for magnetic equilibria of Wendelstein 7-X was
designed. The design assures compatibility with future
experimental databases and is linked to machine settings,
e.g., coil parameters. Beyond storage administration, parameters describing flux surface properties and derived quantities were included for database access employing physical
criteria. In addition, an Application Programming Interface
(API) was designed for all database operations from highlevel programming language codes. Testing and transfer of
data into the database is foreseen in 2005 (cooperation with
W7-X Physics and XDV).The development of the programs
for the transform from real space to magnetic coordinates
and for the visualization was finished. The documentation
for these tools with FORTRAN and C++ examples was written. These programs provide very flexible and fast tools for
all mapping applications.
7 NBI Current Drive Simulation for Wendelstein 7-X
A new Fokker-Planck/Monte-Carlo hybrid technique was
developed and applied for the NBI power deposition in
W7-X. In this technique, the slowing-down of the fast NBI
ions on flux-surfaces (without radial diffusion) is calculated
with a fast FP solver, and this solution is used in the δf MC
technique for the marker equation. Since the radial diffusion
time scale is much shorter than the slowing-down time, a
significant speed-up of the estimation of the power deposition profiles was obtained by this hybrid technique (collaboration with V. Tribaldos, CIEMAT and S. Murakami,
NIFS).Neutral beam current drive (NBCD) scenarios in
W7-X were analyzed in detail. First of all, the power deposition profiles as well as the NBCD profiles are nearly identical for co- and counter-injection reflecting the W7-X optimization (drift-surfaces close to flux-surfaces). In general,
the bootstrap current could be compensated by counterNBCD, however, the rotational transform profile is significantly affected; see section 9, figure 2b.
Figure 1: Time evolution of the loop voltage and total toroidal current
9 Predictive Modeling of bootstrap current compensation
According to the W7-X priorities in the development of the
predictive transport code (see section 2), the bootstrap current was calculated. All mono-energetic transport coefficients were computed by the DKES code for the W7-X
“standard” configuration for which a strongly reduced bootstrap current was obtained (part of the W7-X optimization
criteria). A rather conservative estimate of the tolerable plasma current is obtained from the shift of the island structure
close to the targets with a strong effect on the position of the
recycling zones. Following this estimate, the plasma current
should be controlled within a range of about 10 kA. The
bootstrap current even for the “standard” configuration can
easily exceed this value. Consequently, first scenarios of
current control by using electron cyclotron current drive
(ECCD) and neutral beam current drive (NBCD) were analyzed (no transformer in W7-X). In the ECCD simulation,
8 Beam-/Ray-tracing Code for ECRH
The new beam/ray-tracing code (BRT-code) calculates both the
power deposition and the driven current profile, and includes
also the tools to analyze the ECE spectrum (i.e. the Te-profile
with its spatial resolution for the low-field-side observation). At
present, the draft version of the code is tested.The absorption
and emission coefficients are defined through a general (nonMaxwellian) distribution function which might be estimated
from Fokker-Planck simulations with the quasi-linear formulation of the ECRH, i.e. quasi-linear degradation effects of the
absorption can be included. For the estimation of the linear
ECCD efficiency, the adjoint approach is used.
48
WENDELSTEIN 7-X Applied Theory
much longer than this skin-time – the total toroidal current
reaches steady state after 100 seconds with the L/R time of
20 seconds.
The modeling showed also that strong localization of ECCD
leads to strong perturbation of iota profiles (figure 2a).
Moreover on-axis counter ECCD decreases the rotational
transform in the central region of plasma down to zero (see
also section 13 for W7-AS). NBCD has broader profile, see
figure 2b. The NBCD profiles were estimated using
δf-Monte Carlo modeling, see section 7. In order to avoid
long relaxation times we proposed the following scheme for
Feed-forward or Predictive control:
– calculate the bootstrap current distribution using measured
plasma parameters in the “online” transport analysis
– determine and apply ECCD needed.
The first results of modeling of the Feed-forward control
showed that it is possible to keep the residual totoidal current in a tolerable range. The study of the Feed-forward control will be continued with the self-consistent calculation of
heating and current drive included.
10 Physics of detachment in Wendelstein 7-AS
Dedicated 3D EMC3-EIRENE simulation results show poor
neutral screening efficiencies for the divertor radiation case,
i.e. for small plasma-to-target distances ∆x or large connection lengths Lc in the ranges consistent with the experimentally observed unstable detachment. This link between poor
neutral screening and unstable detachment has been investigated by a linear stability analysis using the 3D simulation
results. This study identifies an instability driven by the
recycling neutrals penetrating into the core as being responsible for the observed unstable detachment [Y. Feng et al.,
2004 Contrib. to Plasma Phys. 44 1-3 57]. The growth rate
of this instability is proportional to the variation of the neutral penetration flux into the core with the SOL power,
|∂Γrc/∂Psol|, which is much larger for the divertor radiation
than for the inboard-side radiation. That is, in the divertor
radiation case the neutral screening efficiency is too low to
limit the growth of the recycling flux entering the core.
Decreasing the edge density has a stabilizing effect, in
agreement with the experiments.
Figure 2: Current free (Ο) iota, c) iota (∇) with bootstrap current, final (∆)
iota after 100 sec with compensating current drive: a) 15 kA of counter
ECCD; b) 26 kA of counter NBCD
8 MW heating with slightly off-axis deposition and a fixed
density profile (n<0.8 1020 m-3) were assumed. The temperatures as well as the ambipolar radial electric field, the neoclassical fluxes, the bootstrap current density and the parallel electric conductivity were calculated self-consistently. In
the example shown in figure 1 with Te~6 keV, Ti~2 keV at
stationary conditions, the counter-ECCD assumed with
15 kA (switched-on later) is not sufficient to compensate the
bootstrap current of 22 kA. This ECCD scenario was chosen
since- we want to isolate and study the transient processes of
a current evolution; – there is no direct coupling of the current diffusion equation with the transport, so far; – W7-X
will be equipped with steerable mirrors, which will allow to
change the ECRH launching angle for current control.
The loop voltage induced by ECCD leads to a redistribution
of the current density with the diffusive skin-time of about
2 seconds. The L/R relaxation time of the total current is
11 EMC3-EIRENE Modelling for Wendelstein 7-X
Self-consistent 3D plasma and neutral gas transport simulations for W7-X with realistic divertor plates and baffles have
been obtained for three typical island-divertor configurations. The plasma parameter distributions in the divertor
region and the particle and energy depositions on the divertor plates are shown to strongly depend on the position and
size of the islands. Configurations with strike-point positions closer to the gap of the divertor chamber generally
49
WENDELSTEIN 7-X Applied Theory
center motion is basically given by the ∇B-drift which is
finally confined in the regions with larger ι-values where
again gradients can be sustained. In this respect, the confinement physics is similar to that in tokamak discharges
with a current hole.
favour the pumping efficiency. The ratio of pumping to recycling fluxes is found to be roughly independent of the separatrix density over the low-density operational range covered
by this study and is thus a figure of merit for the quality of
the configuration in terms of density control. Lower limits
for the separatrix density, which determine the particle
exhaust capabilities in stationary conditions, are compared
for the three configurations.
14 Integrated Data Analysis
Efforts on Integrated Data Analysis were continued. Special
emphasis was led on the coupling of data analysis to modeling codes. As a proof of principle study, the joint probability
distribution of diagnostic profile data, the mapping on magnetic surfaces and transport analysis results was investigated. The technical solution of the optimization procedures
employing differently implemented codes makes use of network protocols developed for distributed computations
(namely Web Services, GRID). The development and exploration of statistical models was continued (Cooperation with
Data Analysis Group, OP).
12 ECRH/ECCD
High power ECCD experiments at W7-AS were analyzed
and compared with predictions from linear theory (adjoint
approach) as well as with non-linear (bounce-averaged)
Fokker-Planck simulations. Only at low densities, both
approaches overestimate the ECCD efficiency compared to
the current balance of bootstrap and inductive current. The
simple loss-cone modeling of the “convective” energy flux
used for the W7-AS scenarios in the Fokker-Planck simulations cannot be applied to the W7-X configurations.
Alternatively, a Fokker-Planck/Monte-Carlo hybrid scheme
is formulated for ECRH and ECCD where the heating in
form of the quasi-linear diffusion term is described by the
Fokker-Planck and the energy flux by the δf Monte Carlo
technique.
15 Diagnostics Design
Studies of the design of diagnostic set-ups within a Bayesian
framework were started. The purpose of the study is to find
an optimum set of design parameters for a range of data
given and to investigate robustness of the design parameter
set. The example chosen is the continuation of sightline optimization studies (performed within W7-X Diagnostics) for
the Wendelstein 7-X interferometer system aiming at a combination with profile diagnostics (e.g. Thomson scattering)
(Cooperation with W7-X Physics and Data Analysis Group,
OP).
13 Equilibrium Calculations for Wendelstein 7-AS
with Co- and Counter-ECCD
On-axis co- and counter-ECCD experiments in W7-AS led
to rather large positive or negative central current densities
leading to extreme deformations of the usually flat profile of
the rotational transform ι(r). In order to understand and
interpret the findings in these experiments - strong low-m
mode activity for co-ECCD and strongly degraded central
confinement visible in flat Te-profiles for counter-ECCD high resolution equilibrium calculations with the new
VMEC-version were carried out. Concerning the co-ECCD
cases, the equilibrium calculations were standard. However,
a following ∆’-analysis was not able to uniquely confirm the
tearing-mode character of the observed modes and the subject needs further investigation. The counter-ECCD cases, in
which according to estimations ι would change sign around
the locations where the Te-profiles flatten, required a separate treatment in which not the current profile was specified
but the Γ-profile. With the requirement that ι(r) has very low
values in the range of the flat temperature profile, equilibria
could be calculated which reproduced the current density
distributions predicted from theory. The flattening of the
temperature as well as the required broader ECCD-deposition profiles can be explained by the strong deviations of the
electron guiding center motions in the presence of ι-values
lower than 0.01. In such a central region the electron guiding
16 Stellarator System Studies
A power supply system for feeding the superconducting
coils of the Helias reactor has been investigated. This multiconverter supply system has been optimized, in view of low
losses in the components and minimal negative impact to the
power grid. A significant improvement of the power factor
and thereby reduction of the power factor was found.
Scientific Staff
Theory Group: H. Maaßberg (Head), A. Dinklage,
Y. Feng, J. Geiger, N. Marushchenko, F. Sardei, D. Sharma,
M. Schmidt, J. Svensson, Y. Turkin
System Studies Group: Y. Igitkhanov, C. D. Beidler
50
WENDELSTEIN 7-AS
Head: Dr. Rolf Jaenicke
Experimental Results
After the shutdown of the experiments on
WENDELSTEIN 7-AS in 2002 vacuum magnetic flux surfaces measurements have been
repeated after the initial measurements in 1988.
The new measurements have been extended to
high magnetic field strengths and to the standard divertor configuration. Nnew methods
also intended for W7-X to make magnetic field
lines visible and to measure the absolute field
strength have been successfully applied.
flux surfaces determine a geometric reference system. The
comparison demonstrates that
no changes can be detected. This
means that the shape of the MF
coils remained essentially unchanged for about 30,000 magnetic field pulses at full magnetic field of 2.5 T although
local deformations of the coils
of up to 4 mm have been measured. Also for the size of natural or symmetry breaking islands no evident changes could
be found.
Prior to the last but one campaign before final shutdown of
W7-AS control coils were installed. They were an important
tool to modify the size of the natural 5/9 islands during the
island divertor experiments. Therefore, the standard divertor
magnetic field configuration was mapped additionally. The
result is presented in figure 2 together with a numerical prediction in figure 3 obtained from the magnetic field line
tracing code W7 by A. Werner.
Flux Surfaces Measurements
The new measurements have
been carried out applying the
same electron beam technique
as in the original measurements
(see AR 1988) with a directed
electron beam and a still existing fluorescent rod at the same
toroidal position with almost
triangular surface cross section.
To make the interaction points with the field lines visible the
rod was swept across the flux surfaces within 20 s. For observation a sensitive, high resolution CCD camera was used,
allowing integration times of more than 20 s. The new measurements were restricted to a few “typical” magnetic field
configurations which are sensitive to changes in rotational
transform ι or island size. An example is presented in figure
1, where a superposition of the earlier and the new measurements is shown for the standard magnetic field configuration (all modular field (MF) coils in series only).
Figure 2: Experimentally determined flux surfaces of the standard divertor
configuration with well defined island fans.
The high current power supply used for the plasma experiments had to be utilised for the new flux surface measurements although they cannot produce the desired dc current.
However, the ripple was sufficiently small so that the measurements were only slightly perturbed. On the other hand,
this power supply allowed to extend the measurements in the
case of the standard configuration up to the full toroidal
field of 2.5 T. The increase in the coil temperature limited
the flat top pulse length to 6 s. This was just sufficient to
deduce the change of the rotational transform with increasing magnetic field from measurements similar to the ones
shown in figure 1. Since the magnetic forces try to make the
nonplanar MF coils more planar iota decreases as expected.
Figure 1: Superposition of an earlier flux surface measurement (darker)
and a new one (lighter, cross section restricted). The figures label the transit number of the electron beam. The small gap between transit 2, 7, 12, …
indicates that iota is just below 0.4.
The rotational transform in this case is just below 0.4 so that
small changes in iota can easily be seen. The earlier measurements were performed without limiters, while for the
new ones the poloidal cross section was considerably reduced by the divertor modules. Four LEDs outside of the
51
WENDELSTEIN 7-AS
currents and the B0 “necessary” for the interpretation of
diagnostic signals in which an electron cyclotron resonance
was involved (for example the ECE temperature measurements). Therefore, it was desired to calibrate the calculation
of B0 independently. An appropriate method that allows to
measure very sensitively and direction independent the
absolute value of B0, is the nuclear magnetic resonance
(NMR) technique. For the measurements a NMR sensor
with a maximum detectable field strength of 1.05 T was
used. The investigations on W7-AS were performed in the
same triangular plane in which the fluorescent rod was
installed. Furthermore, at this toroidal position the magnetic
field strength B0 is almost constant around the magnetic axis
in the standard configuration; hence position errors and
field gradients are negligible. It was found that the measured
value of B0 was about 0.5 % smaller than the calculated one.
Fluctuations in the values measured by the sensor and probably caused by current ripple and interference were of the
order of ±0.2 mT and thus negligible compared with the
desired accuracy.
Figure 3: Calculated flux surfaces of the standard divertor configuration.
Visualisation of Magnetic Field Lines
Usually the equipment used for the flux surface measurements needs to be removed during plasma experiments. On
the other hand information on the position of the magnetic
axis at various toroidal positions is frequently required for
the interpretation of diagnostic signals. This information can
be obtained rather easily if a magnetic field line close to the
magnetic axis can be made “visible”. In this case it is sufficient to position an electron gun onto the magnetic axis. The
electron beam following a magnetic field line becomes visible if the vacuum vessel is filled with hydrogen (argon or
helium) at a pressure of the order of about 10-4 mbar.
Optimal operation parameters have been determined on
WEGA (see section WEGA in this report). By using the
same sensitive CCD camera as for the flux surface measurements and an integration time of 10 s the optimum gas pressure was about 3x10-5 mbar. Again the standard configuration was chosen with rather low and high B 0. As shown in
figure 4 and on the cover page of this report up to 35
toroidal turns could be detected, corresponding to a visible
field line length of about 450 m. The increasing spread
between successive transits at higher B0 indicates the
decreasing iota as discussed in the first section (compare
also to figure 1). After the successful tests on WEGA and
W7-AS this technique is intended to be used on W7-X to
determine the position of the magnetic axis and perhaps Oand X-points of magnetic islands between plasma experiments.
The observed decrease in rotational transform from
ι/2π(reff=15.3cm)=0.3974 for B0=0.48 T to 0.3894 for
B0=2.42 T, which is about 2 %, is almost proportional to the
toroidal field B0 and not to B02 as holds for the magnetic
forces. This reflects, probably, the complicated mechanical
boundary conditions which control the transition of the
magnetic forces into the support structure. On the other
hand, the decrease of iota is fairly small so that there is no
need to modify the interpretation of the plasma experiments.
The flux surface measurements at 2.5 T were the first successful test of the fluorescent rod technique which is also
destined for W7-X and will have to be performed at a similarly high toroidal fields.
Visualised magnetic field lines for B0=0.45 T (left) and B0=2.0 T (right) in
hydrogen gas.
Scientific Staff
Measurements of the Absolute Magnetic Field Strength
During the plasma experiments on W7-AS a discrepancy
was quite often found between B0 calculated from the coil
R. Jaenicke, M. Otte
52
WEGA
Dr. Matthias Otte
Plasma Optimisation
On the classical stellarator WEGA experiments
have been focused on the optimisation of ECR
heated plasmas and the implementation and
testing of new diagnostics. Furthermore, a new
technique has been applied to make magnetic
field lines visible with the help of an electron
beam in a diluted gas.
plasmas were carried out. The
ion temperature obtained from
these measurements is about
1.5-2.0 eV which is by a factor
of about 3 to 5 smaller than the
electron temperature. The poloidal flow velocity of the helium ions is about 500-1000 m/s.
The results were cross-checked
with measurements from a high resolution spectrometer.
Furthermore, improvements on bolometer hardware have
been continued and a prototype of a neutral particle manometer which is foreseen for W7-X has been tested.
On the WEGA stellarator the
studies of the properties of ECR
heated plasmas at 2.45 GHz
have been continued. Using an
additional magnetron with a
power of 20 kW, in total 26 kW
microwave power is installed at
WEGA. In order to interpret the measured overdense plasmas an OXB mode conversion process is suggested. This
was supported by calculations of the full-wave equation by
E. Holzhauer, University of Stuttgart. The results show the
possibility of efficient conversion of O-wave launched from
the low field side with proper k-spectrum to X-wave near
the O-mode cut-off layer and a subsequent mode conversion
into an electron Bernstein wave at the upper hybrid layer.
Visualisation of Magnetic Field Lines
In preparation of the magnetic flux surface diagnostic on
W7-X a modified electron beam technique with the aim to
make magnetic field lines visible has been applied. The
method is based on the collisional interaction of an electron
beam with a highly diluted gas. As a result visible light is
emitted along the trajectory of a magnetic field line.
Optimum conditions in terms of visible length of the light
trace were obtained in argon and hydrogen at a pressure of
1.5×10-4 mbar, highest possible accelerating voltage of
450 V and maximum magnetic field strength of B0=0.5 T.
Up to 15 toroidal turns could be distinguished which equals
a length of about 65 m. In contrast to the measurements of
the magnetic flux surfaces using the electron beam technique and a fluorescent detector this new technique results
not only in a Poincar plot at a fixed toroidal position but
generates a detectable light signal in the whole vacuum vessel. However, only a limited number of toroidal turns of the
magnetic field lines are visible so that this method can not
replace the flux surface measurements but will provide additional information on the magnetic field structure.
Further details and results of this method are given in the
W7-AS section in this annual report.
Assuming this conversion process optimised ECRH antennae have been designed. By using these antennae a considerable fraction of microwave power is now deposited inside
the last closed flux surface (LCFS). It is planned to measure
the wave field in the assumed conversion region which is in
front of the antennae where an increase of the amplitude and
a decrease of the wavelength is predicted by the calculations.For global plasma characterisation an analysis of the
global particle and power balance was performed. By solving the particle balance equation, the particle confinement
time and diffusion coefficient D could be determined and
compared with theoretical estimates. It is found that D is
always above the neoclassical diffusion coefficient at the
edge of the confined plasma region.
Fluctuations may be responsible for this. The bulk electron
temperature profiles are usually hollow what could be simulated by solving the power balance equation inside and outside the LCFS. The main assumptions are, that the cold electrons are mainly heated through collisions with fast
electrons and the parallel heat conduction in the SOL is due
to the potential drop in the sheath in the vicinity of the vessel walls. A comparison of the energy confinement time of
slow and fast electrons with predictions from the ISS95
scaling law – assuming that the scaling is valid for both electron components – that the slow electrons are heated through
power transfer from fast electrons and a fraction of less than
20 % of the heating power is absorbed by the fast electrons
inside the LCFS. The existence of a two-temperature electron energy distribution could be verified by first soft X-ray
measurements.
Scientific Staff
J. Chung1, K. Horvath1, J. Lingertat, S. Marsen2, M. Otte,
Y. Podoba1
With the help of a new kind of 2D imaging modulated optical solid state (MOSS) spectrometer measurements of the
ion temperature and the poloidal flow velocity in helium
1International
2University
53
Max Planck Research School, Greifswald,
of Greifswald
ITER
ITER Co-operation Project
Head: Dr. Lorne Horton
The IPP contributes to the physics definition of
ITER via the International Tokamak Physics
Activity (ITPA). In this forum, the results of the
ASDEX Upgrade tokamak are compared to
those of other tokamaks. The ASDEX Upgrade
Team carries out a physics programme that is
directed towards the preparation of ITER. The
stellarator community also contributes to ITPA,
including experts from the Wendelstein Team.
Other IPP contributions are focussed on developing specific technical systems.
1 ITER Physics Performance
Prediction
plates, accepting image distortion in the toroidal direction (see
figure 1). A spatial resolution in
the millimetre range is possible.
In addition to the optical design,
the sensitivity and the dynamic
range of IR-systems measuring
in the near, mid and far IRregion was estimated. The
achievable time resolution in the
near and far IR-range is in the
order of a few tens of microseconds for optical systems with
moderate performance and a few hundred microseconds for
optical systems with rather bad performance at high temperatures. The effect of a structured surface on the measured temperature was also estimated. It depends on the wavelength and
the temperature itself. The error of the measured temperature
is below 10 % for the mid and far IR-range.
In the framework of the ITPA, in
order to improve upon simple
power-law scalings such as
ITERH-98P(y,2), the issue of
the errors in the regression variables has been revisited in order
to attempt to reconcile more single scan experiments. In particular, scaling expressions based
on the global confinement H-mode database ITER.DB3v13
α
α
α
of the form τ E / τ B ~ ρ* β ν*α q (where τE is the thermal energy confinement time, τB is the Bohm time, ρ* the (averaged)
normalised Larmor radius, ν* the collisionality and q the
plasma safety factor) as a function of the uncertainty in the
absorbed heating power and in Wth. From this it appears that
αβ can vary substantially, while for a variety of reasons still
some difference remains with the results from single scans.
The ITPA database does not, at present, contain sufficient
pellet discharges for an inter-tokamak analysis. In cooperation with Hungary (KFKI), an analysis of pellet penetration
depth was therefore performed on a high field-side dataset
(N=545) from ASDEX Upgrade, operating in a more or less
scaled-down ITER-like configuration. The normalised pellet
penetration depth l/a is expressed as a power-law in terms of
pellet mass mp, pellet velocity vp, plasma current and magnetic field, plasma temperature and plasma shape (elongation, triangularity). It is anticipated that this research is continued in the future by looking more precisely at the effects
of plasma shaping, temperature gradients and scalability
issues. The purpose of this work is to support diagnostic
preparation for ITER experiments as well as to increase
physics understanding.
ρ
β
ν
q
Figure 1: Implementation of the 1D optical imaging system for divertor
temperature monitoring. The blue line is the housing of the front end. The
toroidal depth is about 10 cm.
2.1.2 Bolometer Sensors
The prototype of a radiation hard resistive bolometer has
been produced and installed in ASDEX Upgrade. The present bolometer with a gold absorber and resistive meander
on either a Kapton or mica isolating substrate perform unreliably in an environment with the high neutron fluences
expected in ITER. The neutron thermal cross section of platinum is a factor 9 smaller than that of gold. The suspected
transmutation problem experienced with the gold meander
could therefore be delayed by substitution with platinum.
Silicon nitride is currently being investigated as one of a
number of ceramics to be used in ITER.
A silicon nitride film with 1.5 micron thickness is grown on
a 500 micron thick silicon wafer. The platinum meander,
with thicknesses of either 300 nm or 500 nm, was then sputter deposited onto the silicon nitride film. The silicon was
then etched away in the areas designated for the bolometer
foil absorbers. The absorber layer was deposited with thick-
2 Design of ITER Technical Systems
2.1 Diagnostics
2.1.1 Divertor Thermography
The conceptual design of a mirror-based relay optics was
developed. First, different access routes to the inner and
outer divertor were investigated including a tangential view
from the mid-plane, a view through the gaps between divertor cassettes and a view through the access hole in the middle of each divertor cassette. Using the access hole in the
divertor cassette would require the minimum number of
technical modifications at the divertor cassette and was thus
further investigated by developing an optical layout which
fits in between the cooling structures of the roof baffle as
shown in figure 1. The concept is optimized for a 1D system
measuring the temperature across the divertor (strike point)
57
ITER
nesses of 0.5, 1.0 and 1.5 microns using sputtered deposition
through a shadow mask.
The sensitivity of the prototypes is almost a factor of 3 better than the standard mica and gold foil. One bolometer head
with a prototype foil has been installed into the AUG tangential camera and signals obtained on all four channels.
(figure 2) together with a more controlled dispensing of Cs
has led to substantial increases of the ion current density,
and a more efficient suppression of the electrons without
large values of biasing. Calorimetric current densities of up
to 33 mA/cm2 accelerated H¯ in the right pressure range
have been achieved, which exceeds the ITER target
(28 mA/cm2) by about 20 %.
(iii) Short pulses in deuterium have been continued using a
remote control room: calorimetric current densities of up to
25 mA/cm2 accelerated D¯ ions have been reached, which
exceeds the ITER target (20 mA/cm2) by 20 %. These values
are well above those achieved so far with the source type
used in the ITER reference design. The recorded neutron
flux is still much lower than expected. The revised ratio
(measured yield / expected yield) turns out to be about a factor 25 lower than estimated from positive ion experiments.
(iv) The accompanying electron current can be largely suppressed using a sufficiently strong filter field and by achieving a favourable Cs deposition in the source. The ITER
requirement of iel/iion≈1 can already be achieved with the
present setup.
2.2 Heating Systems
The IPP makes contributions to the R&D of all three
planned heating systems for ITER: negative ion based neutral beam injection (NNBI); ion cyclotron resonance heating
(ICRH); and electron cyclotron resonance heating (ECRH).
In the area of ECRH, in addition to the physics studies
reported here, the IPP contributes to the design and testing
of the ECRH remote steered launcher through the IPP subassociation IPF Stuttgart.
2.2.1 Design of the ITER Upper ECRH Launcher – Physics
Integration
The studies on the performance of the ECRH Upper
Launcher in the framework of an EFDA activity were continued in 2004. IPP acted as leading Association for the
physics analysis. Since the main emphasis of the system is
on NTM stabilisation, the figure of merit is the localised
current driven by ECCD at the q=2 and the q=1.5 surfaces.
The reference design, based on remote steering, was found
to be marginally sufficient for (2,1) NTMs in the reference
Q=10 scenario, but below marginal for all other cases
(hybrid and low q scenario as well as (3,2) NTM stabilisation).
Several alternative designs as proposed during the study
have been evaluated as well. It was found that with remote
steering, some room for improvement exists, but a satisfactory performance for all cases is not predicted. Conversely,
the evaluation of a preliminary design based on front steering showed good performance in all cases, exceeding the
remote steering concept in the driven localised current by a
factor of 2-3. This is mainly due to the substantially reduced
spot size of the EC beam in the plasma with front steering.
Further work in 2005 will focus on analysis of new design
options, but also on the extension of the analysis to cases
with different toroidal field and q95 values.
Figure 2: View on the plasma grid, showing the reshaped masking plate
above the plasma grid and the bias plate. The masking plate has chamfered
holes and keeps a sufficiently large distance between the extraction area
and possibly disturbing installations.
Source diagnostics have been further improved. The negative ion density can now be derived from the Hα/Hβ ratio and
correlates well with the ion current (figure 3). The stripping
losses in the accelerator can be quantified by beam emission
spectroscopy. An example is shown in figure 4, where the
stripping losses are about 16 % (ITER 25 %).
Most of the physics experiments are carried out with a net
extraction area of around 70 cm2 on the BATMAN test bed.
On a second test facility (“MANITU” means Multi-Ampere
Negative Ion Test Unit), the experiments are focussed on
large area extraction up to the size, which is likely to be supplied by one RF driver in an ITER size source. The extrac-
2.2.2 Development of Negative RF Ion Sources
In 2004 the development of a large-area RF source for negative hydrogen ions, an official EFDA task agreement, has
made further substantial progress. The project is aiming at
demonstrating ITER-relevant ion source parameters, i.e. a
current density of 20 mA/cm2 accelerated D¯ ions from a
PINI-size extraction area for pulse lengths of up to 1 hour.
The major achievements on the BATMAN test bed are:
(i) With Caesium evaporation the source can now be operated reliably and reproducibly.
(ii) A new design of the geometry around the plasma grid
58
ITER
consistent with the results using the small 74 cm2 extraction
area on the Batman test bed at the same power level. With
306 cm2 the ion current density dropped only slightly but a
much smaller fraction reaches the calorimeter, basically
independent of the extraction voltage. This indicates that the
ion extraction is affected by the stronger magnetic field in
the outer parts of the extraction area, which are closer to the
filter magnets.
The main purpose of MANITU is the demonstration of long
pulses (3600 s). In preparing those activities, a high voltage
power supply and a 180 kW RF power supply for c.w. operation have been procured and are operational. Also the cryo
pumping system, being developed in collaboration with FZ
Karlsruhe, has been partly delivered and is nearing completion. Long pulse D– operation requires radiation shielding of
the test bed: the source and the extraction system is already
shielded by 20 cm thick polyethylene walls while the
calorimeter will be screened by 30 cm thick water tanks
placed inside the vacuum chamber.
A third test facility (“RADI”) is being constructed in order
to prepare a size-scaling demonstration. The new test facility
will be using one of the injector boxes of the decommissioned W7-AS injectors and is devoted to testing the geometry and the number of drivers as well the homogeneity of
large plasmas. It is scheduled to be ready for commissioning
in summer 2005. This source will roughly have the width of
the ITER source and half the height; its modular concept will
allow an extrapolation to the full size ITER source. Full size
extraction will not be possible due to limitations of the HV
power supply and the lack of a large size extraction system
and beam dump. The source will be equipped with a dummy
grid matching the conductance of the ITER source grid. The
RF power supply consists of 2 RF generators of 180 kW maximum power each with pulse lengths of up to 10 s. Both generators are currently being commissioned at IPP.
The main parameters determining the performance of the
source are the H– and electron density profiles across the
grid. These will be measured by spectroscopy, probes, laser
detachment and cavity ring down. These methods are/will be
calibrated to the extracted current density in BATMAN.
However, in order to get some information about the possible ion currents, local extraction with a Faraday cup system
from single holes is foreseen.
A substantial effort has been invested into diagnostic developments and modelling. The measurements of plasma flow
combined with the plasma temperature and density profiles
have been used to solve the one-dimensional fluid equation
of force balance. As a result the dependence of the gas pressure gradient on the plasma flow has been determined. By
using different transverse magnetic filed configurations, the
effect of this magnetic fields in slowing down the plasma
flow, and the effect of increasing gradients of the plasma
temperature and density profiles toward the extraction grid
Figure 3: Correlation between extracted current density and ion density
derived from spectroscopy
Figure 4: Beam emission from a H¯ beam showing the unshifted emission
(right), the emission from the full energy particles (left) and the emission
from stripped particles.
tion area has been enlarged by changing the grid masking
from the initially 74 cm2 in two steps to 152 cm2 (300 apertures in 185x249 cm2) and 306 cm2 (600 apertures in
228x340 cm2), the latter using the entire width of the plasma
grid. All three cases show a linear increase of the electrically
measured ion current density with extraction voltage. This
suggests that the driver is capable of illuminating extraction
areas up to 300 cm2 with sufficient plasma uniformity. With
10 kV extraction voltage and 100 kW a maximum value of
32 mA/cm2 corresponding to a total H– ion current of 9.7 A
has been measured at 0.45 Pa.
However, concerning the calorimetric current densities, the
situation is somewhat different. With 152 cm2 extraction
area a maximum H– current density of 19.3 mA/cm2 has
been achieved on the calorimeter at 90 kW RF power. This is
59
ITER
has been clarified. This set of measurements is complete and
can be used for validation of a fluid-dynamic code able to
predict the source parameters in new operational conditions
and geometry.
A diagnostic development that allows a direct measurement
of the H– density using optical absorption has been carried
out. By modulating the plasma density with an alternating
electric or magnetic field and simultaneously measuring the
small amplitude modulation of a transmitted light beam, the
optical absorption of the negative ions has been measured.
The absorption band extending in the visible and near
infrared spectrum is in good agreement with the theory and
the previous indirect determinations. The calibration of the
plasma density modulation results in a chord averaged negative ion density of the order of up to 10 % of the positive ion
density at a distance of 4.5 cm above the extraction grid and
in the best operating conditions.
Single particle orbit calculations of the extraction have been
performed: the results show that in the case of negative ions
produced on the plasma grid surface, the extraction process
has a relatively low efficiency due to the unfavourable
geometry where the initial ion velocity is in the direction
opposite to the extraction: only a corona of 2-3 mm thickness around the extracting hole will contribute. Substantial
progress can be achieved by optimising the plasma grid
extraction geometry, in a direction more favourable to the
extraction of the negative ions.
Apart from the rf source development, the scoping studies
on the magnetic ion removal system (“MIRS”) in the ITER
injector were continued in collaboration with Lublin
University, Poland. The present concept consists of magnetic
deflection of the residual ions to in-line dump plates with an
oblique incident angle (<14º). The in-line target plates are
hit only from one side and form a 0.5 m wide opening to the
beam. Thereby the geometric beam line transmission and the
injected power (1.7 MW per beam line for a 3 mrad beam
with the reference design parameters, figure 5) are increased,
leading to a wide operation window regarding beam alignment, perveance, transmission, divergence and steering.
Figure 5: Geometric beam line transmission for the different residual ion
dump systems (electrostatic – ERID, magnetic – MIRS) and different accelerator systems (the Japanese Multi Aperture Multi Grid System – MaMuG,
the European Single Aperture Single Gap System – SINGAP)
poloidal and toroidal straps in the antenna. For ITER antenna dimensions, the optimum width of the antenna strap is
about 1/2 of the housing width. Longer central conductors in
an ITER 4x4 array, as compared to a 6x4 array, lead to
improved coupling and a reduced voltage (for the same total
power input). It was also shown that part of the current strap,
close to the plasma, can be made out of rods (rather than
plates), thereby improving the pumping in the antenna, without affecting the k// spectrum.
A recent development for ICRF antenna design is the substantial progress in the commercial availability of electromagnetic codes allowing detailed analysis of the electrical
properties of an antenna. In a European effort, the different
codes will be benchmarked on a common, simplified model
of the ITER Antenna. IPP participates in this exercise by
providing the calculation using the HFSS (High Frequency
System Simulator) code.
Scientific Staff
ITPA: D. Coster, O. Gruber, S. Günter, H.-J. Hartfuß,
J. Hobirk, L. Horton, A. Kallenbach, K. Krieger,
K. McCormick, F. Ryter, G. Sips, W. Suttrop; Performance:
O. Kardaun, ITER Confinement and Performance Prediction
Working Group*; Diagnostics: L. Giannone, A. Herrmann;
ECRH: E. Poli, H. Zohm; NNBI: M. Bandyopadhyay
(IPR Gandhinagar, India), A. Encheva, H. Falter, U. Fantz,
P. Franzen, M. Fröschle, B. Heinemann, D. Holtum,
W .Kraus, C. Martens, P. McNeely, R. Riedl, J. Sielanko
(University of Lublin, Poland), E. Speth, A. Tanga,
R. Wilhelm; ICRH: W. Becker, D. Birus, V. Bobkov,
F. Braun, H. Faugel, D. Hartmann, G. Heilmaier,
J.-M. Noterdaeme, J. Wendorf, F. Wesner
2.2.3 Developments for the ICRH System
The ICRF test stand in Garching was used for further investigations of transmission line components for steady-state
operation. Al2O3 discs were also (in addition to AlN) confirmed to be suitable spacers for the inner conductors even
for the unmatched sections (VSWR>2) of the transmission
line system. The temperature rise of an uncooled inner conductor in an arrangement with a cooled outer conductor was
found to be sufficiently low (less than 150 °C mostly due to
convective cooling) to be used for the matched transmission
line sections (VSWR<2).
Calculations were made to investigate the trade-off between
length and width of the individual straps, and the number of
60
Fusion Technology
Plasma-facing Materials and Components
Head: Prof. Dr. Dr. Harald Bolt, Dr. Joachim Roth
Surface processes on plasmaexposed materials
Within the project “Plasma-facing Materials
and Components” the areas of plasma-wall
interaction studies, material modification under
plasma exposure, development of new plasmafacing materials and their characterisation have
been merged to form a field of competence at
IPP. The work supports exploration and further
development of the fusion devices of IPP and
also generates basic expertise with regard to
PFC-related questions in ITER and further
fusion reactors.
Chemical erosion of metaldoped carbon films
Magnetron-sputtered films consisting of carbon and metal (Ti,
V, W, Zr, Cr, Cu) were produced
with 0-20 at% metal concentration. The mixed layers were
characterised by RBS, SEM,
XRD and XPS, and films with
various concentrations of W, Ti,
and V were exposed to D3+ ions
of 30 eV/D at temperatures
between 77 and 1100 K.
The films are laterally homogeneously doped and show
columnar growth. The dopant distribution is not thermally
stable. After heating to 1100 K the carbides TiC, VC, WC,
ZrC, and Cr3C2 are definitely present and their grain size is
on the nanometre scale. Cu segregates out. Strong indications of the formation of carbides exist already during deposition.
The chemical erosion yield was investigated by mass spectrometry and RBS. Above RT (~300 K), the CD4 production
yield for pure C films exhibits a maximum around 750 K,
which decreases with increasing metal concentration. For
more than ~3 % W, ~6 % V and ~7 % Ti, the maximum vanishes and the CD4 yield continuously diminishes. Responsible for this decrease is a reduction of the activation
energy for ion-induced hydrogen release with doping.
Surface alloying in the Be-W
intermetallic system
The bimetallic system Be-W is
of special interest since both
metals shall be employed as
first wall materials in ITER.
Thin Be films on W are studied
after room temperature deposition and annealing experiments
up to 1070 K using in situ X-ray
photoelectron spectroscopy (XPS). If a reaction occurs, the
alloy Be2W is expected from the few existing phase diagram
informations. Already at room temperature an intermixing at
the interface occurs. Both in the Be 1s and the W 4f photoelectron signals peaks are observed which are assigned to
the formed Be-W alloy. The alloy peak in Be 1s has a binding energy of 111.1 eV, whereas the W 4f7/2 signal appears at
31.0 eV. At room temperature, the amount of intermetallic
compound increases with the amount of deposited Be up to
a coverage of approx. 4 monolayers.
Figure 1: X-ray photoelectron spectra during annealing of a Be layer on W
The behaviour of the Be films upon annealing depends on
the initial film thickness. For Be films up to a thickness off
1.4 nm the film thickness is not affected by annealing up to
970 K. Above 670 K, alloying sets in. The formed alloy is
stable during further annealing and at 970 K a Be 2W stoichiometry is measured. Between 1.4 and 3.0 nm, (figure 1),
the layer thickness decreases very fast and already during
the temperature ramp-up to the annealing temperature. The
remaining alloy thickness is 1.0 to 1.2 nm, being comparable
to the alloy thickness in the low coverage regime. Finally,
above a Be thickness of 3.0 nm the behavior is characterized
by a very slow decrease in Be thickness, starting at 670 K.
For different initial Be thicknesses above 3 nm, a Be-W
thickness of >1.4 nm remains. This thickness-dependent
behavior leads to the conclusion that the Be-W interaction in
the alloy is weaker than the Be-Be interaction in the pure
metal and leads to a pronounced loss in case of the thick Be
films.
Figure 2: Methane production yield of C layers doped with Ti and W versus
specimen temperature. For comparison, data for pyrolytic graphite and
pure C layer.
Enhanced erosion at high temperatures
For metals the theory of physical sputtering predicts very little change of the sputtering yield with temperature, proportional to the small changes of the surface binding energy
with temperature. At high temperatures the erosion rate
increases exponentially due to sublimation.
63
Plasma-facing Materials and Components
However, in recent experiments at the PISCES-B divertor
simulator at UC-San Diego thermally enhanced erosion was
found for metals. In these experiments Li, Ga, Be and Au
samples were exposed to a high flux (~1022 m-2s-1) low energy D plasma (~50 eV bias). It was found that for both solid
(Be, Au) and liquid (Li, Ga) metals the erosion rate
increased exponentially for temperatures at which normal
sublimation does not contribute significantly to the total erosion flux. This increase in erosion was accompanied by drop
in ejection speed of the eroded particles indicating an
increase in sublimation.
high flux particle bombardment and the annealing rate of
these defects. At low fluxes, typical for an ion beam experiment, the produced defects anneal too fast as to sublime in
sufficient quantities to contribute significantly to the thermally enhanced erosion and thus the experiment is dominated by conventional sublimation. In high particle flux environments like the divertor area of a fusion experiment
thermally enhanced erosion is most dominant.
Testing runs of the Dual Beam Experiment
A Dual Beam Experiment (DBE) has been designed for
study of erosion of candidate materials under simultaneous
bombardment with hydrogen isotopes and impurity projectiles. In addition, the new experiment allows in-situ ion
beam analysis of irradiated samples which provides information on the depth distribution of deposited and implanted
species in contrast to previous experiments where only the
weight change of samples could be measured. In first experiments, tungsten will be irradiated by ions of deuterium and
carbon.
The hydrogen ion source has been tested with deuterium
ions with energies varying from 3 to 10 keV with an energy
spread less than 25 eV. D3 ions, accelerated up to 9 keV, provide an achievable fluence of 1.4×1024 D/m2 that is sufficient for studying the effects connected to sputtering of
tungsten and its D retention. The sputter ion source has been
tested with carbon ions since this impurity is the most common in present fusion devices. Because of the principle of
operation, the system has a time variable beam current. The
total collected fluence of carbon atoms is about 6×1022 C/m2
using single negative ions accelerated up to 5 keV. For
increasing the C fluence and/or decreasing of the energy per
atom, it is possible to use various negative molecules of carbon up to C5−.
Figure 3: Comparison of Au erosion by a high flux D plasma and a low flux
D ion beam at elevated temperatures
In a model the sublimation of ad-atoms generated by the
impact of the energetic particles from the plasma is suggested as a possible mechanism to explain the observed effect.
Another explanation is that at high fluxes present in a plasma experiment the surface is oversaturated with D or He
atoms which leads to a reduction of the surface binding
energy and hence to an increase in sublimation. Both models
are based on the formation and sublimation of weakly bonded surface atoms due to defects generated by the high incident particle flux. The requirement of a high incident particle flux indicated by the models can explain the fact that
attempts to reproduce the thermally enhanced erosion of
metal by ion beams (4 orders of magnitude less flux) have so
far been inconclusive.
In figure 3 erosion of Au by a high flux plasma and a low
flux ion beam are compared. One can see that the effect of
thermally enhanced erosion is clearly visible in the plasma
experiment while in the ion beam experiment the measurement is dominated by conventional sublimation.
This behaviour can be understood based on the proposed
models. Generally, the intensity of thermally enhanced erosion depends on the interplay of defect production due to the
Improvements in the computer simulation of MeV ion beam
analysis methods
MeV ion beam analysis methods (such as Rutherford back
scattering, elastic recoil analysis and nuclear reaction analysis)
are powerful tools for the surface layer analysis of solids. A
computer code (SIMNRA) for the quantitative analysis of
spectra obtained with ion beam analysis methods was developed at IPP during the last seven years. This code is in use at
more than 100 laboratories worldwide. Recent code
improvements include an advanced surface roughness
model, a better treatment of scattering cross sections with
sharp structures (like nuclear resonances), modelling of
electronic effects (such as dead time correction and pile-up
simulation), and improvements of the cross-section data
library.
64
Plasma-facing Materials and Components
Migration of Materials in Fusion Devices
perature. This strong temperature dependence is attributed
to a strong temperature dependence of the re-erosion of
already formed layers by atomic hydrogen as observed in
laboratory experiments.
Carbon erosion and deposition on ASDEX Upgrade divertor tiles
Carbon erosion and deposition in the ASDEX Upgrade
divertor was investigated using a poloidal section of marked
divertor tiles and silicon samples below the divertor structure during the operation period 2002/2003. A poloidal set
of divertor tiles was coated at TEKES/Finland with a marker
stripe consisting of a thin Re marker layer and a C layer on
top. The whole inner divertor is a net carbon deposition area,
while a large fraction of the outer divertor is erosion dominated and the roof baffle tiles show a complicated distribution of erosion and deposition areas. In total, 43.7 g B+C
were redeposited, of which 88 % were deposited on tiles and
9 % in remote areas (below roof baffle, on vessel wall structures). 0.6 g C was pumped out as volatile hydrocarbon molecules. Identified carbon sources in the main chamber are
the outer wall protection limiters. However, the measured
carbon influx from these limiters is too low by a factor of ten
to explain the observed carbon divertor deposition. Carbon
erosion is observed at the outer divertor strike point tiles, but
it is not clear if material can be transported from the outer
strike point to the inner divertor.
Figure 4: Temperature dependence of the thickness of codeposited layers
below roof baffle of ASDEX Upgrade
Tritium Inventory – Understanding and Control
Deuterium inventory in ASDEX Upgrade
The long term deuterium retention in ASDEX Upgrade was
studied by ion beam analysis of a poloidal section of lower
divertor tiles and long term samples in remote areas (below
roof baffle, in pump ducts, behind inner heat shied, etc.).
D is mainly trapped in codeposited, deuterium-rich hydrocarbon layers in the inner divertor, especially at the inner
strike point and on tiles just opposite to the inner strike
point. The D/C ratio of these layers ranges from 0.5 to 0.9.
Only small amounts of D are trapped in the outer divertor.
Deuterium-rich layers with D/C from 0.4 to 1 are also
observed below the divertor roof baffle. In total, 2.4 g deuterium were trapped inside the vessel during the discharge
period 2002/2003. The majority (about 75 %) are trapped on
the tiles of the inner divertor, and about 25 % in remote
areas (below roof baffle etc.). The total deuterium input into
plasma discharges by gas puffs, neutral beam injection and
pellets was about 77 g for the whole discharge period. The
observed deuterium trapping inside the vessel is therefore
only about 3 % of the total deuterium input.
Co-deposition of deuterium with carbon in gaps of plasmafacing components
The tungsten baffle and divertor wall components for ITER
will be manufactured as macrobrush structures with tungsten rods bonded at the rear side to a cooled base structure.
There are concerns that large tritium inventories may form
in the gaps between the W rods. To investigate this process,
a tungsten macrobrush limiter with gap parameters similar
to those of the ITER design was exposed to the boundary
plasma in about 40 subsequent ASDEX Upgrade discharges.
At the retrieved probe the amount of deposited D was measured using Nuclear Reaction Ion Beam Analysis. It turns out
the fraction of D deposited in the gaps is of the same order
than the amount of D deposited at the surface. Because the
probe was close to room temperature during exposure, additional studies are necessary to investigate how the D-inventories in the gaps scale with increasing temperature.
Temperature dependence of hydrocarbon layer formation in
remote areas
Redeposited hydrocarbon layers are formed in remote areas
of ASDEX Upgrade, such as below the divertor roof baffle.
The temperature dependence of the hydrocarbon layer formation was studied with heated long term samples below the
roof baffle during the discharge period 2003/2004. The sample temperature was varied from room temperature to
200 °C. The observed layer thicknesses decrease with
increasing sample temperature. The layer deposition is
smaller by a factor of about 50 at 200 °C than at room tem-
Tritium inventory in ASDEX Upgrade
Deuterium and tritium deposition in the divertor of ASDEX
Upgrade was measured by analysis of a tile set retrieved
from the vessel after the experimental campaign 2002/2003.
Deposited deuterium was quantified by Nuclear Reaction
analysis at the accelerator laboratory of IPP. In addition,
implanted tritium isotope, which originates from D-D reactions in the plasma discharge, was quantified by accelerator
65
Plasma-facing Materials and Components
mass spectroscopy at the accelerator laboratory of the
Technical University of Munich. This technique allows in
addition to obtain depth profiles of the implanted species.
Like previously observed at main chamber wall samples, the
depth distribution of both species is different and reflects the
origin of the deposited isotopes. Deuterium is found to be
deposited at the surface, mainly in form of co-deposits with
carbon. The tritium depth distribution extends to deeper
regions of the surface corresponding to higher impact energy of the order of the plasma core temperature. This shows
that the implanted tritium atoms were not thermalised with
the cold boundary and divertor plasma upon impact. In addition to the depth profiling, tritium inventories in the divertor
were studied by exposure of imaging plates, which detect
the bremsstrahlung of the electrons from T beta decay. The
distribution of tritium found in ASDEX Upgrade agrees
with that found in similar studies in JT 60U where tritium
single particle simulations using the OFMC code explain the
distribution pattern as a result of orbit and ripple losses.
Garching high current ion source. It allows to measure the
permeating flux through thin metal foils at temperatures
between room temperature and 600 °C. First successful test
measurements with stainless steel foils were performed.
Materials – Processing and Characterisation
Oxidative erosion of carbon materials
For cleaning procedures of in-vessel components from codeposited hydrocarbon layers with oxygen, the oxidative
erosion behaviour of the carbon base materials has to be
known. This was investigated for seven types of graphite by
heating in air at temperatures between 600 and 1000 K. The
specimens included pyrolytic graphite, fine grain graphites,
carbon-fibre compounds (CFC), and graphites doped with
Si and Ti. Measurements include the weight loss using a
micro balance, the surface topography using scanning electron microscopy, and the composition of the surface layer
using MeV ion beam techniques.
Pyrolytic graphite was least affected by erosion, while pure
and Si-doped CFCs erode particularly fast. Typical erosion
rates for specimens were below 2⋅10-10 kg/m2s for all types
at 600 K and at 900 K 3.4⋅10-7 kg/m2s for pyrolytic graphite
and about 9⋅10-6 kg/m2s for strongest eroding types. The
temperature dependence of the erosion rate of all types of
graphite is well described by an activation energy of 1.75 eV.
All together, the oxidative erosion of the carbon base material is more than one order of magnitude lower than for amorphous hydrocarbon layers deposited from low temperature
plasmas and 2-4 orders of magnitude lower than for codeposited layers from fusion plasma devices.
Hydrogen isotope permeation barrier coatings
To provide a means for the active control of hydrogen isotope permeation into and through metallic components of
fusion reactor systems, thin ceramic coatings have been
investigated for several years. After the successful reduction
of deuterium permeation through EUROFER steel by three
orders of magnitude in 2003, two further leading branches
of work were commenced in 2004: In cooperation with the
National Institute for Fusion Science and the University of
Tokyo, Erbium oxide coatings were produced for application
in a liquid lithium breeder environment. These were tested in
2004 with respect to their performance as an alternative
hydrogen diffusion barrier. It was found that a permeation
reduction similar to alumina coatings can be obtained – at
identical thicknesses reduction values of about 30 % to 50 %
of the performance of alumina were obtained. In addition,
the application of alumina diffusion barriers under even
more realistic conditions was pursued: Alumina coatings on
EUROFER are now covered with a tungsten top layer – only
a coating buried with a realistic plasma-facing material is a
realistic application for a first-wall component of a fusion
reactor. This will, however, affect the dissociation behavior
of the hydrogen gas. Measurements of the resulting barrier
performance are on the way.
Metal matrix composites
Novel copper matrix composites reinforced with silicon carbide long fibres are being considered as a new generation of
heat sink material for the divertor of future fusion reactors.
The reinforcement of copper with SiC fibres leads to a higher strength of the composite in relation to unreinforced
material. Following the rule of mixture the calculated tensile
strength is 800 MPa for a composite with a fibre volume
content of 20 %. If the composite is utilised in the highest
thermally loaded zone at the interface between plasma facing material (C or W) and heat sink (CuCrZr), the plasma
facing component may withstand higher temperatures especially at the interface of up to 550 °C. These high temperatures are necessary for efficient energy production of future
fusion power plants.
SiC fibres (SCS6, Specialty Materials) were electrolytically
coated with a 80 µm thick copper layer and hot isostatically
pressed in a copper capsule to form the composite material.
A sputter deposited 100-nm-thin titanium interlayer between
SiC fibre and copper matrix improved the bonding properties. In cooperation with DLR (German Aerospace Center)
Hydrogen permeation through metals by ion bombardment
Energetic hydrogen ions and atoms are able to penetrate the
surface barrier of metals. After slowing down in the material, they start to diffuse through the metal lattice. This ion
driven permeation can exceed gas driven permeation by several orders of magnitude. In order to investigate ion driven
permeation of deuterium through candidate first wall materials, a new experimental set-up was commissioned at the
66
Plasma-facing Materials and Components
tensile tests at room temperature were carried out. The
determined tensile strength ranged from 600 MPa for a composite with a fibre volume fraction of 15 % to 870 MPa for a
composite with a fibre volume fraction of 30 %. The tested
pure copper without fibre reinforcement had a tensile
strength of 200 MPa. The fractured surface of the composite
specimens without additional titanium interlayer shows
pulled-out fibres due to poor adhesion between fibres and
matrix (figure 5a). For composites with titanium interlayer
no fibre pull-out behaviour was observed (figure 5b).
component will be subjected to low cycle fatigue due to
ratchetting.
Plasma sprayed tungsten coatings on stainless steel substrates
The development programme of vacuum plasma sprayed
tungsten coatings on low activation steels, EUROFER,
F82H, as well as stainless steel 316L was accomplished in
2004. The aim was the evaluation of the feasibility of such
coatings as plasma facing material for expected heat loads
of 0.5-1 MW/m2 on first wall components in ITER or
DEMO. The 2 mm thick W-VPS coatings, ~20 % porosity,
were deposited on a mixed W/steel interlayer to improve the
coating adhesion. Thermal tests of EUROFER and 316L
mock-ups (outer dimensions: 60x190 mm2) were carried out
in the JUDITH facility at FZ Jülich. In the frame of a cooperation with JAERI one F82H mock-up was tested in the
electron beam test facility JEBIS. All coatings survived long
pulse and cyclic heat load tests up to 2.5 MW/m2 without
any changes or damages.
The measured thermal conductivity of the W coating is
20 W/mK at room temperature and 31 W/mK at 1000 °C is
in the same order of magnitude of the substrate materials.
As a result of D-retention measurements, it can be concluded that the accumulation of hydrogen at the surface of such
porous W-VPS coated components in plasma operation is
limited to an acceptable value. A further optimisation of the
VPS processing parameters should reduce the porosity of
the layer and the distinct layered structure of not completely
molten W particles.
In the framework of EFDA Technology Work Programme
2004, a task in the field of Plasma Facing Materials, a set of
testing methodologies was developed and verified to identify the elastic modulus of the highly porous tungsten layers
(1.5 mm thick) coated on a EUROFER steel substrate. A
simple testing procedure was to be developed which can be
conducted on a radioactive specimen in a hot cell after irradiation test. To this end, the minimum specimen size should
be determined which guarantees that the specimen can be
charged into an irradiation rig capsule without loosing the
validity of the measured elastic modulus values.
The developed testing methods were based on three point or
four point bending tests. Non-local homogenised elastic
modulus values have been measured using four different
identification methods and three different specimen sizes.
The measured values ranged from 51 to 57 GPa for the large
specimen (51×181 mm2) whereas they were between 57 and
63 GPa for the intermediate specimen (25×90 mm2). The
standard deviations were less than 2 GPa. The modulus of a
detached coating was determinded to 54 GPa. As the methods are independent from each other, the results reveal that
the employed methodology and the specimen system were
reliable and reproducible. Experiment with a small specimen (12×90 mm2) is under way.
Figure 5: Fractured surfaces of a composite without (a) and with titanium
interlayer for a better bonding between fibre and matrix (b)
Shakedown analysis of the fibrous copper matrix composites
Fibrous copper matrix composite with continuous ceramic
reinforcements has been considered as a candidate material
for high heat conducting heat sink of divertor components.
The composites should maintain sufficient strength and
dimensional stability at elevated temperatures up to 550 °C.
Under certain combination of temperature change and cyclic
loads, an elasto-plastic structure with non-uniform stresses
can undergo a progressive plastic deformation from cycle to
cycle, although the load amplitudes are fixed. This phenomenon is called ratchetting. On the other hand, such a ratchetting is suppressed after a limited number of load variations,
if the ratchetting condition is not fully satisfied. In this case,
it is said that the structure shakes down.
In this work package, shakedown limits (i.e., ratchetting
conditions) of the fibrous copper matrix composites were
determined using the discretised shakedown analysis. This
method is based on the static shakedown theorem combined
with finite element method and large scale non-linear optimisation technique. Both uni-axial laminar and cross-ply
laminate architectures were analysed assuming various combinations of thermal and mechanical loading cases. The
computed shakedown envelopes were compared with corresponding elastic limits of the composites.
In the case of the cross-ply laminate under a bi-axial loading
mode, the shakedown limits were just slightly larger than
elastic limits. According to the structural analysis of the
composite component, the loading path by a typical fusion
operation will notably exceed the shakedown limits.
This means that the copper matrix composite in a divertor
67
Plasma-facing Materials and Components
W-Si as Plasma-facing Material for Fusion Reactors
Under accidental conditions, intrusion of oxygen into the
reactor chamber may occur. Combined with a loss-ofcoolant event (LOCA) the temperature of tungsten PFC
might rise to 1100 °C due to nuclear decay heat. Radioactive
and highly volatile WO3 compounds may form and reach the
environment.
W-Si compounds form protective SiO2 layers in events of
high heat oxidation and prevent the formation of volatile
WO3 oxides. In previous experiments it was demonstrated
that a sub-stoichiometric WSi0.45 compound starts forming a
protective SiO2 film on the surface above 600 °C reducing
the oxidation rate of W by a factor of 100 above 800 °C.
An addition of Cr further reduces the oxidation rate especially in the low temperature region, where an addition of Si
alone cannot provide protection. The sputter-deposited
WSi0.82Cr0.45 material reduces the oxidation rate by more
than three orders of magnitude already at 600 °C as determined from the weight loss in thermobalance measurements.
to offer an additional European HHF test facility for the
tests of full scale ITER divertor components.
Component Behaviour
Scientific Staff
IPP high-heat-flux test facility
The construction of a new facility for the testing of plasma
facing components (PFC) under high heat fluxes was completed in 2004. The aim of this facility is to provide thermal
testing capabilities for high heat loaded divertor components
which have both active water cooling and large outer dimensions. The water-cooled test chamber (figure 6, diameter
1.5 m, length 3.7 m) is equipped with 2 ion sources for positive hydrogen ion beam production. Initially, only one of the
two individually controlled RF ion sources with 1.1 MW
maximum beam power will be used for heat loading tests.
After the commissioning and calibration of the facility, the
testing of W7-X pre-series target elements will start.
Approximately 10 % of nearly 900 manufactured target elements will be individually tested with heat loads of up to
12 MW/m2.
For these first tests of individual elements it is possible to
use unmodified ion sources from the former W7-AS with
reduced power and increased pulse length. In parallel to
these activities, the operation of an improved, water cooled
ion sources starts in 2005. This allows an effective examination of the thermal, hydraulical and thermo-mechanical
behaviour of completed W7-X target modules consisting of
10-13 elements arranged in parallel and mounted onto a
frame with outer dimensions up to 0.6×0.8 m2.
After the completed HHF tests of individual elements and
modules, more than 20 % of all target elements will be
examined with heat loads relevant to the expected operation
until end of 2007. After completion of the testing of the
W7-X plasma facing components, it should then be possible
Ch. Adelhelm, V. Alimov, M. Balden, A. Beikler, M. Ben
Hamdane, I. Bizyukov, A. Brendel, B. Böswirth, H. Bolt,
B. Cieciwa, J. Chen, J. Dorner, W. Eckstein, K. Ertl,
M. Fußeder, K. Gehringer, A. Golubeva, H. Greuner,
T. Höschen, R. Hoffmann, W. Hohlenburger, A. Holzer,
Ch. Hopf, E. Huber, W. Jacob, E. de Juan Pardo, B.Y. Kim,
J. Kißlinger, K. Klages, F. Koch, T. Köck, K. Krieger,
R. Lang, A. Leinthaler, D. Levchuk, S. Levchuk, S. Lindig,
Ch. Linsmeier, H. Maier, K. Marx, G. Matern, P. Matern,
M. Mayer, M. Meier, M.A. Miskiewicz, I. Quintana Alonso,
B. Plöckl, C. Popescu, M. Reinelt, M. Roppelt, J. Roth,
F. Sardei, J. Schäftner, K. Schmid, T. Schwarz-Selinger,
M. M. Spychalski, R. Straßer, A. Weghorn, A. Wiltner,
M. Ye, J.-H. You Contributors: W. Bohmeyer, J. Boscary,
M. Laux, R. Neu, H. Renner, V. Rohde, S. Schweizer
Figure 6: HHF test facility under construction. View to the open door and
the test chamber
68
Energy and System Studies
Head: Dr. Thomas Hamacher
1 Objectives
The global energy development turns out to be
of prime importance for the possible future
development of fusion. The energy and system
study group did therefore continue to work on
global energy models and the underlying
methodologies. Work on urban energy systems
and more detailed technical issues complemented the work.
The energy and system studies
group evaluates possible future
developments of the energy system. The role of fusion plays a
central role in the investigations. Looking into the future of
fusion requires a rather long
time horizon. This needs of
course very special care of the methodologies applied.
Developing these methodologies is one of the major focus of
the group. Global scale investigations are necessary to catch
all the problems and interrelations in the energy system
properly, especially because resources are distributed worldwide, the demand development can only be understood on a
2.1 VLEEM
The Very Long Energy and Environmental Model (VLEEM)
tries to establish a new methodology based on a back-casting
approach. The back-casting
approach is well suited to discuss possible trajectories to a
sustainable development. Several pictures of the future are
Figure 1: A very futuristic picture of an energy system from the VLEEM
project shows the result of which relies only on solar and wind power. The
whole world is connected by a large electricity grid. This makes it possible
Figure 2: The above figure shows the electricity production by fuel in a
future energy scenario with cumulative CO2 emission constraints.
to smooth the seasonal and daily fluctuations of wind and solar power.
designed which fulfil certain – mainly sustainability – criteria. The pictures are designed according to paradigms or
clusters of possible future technologies. It is assumed that
these technology families dominate the energy system in a
way like oil and the internal combustion engine dominates
the system today. In a second step a possible trajectory from
the future end-point to the present system is drawn.
global level and environmental impacts are globally. On the
other side smaller scale and more technical investigations
are necessary. The local level shows specificity’s, which
could be easily overlooked working on a global scale. And
some very technical issues like the future development of
the electricity and gas network need very special considerations.
This year a software tool was developed to track back the
future state to the present time. The software tool called
BALANCE is a simple energy model based on the modelling software GAMS. The processes are modelled at a high
aggregation in space and time and the major purpose of the
model is to get all the “book keeping” in respect to resources, installations and emissions correct. Already before
energy models were developed to treat energy systems with
intermittent and very dispersed generating capacities. These
models were used to develop end-points.
2 Global Energy Models
The group is engaged in two major European studies: SocioEconomic Research on Fusion (SERF) which is co-ordinated by EFDA and the Very Long Energy and Environmental
Model (VLEEM). Both projects develop pictures of the
future global energy system. The SERF project uses the
state-of-the-art energy modelling generator TIMES, while
within the VLEEM project new modelling tools were developed.
2.2 Models with TIMES
The simple one regional global energy model prepared by
IER of the University of Stuttgart was refined and special
69
Energy and System Studies
cases with and without fusion were investigated. The model
was especially used by our Austrian guest scientist. They
developed further features especially the possibility to
include endogenous learning and price elastic demands.
Both concepts are important to model the economic reality
more in detail. At the end of 2004 a new multi-regional energy model was supplied by EFDA to all fusion associations.
This model will be refined in the next years and will serve
as a major tool to analyse the chances and challenges
nuclear fusion will face in the future.
the climate protection programme for the city of Greifswald
and the European ESCOBALT project.
4.1 Vienna
The city of Vienna decided in 2004 to perform a special programme on energy savings. The city formed a consortium
between the TU-Wien, the Energie Verwertungs Agentur
(EVA), the company IRM and the IPP. The major role of the
IPP is to develop an energy model of the city of Vienna with
the modelling tool Message. A first model is under preparation. The model will be especially suited to model the new
European emission trading scheme.
2.3 India
The co-operation with India is of special importance to work
with the multi-regional global model. Experience gathered
in the co-operation with the Indian Institute of Management
in Ahamedbad will be used to operate the new multi-regional model with realistic inputs.
4.2 Greifswald
In spring 2004 the city of Greifswald decided to investigate
together with the IPP the possibility to reduce greenhouse
gas emissions in Greifswald. As a first step a greenhouse gas
emission balance is under preparation.
The balance should on one side follow conventional statistical approaches and shows the emissions in the different sectors: household, services, industry, traffic and public sector.
Beside this more refined emission maps will be prepared.
3 Future energy networks
The investigation of energy networks, especially electricity
and gas, is of prime importance to understand future developments. Beside the co-operation with the University of
Rostock to develop pictures of the future German electricity
network, work was started to investigate the future development of the global natural gas infrastructure. This work
should contribute as a satellite model to the multi-regional
energy model in TIMES.
Figure 4: Estimates of the CO2-emission balance for the city of Greifswald
4.3 ESCOBALT project
The ESCOBALT project focuses on urban energy systems in
the Baltic Sea region. Emphasise of the project is to understand who the new EU member states can transform urban
energy infrastructure like district heating.
Figure 3: First results from the ProToG model show interregional gas
streams in South America.
Scientific Staff
M. Baumann*, K. Behringer, M. Biberacher, J. Düweke,
C. Eherer*, T. Farid, T. Hamacher, S. Richter, S. Winkelmüller
4 Urban energy systems
We would especially like to acknowledge the financial support of the Friedrich Schiedel Stiftung for the guest scientists.
In co-operation with the university Augsburg (here the EPP
and WZU), further investigations in the field of urban energy systems were done. The work is focused in the three projects: the energy savings programme for the city of Vienna,
*guest scientist, Technical University Graz
70
Plasma Theory
Theoretical Plasma Physics
Heads: Prof. Dr. Sibylle Günter, Prof. Dr. Karl Lackner
Tokamak Physics Division
Head: Prof. Dr. Sibylle Günter
To exploit the unique situation of our institute
as a centre both of tokamak and stellarator
research, the first-principle based model developments within the institute have been united
into a project “Theoretical Plasma Physics”. It
combines the corresponding efforts of the
Tokamak Physics and the Stellarator Theory
Divisions and of the Junior Research Group
“Computational Studies of Turbulence in
Magnetised Plasmas”, and is headed by one
theorist on the board of scientific directors.
asymmetry. Increasing density
was observed to affect the 13C
asymmetry. The introduction of
a recycling/deposition model
which favours C recycling
above a specified electron temperature, and deposition below
this temperature was able to
give the observed levels of C
deposition asymmetry. The
drifts are then observed to have
a strong effect by changing the
target electron temperature
asymmetry, with the reversed field case having a much
lower predicted C deposition asymmetry.
Tokamak Edge Physics Group
Work in this group has mainly
centred on the use and further
development of the SOLPS
code package. This package includes a 2D fluid description of
the plasma (usually used for the
edge) and either a kinetic or a
fluid treatment of the neutrals.
Amongst the enhancements to the code is a module to calculate neoclassical transport. The code has been used in the
last year to simulate disruptions, C flows in the edge,
H-mode and Ohmic shots. Furthermore, there is an effort to
benchmark SOLPS and EDGE2D-NIMBUS. In addition to
the activities described below in some detail we have performed also SOLPS5 simulations with and without drifts for
ITER, and made contributions described in the AUG and the
JET chapters.
Scrape-off Layer Turbulence Simulations
In joint work of the edge physics and turbulence groups, the
model behind the GEM3 turbulence code was extended to
treat the locations where the magnetic field lines intersect
the material limiter/divertor plates. Debye sheath physics
concepts were used to model the interaction of the plasma
with the plates. The results revealed the dominance of a convective cell mode (k||=0) whenever the limiter was included
and an associated increase of the turbulent transport. The
effect of the ASDEX Upgrade divertor geometry was investigated by performing turbulence simulations comparing a
simplified and the real magnetic geometry. On closed field
lines, the real geometry exhibited a reduction of the turbulent transport compared to the simplified case (which
retained only the poloidal dependence of the curvature operators). These results stress the importance of using faithful
descriptions of the tokamak geometry, especially if comparisons with the experiment are aimed for.
Disruption Simulations
While the code is usually used to simulate the edge plasma,
it has also been used with a grid extending to within a few
centimetres of the magnetic axis. One such application is to
simulate the thermal quench phase of a disruption. A predisruption plasma is simulated using sources of particles
and energy derived from an ASTRA simulation of a particular ASDEX Upgrade discharge, and transport coefficient
profiles derived from fitting to the experimental temperatures and densities. The disruption is then modelled by
enhancing the transport coefficients in the whole plasma by
a factor based on a Rechester-Rosenbluth magnetic braiding
ansatz. The computed rise and decay time scales for the
divertor power fluxes after a disruption show a significant
dependence on the gas puff puffing rate, with a rather clear
transition from symmetric target fluxes to asymmetric target
fluxes associated with a concommitant change-over from
conductive to convective divertor behaviour.
MHD Theory Group
Error field amplification
In the advanced tokamak scenarios, plasma performance is
strongly limited by the external kink mode. This mode can
be stabilised by plasma rotation, but at the same time error
fields (for instance asymmetric perturbations produced by
the magnetic coils) can strongly amplify the mode and stop
the plasma rotation. Thus, the investigation of the error field
amplification is a key issue for enhancing plasma performance. Linear MHD codes can be used to investigate these
resonant processes. During the last year, the CASTOR code
has been improved and extended and allows now to calculate
directly the error field amplification (relation between magnetic perturbations near the plasma boundary with and without the plasma). A comparison of this version of the CASTOR code with the linear MHD MARS code has been
started.
Simulation of carbon flows in the JET edge plasma
In order to try and understand the observed carbon deposition patterns at JET (where both the intrinsically produced C
and C puffed from the top of the machines is found at the
inner target rather than the outer), SOLPS simulations were
done with D+12C+13C+He, with the 12C arising from chemical and physical sputtering, and the 13C from a gas puff at
the top of the machine. In the simulations, transport ballooning, the position of the D gas puff and the presence and
direction of drifts did not strongly affect the C deposition
73
Theoretical Plasma Physics
growth rates (numerical evaluation of the Landau-pole-integrals). The eigenvalue formulation of LIGKA allows to calculate self-consistently the coupling of large-scaled MHD
modes to the gyroradius-scale kinetic Alfvén waves which
can result, e.g., in the appearance of kinetic-TAE modes
slightly above the TAE gap or in coupling to the “discretised
continuum” near the edge. Benchmarks with fluid-codes
(CAS3D-K) and other gyrokinetic codes (PENN) for TAEcases have been started. So far, for global TAE modes
roughly the same damping rates as calculated by fluid codes
were obtained and no indication for mode conversion of
kinetic Alfvén waves in the centre of the plasma – as proposed by PENN – has been found.
Extended linear MHD studies: toroidal rotation, viscosity, current
holes, and resistive walls
The linear magnetohydrodynamic stability of ideal and
resistive, axisymmetric toroidal equilibria has been investigated with respect to various additional physics effects, such
as differential toroidal rotation, viscosity, resistive walls, and
extreme reverse shear situations (current holes), by corresponding extensions of the CASTOR code. In case of fast
toroidal rotation the dependence of the equilibrium density
on the poloidal coordinate is taken into account. Static and
stationary equilibria, including equilibria with current holes
serve as input to this code called CASTOR-FLOW. As an
application the stabilising effect of differential toroidal rotation on double tearing modes (DTMs) has been studied up to
a toroidal Mach number of 0.5. Sufficiently high viscosity
and differential toroidal rotation were found to lead to its
stabilisation. The stability of DTMs has also been studied
for equilibria with current holes.
While the CASTOR-FLOW code is restricted to axisymmetric equilibria and wall geometry, the extended CAS3D code
solves the linear MHD stability problem for 3D equilibria in
the presence of an arbitrarily shaped multiply-connected,
ideal or resistive wall. The stabilising effect of a resistive
wall on an external ideal kink mode has been investigated,
and a benchmark between the CASTOR-FLOW code and
the extended CAS3D code has been made. The electromagnetic model used for the 3D-structure of the resistive
wall has also been tested against the leading code for treating electromagnetic induction and diffusion problems
through rigid toroidal structures (CARIDDI), giving excellent agreement.
Our main tool for the study of nonlinear, resistive (incl. neoclassical) MHD in cylindrical approximation, is the TM1code. It uses a Fourier decomposition in poloidal and
toroidal direction, and had been significantly improved in
the accuracy of the treatment of heat conduction by the
implementation of a self-adjoint formulation of the finite
difference approximations. An equivalent, similarly accurate
formulation was also found for the case of a finite difference
treatment of both coordinates in the poloidal plane. We have
also investigated with TM1 the effect of a m/n=12/4 helical
field on the m/n=3/1 tearing mode, to compare with corresponding experimental observations on TEXTOR. It is
found that when the amplitude of the 12/4 helical field is
sufficiently large, the 3/1 mode is stabilised by the 12/4 he−
lical field, in agreement with the experimental findings.
Transport Analysis Group
The group studies neoclassical as well as anomalous transport. Below three topics (the polarisation current around
moving island structures, electron heat transport, and particle transport) are discussed in more detail.
The studies of kinetic effects on neoclassical tearing modes
with guiding centre Monte Carlo particle simulations have
been continued. For these modes the polarisation current
which arises from the rotation of the island can have,
depending on its direction and size, a stabilising effect. The
transition of this current from the low to the high collisionality limits is found to occur in agreement with recent analytic
theory. In present Tokamak plasmas the (higher) collisional
limit is not likely to be obtained.
In contrast to fluid theory the polarisation current is found to
change sign when the rotation frequency is close to the product of the parallel wave vector with the thermal velocity.
This effect is closely related to the precession drift of the
trapped ions. If the frequency ω is close to the diamagnetic
Kinetic effects on MHD modes
The ability to predict the stability of fast-particle-driven
Alfvén eigenmodes in burning fusion plasmas requires a
detailed understanding of the dissipative mechanisms that
damp these modes. The linear gyrokinetic MHD code
LIGKA has therefore been extended to deal with negative
Figure 1: Comparison of the measured electron heat flux with quasilinear
gyrokinetic results (arbitrary scaling factor in the saturation level included)
as function of the normalised electron temperature gradient
74
Theoretical Plasma Physics
frequency, as predicted by analytic theory, then ω/k||vth can
be close to unity. This effect is therefore of importance to
assess the strength of the polarisation current stabilisation.
Comparisons of the electron heat transport in low density
plasmas with quasilinear gyrokinetic (GS2) calculations
have been completed and are summarised in figure 1. Here
an arbitrary factor has been used to model the saturation
level of the turbulence. The calculations clarify several
experimental observations that have been discussed in the
literature. Specifically, they show the existence of a threshold and reveal a moderate stiffness in the electron channel.
The calculations also show that the heat flux above the
threshold is almost linear in the normalised gradient – a
result that is useful for the further interpretation of experimental observations.
The study of particle transport focused on the investigation
of the causes of the observed density flattening with central
electron heating in low collisionality plasmas. Gyrokinetic
calculations confirmed previous fluid results showing that
an increase of the electron temperature in the TEM instability domain implies a flattening of the density profile. The
theoretical results have motivated us to devise and perform a
set of experiments in L-mode plasmas in ASDEX Upgrade,
to test the effect of an increase of electron heat flux on the
density profile, at different levels of collisionality. These
experiments also allowed us to relate the observations on the
particle with those on the electron heat transport. A rather
complete and consistent understanding of the observed phenomena, in both the particle and heat transport channels, has
been obtained with the help of accurate gyrokinetic calculations of the micro-instability producing the largest transport
in the different plasma conditions obtained in the experiments. – The linear gyrokinetic calculations of particle
transport have been extended to multi-species problems,
with the help of a new procedure to compute the quasilinear
fluxes which has been found to yield results in rather good
agreement with nonlinear gyrokinetic results. It has been
found that collisionless ITG and TEM instabilities induce
impurity anomalous inward pinches which are weaker than
those of the Deuterium, and consequently, that theory of
anomalous particle transport predicts that in collisionless
plasmas the impurity profiles are less peaked than those of
the main ions.
package i2mex and the transport package TRANSP.
The extension of TORIC to deal with Lower Hybrid waves
has given first results, which agree well with those obtained
with the “beam tracing’’ approach by G. Pereverzev. They
confirm that refraction due to toroidicity is sufficient to
explain the spectral gap paradox and produce complete
absorption in a single transit in situations when ordinary ray
tracing would predict multi-transit to be required. This code
is being parallelized by the MIT group to allow applications
to large tokamaks.
Theory of Ion Cyclotron antennas
In the frame of the collaboration with the JET team, we have
analysed the experimental data of the 2003 campaign concerning the IC antenna coupling. The analysis confirms the
strong dependence of the JET antenna resistance on the
equatorial antenna-plasma distance, and a weaker dependence on the asymmetry between upper and lower antennaplasma distances. We have obtained a good agreement
between the measured time evolution of the resistance and
the prediction of a simple model using the density profile
monitored by the Lithium Beam diagnostics and the reconstructed magnetic field of the discharges. This analysis has
motivated a revision of the semiempirical formula commonly used to describe the dependence of the coupling efficiency on the thickness of the evanescence layer between the
antenna and the low-density cut-off.
Driftkinetic and Gyrokinetic Theory
We have made several contributions to the foundations of
drift-kinetic and gyrokinetic theory. – In applying the
Noether formalisms with gauge-invariant variations we have
developed a new method for directly obtaining in a very
straightforward way the symmetric energy-momentum tensor for an important class of gauge-invariant Lagrangian
densities. – Poisson brackets in the phase space of averaging
coordinates have been obtained in a direct way using a
gyroangle-independent Lagrangian. The usual cumbersome
procedure of matrix inversion to obtain the Poisson tensor
from the Lagrange tensor is not required. – Methods and
results were derived within the framework of a gauge-invariant theory concerning local conservation laws for the density of gyrocentres and the charge, energy, momentum and
angular momentum. The symmetric energy-momentum tensor, which describes the correct energy and momentum densities and their corresponding flux densities, was obtained.
All conservation laws are cast in a very clear form affording
insight into their structure. – We have also investigated the
consequences of choosing special gauges or gauge-invariant
or non-gauge-invariant approximations in the action integral
for the variational formulation of theories involving electromagnetic fields, in particular two-fluid, driftkinetic and
gyrokinetic theories.
Wave Physics Group
The code TORIC, which solves Maxwell equations for waves
in the ion cyclotron (IC) range of frequencies in toroidal
geometry, has been integrated into a package which allows a
more complete simulation of IC heating and current drive
experiments in tokamaks. Also included in the package are
the module which evaluates the quasilinear diffusion coefficient for the electrons needed for the simulation of current
drive experiments, and interfaces to the tokamak equilibrium
75
Theoretical Plasma Physics
The principal reason for this difference to edge turbulence is
the absence of robust nonlinearity in the passing electrons,
which for core parameters are nearly adiabatic except near
the kinetic ballooning threshold.
The confluence of ITG and TEM dynamics for general
parameters (strength of the density and temperature gradients measured by the ratios of their scale lengths to the
toroidal major radius) explores the particle pinch phenomenon and temperature profile stiffness (which in the electrons
can only be explained by the trapped fraction). The ratio of
the scale lengths for zero particle flux is in close agreement
with the linear GS2 cases currently being used by the
Transport Group to study particle and impurity transport in
ASDEX Upgrade. The interesting finding physically is that
the particle pinch (transport against a finite density gradient,
driven by the temperature gradient) is principally in the
trapped component, overcoming the tendency of the passing
component to be transported down the gradient. The thermal
flux is, of course, down the gradient. This situation had been
very difficult to capture in turbulence models in the past.
Numerical Methods
We have considered an equation describing the anomalous
transport of heat in tokamaks, characterised by a jump in
diffusivity when the temperature gradient exceeds a certain
threshold. The integration range is split into two sub-ranges
according to the value of the temperature gradient below and
above the threshold, and the equation is solved simultaneously in each segment with moving boundary. – The existence of unique solutions to a system of equations modelling
electron beams in gyrotron resonators was shown for short
time intervals. The investigation of efficient difference
schemes for these and other evolution equations was
continued.
Turbulence Theory Group
Our studies of the low frequency fluid-like drift turbulence
believed to underlie anomalous transport in magnetically
confined fusion experiments continue. We employ fluid
models extended to capture important kinetic effects
(Landau damping, finite gyroradius), and kinetic models
intended to treat all phenomena at the scales of interest
(1 mm to 10 cm, 10 kHz to 1 MHz). The latter models are
called gyrokinetic. Both fluid and gyrokinetic models have
been recast within the past two years for greater accuracy
within a wider set of parameter regimes. The gyrofluid
model is called GEM and the gyrokinetic model GENE.
Both are fully self consistent, treating several particle
species and the electrostatic and shear-Alfvén magnetic
potentials through which they are coupled.
Studies of Zonal Flows and Impurity Transport in Edge Turbulence
using the GEM Code
The gyrofluid model was introduced about 10 years ago to
treat core turbulence, but the concurrent realisation that
edge turbulence also involves gyroradius scales motivated
our first electromagnetic gyrofluid model about 5 years ago,
and its improvement since early 2003 to allow robust edge
turbulence (steep gradients, strongly nonadiabatic passing
electrons) at all scales including the electron gyroradius.
This GEM model has been used in 2004 to study zonal
flows and impurity dynamics in edge turbulence in runs
with up to four species (electrons and a D/T/He ion mix).
Edge turbulence zonal flows are in general not as dominant
as for the classic core cases, for the reason that nonlinear
drift wave physics (see earlier reports) produces very strong
vorticity at scales of a few ion gyroradii which can always
compete with the self generated zonal vorticity. The geodesic acoustic oscillation, a result of toroidal compressibility of
the zonal flows, is very slow relative to the edge turbulence,
by contrast to the core situation. Edge turbulence sees even
this zonal flow component as static and is hence able to
remove the zonal flow energy.
Concerning the impurities we find a pinch or exhaust tendency depending more on the temperature/charge (T/e) ratio
than the mass/charge (m/e) ratio, owing to the importance of
toroidal drifts entering through the geodesic curvature effect
on zonal flows as well as the interchange effect on the turbulence. There is a “dynamical alignment” phenomenon
according to which two nominally independent fields,
whose dominant effect is turbulent advection, tend to evolve
towards each other in morphology, as the part which is different is dissipated at small scale. In hydrodynamics this is
Studies of Core Turbulence using the GENE code
The upgrades in accuracy and two-species self consistency
to the GENE code have been completed, and the principal
effort has been the application to tokamak core turbulence in
regimes where ion temperature gradient (ITG) and trapped
electron mode (TEM) drive mechanisms are dominant. This
is the first study of this type of turbulence with fully
resolved computations, which are among the largest electromagnetic gyrokinetic ones ever attempted. The grid of
128x128 ion gyroradii in the perpendicular plane approaches global scale for the ASDEX Upgrade core region.
Both pure ITG and pure TEM cases have been studied, by
switching off the trapping or the ion temperature gradient,
respectively. In the ITG cases all the principal results of the
Cyclone study were reproduced, including the sensitivity to
zonal flows. By contrast, the pure TEM cases find little or
no sensitivity to zonal flows. A simple model constructed
from these cases using form factors from the linear mode
structure is able to capture the transport trend of the turbulence cases: core turbulence in general retains much of the
features of the underlying linear mode structure, with the
spectrum peak near the peak of the linear mixing length estimate spectrum.
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Theoretical Plasma Physics
Stellarator Theory Division
studied in terms of the density and vorticity fields. The
result with impurities is the tendency of every species to
mimic the morphology of the electron density, with very
high degrees of cross correlation observed even in the
absence of direct coupling. This tends to pinch an impurity
density until its gradient equals that of the electrons. The T/e
sensitivity then enters such that lower values (i.e., helium)
tend to be preferentially exhausted, a favourable finding
with respect to reactor situations.
Head: Prof. Dr. J. Nührenberg
Introduction
In 2004, the work of the Stellarator Theory Division was
concentrated on widening the scope of the theoretical work
at the Greifswald Branch Institute1 and on further development of the stellarator concept2, notably for quasi-isodynamic configurations.
Fully Nonlinear, Inhomogeneous Gyrofluid and Gyrokinetic Equations
It is necessary to relax the “δf ” approximations currently
used in all tokamak turbulence codes world-wide up to now.
Our efforts to generalise the gyrofluid model to relax this
local limit using Lagrangian field theory methods has been
extended to the anisotropic pressure case, and in 2005 will
be further extended to include dynamical parallel heat fluxes, at which point it will be ready to replace the current
GEM model.
A companion to the GENE code, using the methods in GEM
to apply the gyrokinetic model to the edge, has been constructed. A fully nonlinear “full-f ” model using the above
field theory methods will finish construction and enter testing and production in 2005.
Development of Stellarator Concept
In 2004, the collaboration between NFI (Kurchatov) and IPP
continued within a WTZ agreement. With a confinement
system with qualitatively new confinement properties having been identified3, the emphasis in 2004 was on integrated
optimizations. In particular it was shown that a configuration with six periods and aspect ratio twelve can show a
high-β (〈β〉=0.085) non-local-mode MHD stable equilibrium with very good fast-particle collisionless confinement,
low neoclassical ripple and negligible bootstrap current, see
figure 2.
Scientific Staff
C. Angioni, M. Apostoliceanu, G. Becker, A. Bergmann,
R. Bilato, M. Brambilla, A. Chankin, Y. P. Chen, D. CorreaRestrepo, D. Coster, T. Dannert, K. Dimova, M. Götz,
S. Günter, V. Igochine, F. Jenko, O. Kardaun, A. Kendl1,
C. Konz, K. Lackner, P. Lauber, P. Martin, P. Merkel,
R. Meyer-Spasche, G. Pautasso, A. Peeters, G. Pereverzev,
S. Pinches, E. Poli, T. Ribeiro, B. Scott, W. Schneider,
E. Schwarz, M. Spannowsky, D. Strintzi, E. Strumberger,
G. Tardini, H. Tasso, C. Tichmann, Q. Yu, R. Zille
Figure 2: Structural factor of the bootstrap current in the long-mean-free-path
regime for the configuration described above in comparison to equivalent
axisymmetric and approximately quasi-helically symmetric configurations
Guests
C. V. Atanasiu, Institute of Atomic Physics, Romania,
M. Foley, University College, Cork, Ireland,
P. McCarthy, University College, Cork, Ireland,
G. J. Miron, Institute of Atomic Physics, Romania,
A. Perona, Politecnico di Torino, Italy,
G. Poulipoulis,University of Ioannina, Greece,
E. Quigley, University College, Cork, Ireland,
G. Sias, RFX Consorzio, Italy,
G. N. Throumoulopoulos, University of Ioannina, Greece
MHD Theory of Stellarators
Island compensation coils in WENDELSTEIN 7-X
Proper formation of the natural-island chains near the plasma edge is essential for optimum divertor operation in
W7-X. The additional inclusion of Island Compensation
Coils (ICCs) would allow for (i) the magnetic compensation
1V.
1University
Kornilov et al.: PoP 11, 3196 (2004); D. Morozov et al.: NF 44, 252
(2004); A. Mishchenko et al.: PoP 11, 5480 (2004); V. Kornilov et al.:
PPCF 46, 1605 (2004); M. Warrier et al.: CPP 44, 307 (2004)
2R. Kleiber et al.: NF 44, 172 (2004); V. Nemov et al.: PPCF 46, 179
(2004)
3M. Mikhailov et al.: NF 42, L23 (2002)
of Innsbruck
77
Theoretical Plasma Physics
Figure 4: The critical βfast/β from CAS3D-K vs. the ratio of maximum beam
velocity to Alfvén velocity which constitutes a stability limit. The dashed
line marks the critical βfast without the electron damping, the ellipse the
experimental conditions.
Figure 3: Current loads for a 10-trapezoidal-ICCs compensation system
(odd subfigures) and a 10-helical-ICCs system (even subfigures) in kA as
evaluated for error-fields from (i) coil rotation (CR), (ii) bad coil-shape
(CS), and (iii) module misalignment (MM). In the W7-X standard case
(2.78 T at 1.6 MA/modular coil) the relative magnitude of the leading errorfield harmonics is 2-3x10-4.
(TAE’s) and energetic particle modes (EPM’s) has been
explored at LHD. A drift-kinetic extension of the ideal magneto-hydrodynamic (MHD) stability code CAS3D has been
calculated for realistic 3D conditions (W7-AS shot No.
39042) considering the contribution of circulating particles.
The drift-kinetic MHD growth and damping rates of a fastparticle driven TAE mode have been calculated and compared to an analytical theory6, which considers strongly
localized modes in the large aspect ratio limit and only the
largest contributions to the growth rate caused by circulating
particles. Varying parameters as ion β and maximum beam
velocity, stability diagrams have been calculated. The results
indicate that this particular shot is close to marginality.
These theoretical stability diagrams open up a possibility for
more comparisons with the experimental exploration of the
parameter space. It has been shown7 that resonances stemming from 3D coupling contribute to the ion damping whereas
the fast particle drive comes mainly from the 1/3 vA side-band
resonance. The electron contribution to the damping is small,
see figure 4, because the electron velocity is larger than the
Alfvén velocity.
of the most important perturbations (1/1, 2/2, and 3/3) that
could arise from errors in coils manufacturing or positioning, and for (ii) controlled studies of the effect of errorfields in W7-X plasmas. With a Singular Value Decomposition method and the use of a control surface the current
loading for two different systems of Island Compensation
Coils (ICCs) has been determined. Both of them located
outside the cryostat, each of the systems comprises ten individual coils. A set of helical coils was more effective than a
trapezoidal-coils set, needing the lower individual (<6 kA)
coil currents for an approximate restoration of the magnetic
fields4 (see figure 3).
Ideal MHD Stability
With a further extension of the CAS3D stability code in
2004, now a tool is available for the determination of general toroidal plasma equilibria by perturbation theory. The
force density of the plasma in the magnetic field has a component perpendicular to the magnetic surfaces that modifies
the shape of the surfaces. This change is calculated by
CAS3D by balancing the force density across the magnetic
surfaces with the ideal MHD force of Delta-W stability theory. In this way, the consequence of a deviation of a plasma
state from an MHD equilibrium (either pressure or surface
perturbation) can be studied5.
ITG & Drift Wave Theory of Stellarators
ITG driven instabilities are likely to be one main mechanism
to drive turbulence leading to anomalous transport in the
core of magnetically confined plasmas. Drift-wave turbulence is held responsible for plasma edge turbulence.
MHD-Stability with kinetic Effects
Generalized gyrokinetic solver
The influence on MHD modes of fast particles whose confinement in burning plasmas is essential, has been investigated experimentally not only for tokamaks, but also for
stellarators, as e.g., in W7-AS. Recently, the parameter
space for the exitation of toroidal Alfvén eigen modes
Global gyrokinetic particle simulations have proven to be a
promising approach to describe the field fluctuation-driven
transport in fusion devices. In particle codes, one discretizes
the quasineutrality equation using finite elements, finite differences or spectral techniques. The long-wavelength approximation is commonly used in finite-element codes
4C.
6Y.
Nührenberg et al.: 31st EPS 2004, (P1-202)
Boozer et al.: 46th Annual Meeting of the Div. of Plas. Phys. 2004,
JP1.067
Kolesnichenko et al.: PoP 9, 517 (2002)
Könies: Workshop on Theory of Fus. Plas. 2004, “Growth and damping
rates of Alfvén eigenmodes using kinetic MHD”
5A.
7A.
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Theoretical Plasma Physics
which implies a second order Taylor expansion of the polarization density with respect to the parameter kzρi. This
approximation is accurate enough only if kzρi<1 and can
neither address ETG modes nor TEM instabilities. A method
which can be used at arbitrary small scales has been developed. The polarization density being an integral over the
phase space, is calculated using “numerical particles” (not
to be confused with the marker particles used in the charge
assignment). Integrals over the gyro-angle are calculated
using the N-point approximation. We have verified our
method in a shearless slab where the linear analytical dispersion relation can be derived (see figure 5). Additionally, we
apply the solver in a more complex two-dimensional bumpy
pinch configuration where both, the linear small-scale ITG
and ETG modes have been simulated.
Figure 6: TORB results in screw-pinch geometry with ι=0.2: field energy
(F), negative kinetic energy (K), heat flux (Q), and measure of energy conservation (C). Computation parameters: 227 markers; time-step: 40 inverse
gyro-frequencies (1/3 µs); spectrum of electrostatic potential:(m,n) 0
[-80,80]x[0,16]; optimized loading.
transform for equilibria with tokamak-like shear resulted in
nearly no influence on the zonal flow strength while for stellarator-like shear the strength significantly increased. For
both signs of the shear the turbulence level strongly
decreased. Turbulence calculations for W7-X showed that
finite-β effects of the equilibrium lead to only a slight
decrease in the particle and heat fluxes which are already
small at zero-β. The 3D global linear gyrokinetic code
EUTERPE has been extended in order to allow computations of electrostatic ITG modes for finite-β equilibria.
While the most unstable ITG mode1 for the vacuum W7-X
equilibrium is mainly curvature driven, shows a broad
Fourier spectrum and is highly localized toroidally as well as
poloidally an increase in β (mainly causing a deepening of
the magnetic well) leads to an increase in slab drive until for
〈β〉≈4 % a slab mode with only one main spectral component
is found. This strong change in mode structure is accompanied by only a small decrease in the growth rate of the mode.
The eigenvalue code for global ITG modes in general geometry based on the Braginskii equations9 has been tested for
tokamak cases where it reproduced the usual ballooning
structure of the modes. In an application to the vacuum
W7-X equilibrium only slab-like modes (with finite parallel
wave number) but not the curvature-driven mode found earlier in the gyrokinetic calculations with EUTERPE could be
identified.
Figure 5: The growth rate of the ITG and the ETG modes in a shearless slab vs.
ky. Rectangles are used for the simulation results and the solid line for the solution of the dispersion relation. The plasma is inhomogeneous in the x-direction
with κTiρI=κTeρI=0.022 and κn=0. The wave numbers kxρi=0.023 and
kzρi=7.43x10-4.
Global ITG turbulence in screw-pinch geometry
Turbulence in the geometry of a straight cylinder as a first
simplified model of the W7-X stellarator has been investigated with the gyrokinetic global non-linear particle-in-cell
code TORB (CRPP/IPP). In 2004, TORB8 was further
extended to include the influence of a finite rotational transform in zero-β straight-cylinder geometry. For low, zeroshear rotational transform (ι=0.2) reliable results with good
energy conservation were obtained (see figure 6). As in the
zero-ι case, a zonal flow develops which limits the heat flux
due to the turbulence. The maximum heat-flux levels of the
two cases approximately coincide.
Plasma Edge Physics
Plasma modeling
Scrape-off layer code
Using the DALF-Ti code for turbulence calculations of the
boundary plasma the influence of shear and rotational transform on the strength of zonal flows in axisymmetric configurations has been investigated. Increasing the rotational
The 3D fluid transport code BoRiS simplified the adaption
procedure to arbitrary geometries by introducing the complete metric tensor in the algorithm. Changing geometries
reduces then to pre-processing of the grid and the metrics.
An automatic time stepping control was prepared in order to
8S.
9V.
Drift Wave Turbulence in Stellarators
Sorge: PPCF 46, 535 (2004)
79
Kornilov et al.: PPCF 46, 1605 (2004)
Theoretical Plasma Physics
500
minimize computational effort and to improve numerical
stability.
450
100
400
Modelling of heat conductivity in the DIII-D poloidal divertor in
presence of non-axisymmetric perturbations
50
External non-axisymmetric perturbations of the magnetic
field created by the control coils may have a significant
influence on the operation of the tokamak poloidal divertor.
In the DIII-D tokamak such coils are used for error field
correction (C-coil) and MHD-mode control (I-coil) in the
core plasma. This perturbation destroys the divertor separatrix and leads to the ergodization of the magnetic field lines
in the pedestal region and in the scrape-off layer thus causing the loss of the magnetic flux from the region inside the
former separatrix. Here, we studied the additional heat
transport due to the magnetic field ergodization using the
3D fluid Monte-Carlo code E3D10. Figure 7 shows the electron temperature profile. The perturbation field strongly
affects the pedestal region of the plasma. It produces a
plateau region near q=3-4 and essentially reduces the temperatures at the inner boundary in the case of a fixed incoming heat flux. The heat load distribution around the outer
strike point of the divertor plate shows a characteristic bifurcation observed experimentally, too.
350
Z [cm]
300
0
250
200
-50
150
100
-100
50
50
100
150
200
250
300
R [cm]
Figure 7: Electron temperature, eV, in the asymmetric case (φ=0°).
A diffusion coefficient without knowledge of the material
structure is meaningless, because the void sizes and distribution determines this number to a large extent.
Sputtering
A 2D/3D extension of the dynamical version of the binary
collision code SDTrim SP was developed. With this tool,
dynamical changes of the surface composition and structure
can be studied.
Complex Plasmas
A P3M (Particle-Particle, Particle-Mesh) code was developed which is able to describe self-consistently, e.g., the
charging of nano-particles in a plasma. Here, the traditional
Particle-in-Cell method (PM) is combined with Molecular
Dynamics (PP) to resolve effects below the Debye length.
Scientific Staff
M. Borchardt, M. Drevlak, G. Kervalishvili, R. Kleiber,
A. Könies, V. Kornilov, K. Matyash, A. Mishchenko,
N. McTaggart, C. Nührenberg, J. Nührenberg, J. Riemann,
A. Runov, R. Schneider, S. Sorge, M. Warrier.
Computational Material Research
Hydrogen transport in graphite
It is important to understand hydrogen isotope transport in
graphite in order to evaluate the use of graphite as a first
wall and divertor target material in fusion devices. The
graphite used in fusion devices as first wall material is
porous and consists of granules and voids. These granules
are typically 1-10 µm and consist of graphitic micro-crystallites of size 10-100 nm separated by micro-voids. There
exists a wide variety of interaction possibilities between the
hydrogen isotopes and the substructures of graphite like
inter-crystallite diffusion, trans-granular-diffusion and surface diffusion, adsorption-desorption and trapping-detrapping on the internal surfaces. The hydrogen isotope transport in graphite therefore occurs over time scales from
pico-seconds to seconds and length scales from angstroms
to centimeters in a porous 3D complex geometry. A general
multi-scale method was developed to model hydrogen isotope transport over such a wide range of scale lengths and
time in a complex 3D porous geometry using Molecular
Dynamics, Kinetic Monte-Carlo and Monte-Carlo diffusion.
Guests:
X. Bonnin (Paris Uni.), A. Boozer (Columbia Uni.),
B. Braams (Emory Uni. Atlanta), M. Donath (Uni.
Münster), Y. Hundur (Istanbul Tech. Uni.), M. Isaev
(Kurchatov Inst. Moscow), P. Lalousis (IESL FORTH
Crete), M. Mikhailov (Kurchatov Inst. Moscow), Y. Pan
(Southwestern Inst. of Phys. Chengdu), D. Reiter (FZ
Jülich), V. Rozhansky (State Tech. Uni. St. Petersburg),
E. Salonen (Uni. of Helsinki), I. Senichenkov (State Tech.
Uni. St. Petersburg), A. Subbotin (Kurchatov Inst. Moscow),
C. Suzuki (NIFS), F. Taccogna (Uni. di Bari),
S. Voskoboynikov (State Tech. Uni. St. Petersburg),
R. Zagorski (Inst. of Plas. Phys. and Laser Microfus.,
Warsaw), A. Zvonkov (Kurchatov Inst. Moscow).
10A.
80
Runov et al.: NF 44, 74 (2004)
Theoretical Plasma Physics
Junior Research Group
similarity hypothesis in MHD turbulence, a key assumption
inherent in many intermittency phenomenologies.
Head of Project: Dr. Wolf-Christian Müller
Turbulent magnetoconvection
Turbulence driven by temperature gradients is a general phenomenon in nuclear fusion experiments as well as in the
astro- and geophysical context.
Parallelized spectral simulation codes have been developed
which allow studying thermally-driven three-dimensional
hydrodynamic and MHD turbulence(Boussinesq approximation) in classical Rayleigh-Bénard configuration and in
fully periodic geometry.
After successful preliminary testing on convection in neutral
fluids, examination of the influence of buoyancy and magnetic fields on turbulent dynamics has begun.
Homogeneous MHD turbulence
Following the development and successful numerical verification of a theoretical description of the nonlinear interplay
between kinetic and magnetic energy in incompressible
magnetohydrodynamic (MHD) turbulence, two setups have
been studied as paradigms for the presumably most important realizations of this system with regard to the energy cascade: statistically isotropic flows with kinetic and magnetic
energy in approximate equipartition and turbulence permeated by a strong mean magnetic field.
While the first case exhibits well-known behaviour in accordance with hydrodynamical Kolmogorov phenomenology,
the anisotropic case displays bi-dimensionalization in planes
perpendicular to the mean field direction (as expected) and
Alfvénic energy cascading (unexpected and in disagreement
with currently accepted theory). After having demonstrated
the latter behaviour by means of high-resolution direct
numerical simulations, investigation of the associated transition of nonlinear mode interaction is under way.
In collaboration with the group of S. Chapman (University
of Warwick) and R. Dendy (Culham Science Centre) it has
been shown by analysis of numerical simulation data that an
earlier proposed Log-Poisson intermittency model for velocity and magnetic fields in incompressible MHD turbulence
also describes the statistics of energy dissipation.
This finding represents the first confirmation of the refined
Compressible turbulence
Compressible MHD turbulence is assumed to be an adequate description for the state of, e.g., the inter-stellar medium and the convection zone in certain types of stars, in particular in the sun.
After acquiring the parallel three-dimensional FLASH simulation code from the ASCI/Alliances Center for
Astrophysical Thermonuclear Flashes (University of
Chicago), the program, which contains a well-tested core
able to deal with compressible MHD flows, is currently
extended with spectral diagnostics and turbulence driving
mechanisms necessary for numerical experiments.
Lectures
Kaskaden, Selbstorganisation und Struktur magnetohydrodynamischer Turbulenz, Frühjahrstagung des Deutschen
Physikalischen Gesellschaft, Kiel
Fundamental Properties of Magnetohydrodynamic Turbulence via Large-Scale Numerical Simulations, 31st EPS
Conference on Plasma Physics, London
Energy Dynamics, Structure, and Anisotropy of Turbulent
Magnetofluids, University of Rome “La Sapienza”, Rome
Scientific staff
Yuriy Zaliznyak, Dan Skandera
MHD turbulence permeated by a strong mean magnetic field (three-dimensional numerical simulation). Field lines are adumbrated in blue. 2D-contours show the amplitude of magnetic fluctuations from dark red (low) to
white (high).
81
Basic Plasma Physics
Centre for Interdisciplinary Plasma Science
Heads: Prof. Dr. Dr. h.c. Volker Dose, IPP, Prof. Dr. Dr. h.c. Gregor Morfill, MPE
Low-temperature Plasma Physics
of N2+ ions with a-C:H surfaces
causes chemical sputtering similar to H2+ ions alone. In principle, this effect is known from
literature, but so far, there has
been no systematic investigation of its energy dependence.
If the a-C:H surfaces are exposed to a simultaneous flux of
N2+ ions and atomic hydrogen,
we find a significantly enhanced erosion. The agreement
of the data with the chemical sputtering model is acceptable,
but the measured yield is systematically higher than the
model predictions. This deviation might be due to the chemical activity of nitrogen.
In summary, we can state that the combined interaction of
atomic hydrogen and energetic ions leads to a synergistic
enhancement of the sputtering yields called chemical sputtering. In addition to the enhanced yields, the energy threshold for chemical sputtering is much lower than for physical
sputtering. A microscopic mechanism for chemical sputtering was developed. Based on this microscopic mechanism
we devised a mathematical model, which allows a quantitative description of the ion energy and ion species dependence of chemical sputtering in the presence of excess supply
of atomic hydrogen. The agreement of this chemical sputtering model with experimental results is excellent for the case
of noble gas ions (Ar, Ne) and reasonable for the case of
chemically active species (H2+, N2+).
The Centre for Interdisciplinary Plasma Science
was founded for a five years period with effect
of January 1st 2000 by the Max-Planck-Institut
für extraterrestrische Physik und Max-PlanckInstitut für Plasmaphysik. The aim of the collaboration was to strengthen complementary
research activities in complex plasmas, theoretical and numerical plasma science and scientific data analysis. This section reports on the IPP
share in the centre’s activity.
The Low-temperature Plasma
Physics group (LTPP group) at
IPP is concerned with the application of low-temperature plasmas for surface treatment, such
as deposition of thin films, erosion, and surface modification.
The main focus is on the investigation of plasma-surface interaction processes of hydrogen
and hydrocarbon plasmas (e.g. CH4) with hydrocarbon
films. These processes play an important role in the transport of carbon in the boundary layers of fusion experiments.
Basic studies of thin-film erosion processes
Synergistic erosion of C:H surfaces by energetic neon ions and
thermal hydrogen atoms
In recent years, the combined interaction of argon ions and
atomic hydrogen with amorphous hydrogenated carbon
(a-C:H) layers was investigated. For this process, termed
chemical sputtering, a model was devised to describe its
energy dependence. New experiments with neon ions were
performed. In general, the same observations as for argon
are made. Interaction of the ions alone (physical sputtering)
is well described by TRIM.SP calculations. The combined
interaction of ions and H cause an erosion rate that is much
higher than the sum of the individual processes. A prediction
that is solely based on the model parameters fitted to the Ar
data is in excellent agreement with the Ne data. It is further
interesting to note that the rates for Ar and Ne are very similar although the masses of both species differ significantly.
This is a consequence of the change in the collision cascade
due to differences in stopping power, penetration range, and
cross section for nuclear collisions. These effects are inherently included in the model due to the simulation of the collision physics by the TRIM.SP computer code. The new
neon data represent an excellent confirmation of the devised
chemical sputtering model.
Inductively-coupled plasma device for in-situ growth studies
In a new plasma experiment set up in 2001, the plasma is
produced by inductive coupling at a frequency of
13.56 MHz. In this device, the deposition of a-C:H layers
from pulsed discharges is investigated. One aim of this work
is to identify the main growth precursors that contribute to
the growth of amorphous hydrocarbon (a-C:H) films in
pulsed methane discharges. Growth and erosion of layers are
investigated by real-time, in-situ ellipsometry. In addition to
the plasma monitor used to detect ions and neutrals impinging on the substrate surface a molecular beam mass spectrometer allows to determine the fluxes of reactive radicals
to the chamber walls.
Quantitative measurements of the ion and methyl radical
fluences to the substrate show that these species contribute
only about 10 % to the growth. The observed growth can
only be explained by highly reactive radicals, which do not
need any surface activation of the film for incorporation.
These species can either be formed directly from the source
gas or from heavier hydrocarbons (CxHy, x>1). The highly
reactive radicals C and CH have, however, also a high reaction rate coefficient for gas phase recombination with CH4,
Chemical sputtering with molecular nitrogen ions
In addition to the experiments with noble gas ions, where
the energetic species are chemically inert, we started first
experiments using molecular nitrogen ions (N2+) as chemically active ion species. In contrast to the case with noble
gas ions, the erosion due to N2+ ions alone cannot be explained by TRIM.SP calculations. The erosion yields are
significantly higher than the predicted physical sputtering
yields and show in contrast to them no clear energy dependence over a wide energy range (50 to 900 eV). This is a clear
signature of chemical sputtering. We conclude, interaction
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Centre for Interdisciplinary Plasma Science
Data Analysis
which produces either stable or less reactive species. We find,
therefore, substantially lower growth yields for higher pressures. In addition to the densities of the stable CxHy molecules
with 1≤x≤4, the radicals CH3 and CH2, and the ion fluences
per pulse are measured. Comparing the absolute gas densities
with growth rates global carbon and hydrogen balances are
inferred. From the measured CH3 density the fluences per
pulse to the substrate of the radicals C, CH, CH2 and CH3 are
deduced. From the gas densities of C2H2, C2H4, and C2H6 the
fluences to the substrate of the radicals C2H, C2H3 and C2H5
are estimated. The growth contributions of the ions and the
different radicals are obtained by multiplying the fluences
with the corresponding sticking coefficient.
The Data Analysis group at IPP is concerned with analyzing
experimental data. Modern techniques of data analysis have
to be applied whenever the inferential problem is ill-posed,
different sources of information have to be combined, or
model choice or model uncertainty is an issue. Scientific
reasoning is generally based on uncertain measurements and
(vague) prior information from previous knowledge about
the system of interest. Bayesian probability theory (BPT)
provides a general and consistent frame for combining various kinds of information taking into account the degree of
uncertainty of data, parameters and models.
Contribution of different species from the plasma to the growth of a-C:H
layers. The sum of the individual contributions is in good agreement with
the measured growth per pulse.
Integrated data analysis
The concept of Integrated Data Analysis (IDA) is continuously developed and applied. IDA of fusion diagnostics is
the combination of various diagnostics in one concise formalism to improve physics knowledge and increase the reliability of results. For obtaining robust, validated physical
results IDA requires a systematic and formalized error
analysis of all (statistical and systematic) uncertainties
involved in each diagnostic. BPT allows systematic combination of all information entering the diagnostic model that
considers all uncertainties of measured data, calibration
measurements, physical model parameters, measurement
nuisance parameters, and the quality of the physical models.
Prior physics knowledge of model parameters and handling
of systematic errors is provided. A central goal of integration of redundant or complementary diagnostics is to remedy inconsistencies and reduce estimation uncertainties of
physical quantities by exploiting interdependencies. Fusion
diagnostics statistically modeled and under exploration for
IDA are Thomson scattering, ECE, bremsstrahlung spectroscopy and microwave interferometry (Cooperation with
A. Dinklage, E. Pasch, H. Dreier, W7-X, H. Meister,
B. Kurzan, ASDEX Upgrade).
These growth contributions for the various species are presented in figure 1 and compared with the film growth per pulse.
The growth contributions of CH3 and CH2 are negligible
over the whole investigated process parameter range. The
main growth precursor changes with Emean (= mean available
energy per source gas molecule): for Emean<10 eV growth is
mainly caused by CH; hydrocarbon ions contribute here
only about 10 %. In the range of 10 eV<Emean<100 eV
the contribution of C2H and C2H3 is dominant and only for
Emean>100 eV CxHy ions come to play an important role.
Furthermore, the dependence of the film properties on the
process parameters was investigated. The properties do not
depend solely on the energy of the impinging ions, but also
on the value of Emean. The film properties are determined by
the dissipated energy per incorporated carbon atom.
Experimental design of fusion diagnostics
It is of major concern for any scientist planning experiments
to optimize their design with respect to best performance
within expected experimental scenarios. The design of both,
the fusion diagnostics hardware and the running program, is
often essential for the success of the physics program of
future fusion devices. We introduced a probabilistic framework for quantified experimental design of fusion diagnostics and started to apply it to Thomson scattering and
microwave interferometry experiments. The goal is to maximize the utility of a future experiment with respect to hardware constraints and for best performance for expected
physics scenarios. A utility function to measure information
gain is given by the mutual information (Kullback-Leibler
distance) between the posterior and the prior distribution.
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Centre for Interdisciplinary Plasma Science
The information gain is measured in units of bits and correlated with estimation uncertainties of physical parameters of
interest such as Te and ne. The optimal design parameters of
the experiment are obtained by maximizing the expected
utility function, suitably marginalized over data and parameter space. Design parameters of future Thomson scattering
experiments are, e.g., the number, positions and widths of
spectral bands (Cooperation with A. Dinklage, E. Pasch,
H. Dreier, W7-X, B. Kurzan, ASDEX Upgrade).
requires considerable operator interaction which is not feasible for routine measurements at large fusion devices like
ITER. We developed a method for the evaluation of fringe
patterns based on BPT and neural networks, bridging the
gap from noisy speckle data to a denoised fringe pattern for
subsequent automated unwrapping.
Online evaluation of soft-X-ray diagnostics
The long-pulse operation (up to 30 minutes) of the fusion
experiment W7-X requires continuous monitoring of the
plasma. A multi-camera X-ray tomographic system with 400
viewing chords will be installed inside the vacuum vessel of
W7-X to obtain information about plasma dynamics with
very high time resolution. All presently available algorithms
are unable to solve the inverse problem of the 2-dimensional
reconstruction of the emission intensities fast enough for
monitoring. For this purpose a Bayesian Neural Network has
been developed and integrated into the framework of the
data processing system of W7-X. Special care is dedicated
to the error estimation of the Bayesian Neural Networks and
robustness with respect to sensor failures.
Single variable scans
Energy confinement data of W7-AS are analyzed in terms of
reduced variables which consist of dimensionless combinations of the machine variables. The goal is to predict the single variable behavior from a data set with entries which differ in more than one variable setting from each other.
Bayesian neural networks are used to model the hyper-surface evolving for the energy confinement as a function of
the reduced variables. In order to tell which neural net is best
and to provide expectation values the multi-dimensional
multi-modal marginalization evidence integrals are calculated employing a Monte Carlo method called perfect tempering. A sensible most probable model and a most probable
number of neural knots were identified. These first steps are
intended as proof of principle for the employed numerical
methods. We are using it in ongoing work to examine the
single variable response of fusion devices to be found in the
ITER L-mode data base.
Bremsstrahlung background estimation at Wendelstein 7-AS
and ASDEX Upgrade
Efforts on developing and applying a robust method to separate the bremsstrahlung background from line contributions
were continued. Bayesian mixture modeling was applied to
automatically estimate the bremsstrahlung background
measured by the ZEB and CXRS diagnostics at ASDEX
Upgrade and by the UV-NIR spectrometer at Wendelstein
7-AS. Each measured data point is classified with a probability of consisting of bremsstrahlung only or if line emission contributes. The robust technique does not need censored data where data points have to be excluded. The code
was adapted for routine use in ASDEX Upgrade (cooperation with R. König and M. Krychowiak from W7-AS/X and
H. Meister from ASDEX Upgrade).
Neural networks
Neural Networks are a very powerful tool for parameter-free
estimation if there is only sparse information about a system
(i.e. very complex systems). The large number of degrees of
freedom (DOF) usually used for those networks implies a
tendency for overfitting of the data. Bayesian treatment of
neural networks based on hyperplane priors has proven to be
a successful approach to solve this problem.
Comparison of MCMC techniques
The increasing complexity of problems tackled with BPT or
other statistical methods enforces the use of Markov Chain
Monte Carlo (MCMC) techniques. Several recently suggested MCMC variants (e.g. Perfect Tempering, Hilbert curve
MCMC, Nested sampling) are promising candidates for
effective computation of the evidence, an indispensable
quantity for model comparison. A comparison of the different MCMC methods with respect to accuracy, robustness
and speed was started.
Speckle interferometry
In fusion devices plasma-wall interaction causes erosion and
redeposition. Determination of erosion depths is of high
importance since erosion limits the lifetime of plasma facing materials and eroded particles from the wall contaminate
the plasma, increase radiation losses and, therefore, degrade
the performance of fusion devices. An in-situ technique for
the detection of surface changes with µm-resolution is a necessary prerequisite to study the influence of different plasma
regimes on the plasma-wall interactions. Furthermore, the
large amount of data requires an automated data evaluation.
Speckle interferometry has already shown its potential for
erosion and redeposition measurements in fusion experiments. However, the automated reconstruction of phase
maps and erosion profiles from noisy speckle data still
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Centre for Interdisciplinary Plasma Science
Tokamak Turbulence Studies
Source detection and background estimation on ROSAT AllSky Survey data
BPT was continually applied to separate celestial sources
and background intensity on ROSAT All-Sky Survey x-ray
photon distributions. The coexistence of background and
sources is described with a probabilistic two-component
mixture model where one component describes background
contribution only and the other component describes background plus signal. A background map for the complete
field data of the ROSAT PSPC (0.1-2.4 keV) in survey
mode is processed simultaneously with a probability map
for having source intensities in pixel cells or domains. Each
pixel cell (or domain) is characterized by the probability of
belonging to one of the two mixture components. The mixture model technique allows one to consider all pixels for
the background spline estimation even those containing
additional source contribution. By correlating neighboring
pixels the detection sensitivity for weak and extended
sources was enhanced. The probabilistic method allows for
improved detection of faint extended celestial sources compared to the Standard Analysis Software System (SASS)
used for the generation of the ROSAT All-Sky Survey
(RASS) catalogues (cooperation with W. Voges and
G. Boese from MPE).
First principles flux tube free energy functional
A generalized first principles free energy functional has
been derived for local (or flux tube) kinetic and fluid computer turbulence simulations, which is exactly conserved by
the turbulence evolution equations except for collisions.
Since the functional has been derived independent of the
model turbulence equations, it can be used for a consistency
check for the turbulence model equations.
Computational zonal flow studies (with K. Itoh, NIFS, Toki,
Japan)
The growth rate of geodesic acoustic modes and zonal flows
(ZF) observed previously in edge and core turbulence computer studies has been investigated analytically. Moreover,
the phenomenological functional dependence of the Reynolds stress on the flow shear profile has been further studied in turbulence simulations for tokamak core parameters.
The flows show a preferred radial scale length, which
severely restricts the nonlinearities of the functional.
Pinch effect studies (with W. Dorland, University of Maryland,
USA)
Contrary to common wisdom, the residual particle transport
in ITG and TEM turbulence is controlled to considerable
extent by the passing electrons. Detailed numerical analysis
has shown this to be caused by a resonant electron component of the modes, which has surprisingly long parallel
extent. These giant electron tails dominate the modes, while
the ion contributions can be regarded as a small perturbation
controlling the particle flux. Thus, regarding the particle
transport, electrons and ions have changed roles compared
to the classical treatment of particle transport in ion-mixing
type modes.
Interdisciplinary work
Cell migration plays a key role in many medical questions,
as for example during wound healing and the transmigration
of leukocytes or tumor cells. The experimental time series
from phase contrast microscopy of cells moving on a 2D
substrate were analyzed and the long term propagation of
migrating cells was calculated.The identification of changes
in observational data relating to the climate change hypothesis remains a topic of paramount importance. Blossom time
series of sweet cherries were analyzed to study the functional behavior and calculate the rates of change in terms of days
per year.
The rheology of snow is still not well understood, though
many empirical and theoretical attempts have been made to
describe the gliding behavior of avalanche-like flows. In collaboration with the Eidgenössischen Institut für Lawinenforschung data obtained from mesoscale chute flows of
snow were analyzed to test the empirical constitutive law of
Bingham against more complex descriptions of flow behavior.
Scientific Staff
M. Bauer, T. Dürbeck, R. Fischer, S. Gori, F. Guglielmetti,
K. Hallatschek, C. Hopf, W. Jacob, H. Kang, B. Plöckl,
K. Polozhiy, R. Preuss, M. Schlüter, T. Schwarz-Selinger,
S. Chao, U. von Toussaint.
MaxEnt04
The Data Analysis Group of the Section Oberflächenphysik
organized the twenty-fourth international workshop on
“Bayesian Inference and Maximum Entropy Methods in
Science and Engineering” (MaxEnt04), July 25th-30th 2004,
in the IPP Garching. The conference was attended by about
100 scientists from 21 countries.
88
VINETA
Head: Prof. Dr. Thomas Klinger
Device and Operational
Parameters
The linear plasma device VINETA is operated
with a high-density low-temperature plasma in
order to investigate plasma waves and instabilities. The focus of research in 2004 was the
installation and characterization of an electron
cyclotron discharge in combination with the
helicon discharge to obtain control over the
plasma collisionality. Additionally, research on
drift wave was extended from single coherent
modes to the turbulence regime.
(i) low averaged ionization
degree (≤10 %) and
(ii) low electron temperatures
(3 eV) resulting in highly
collisional plasmas.
Recently, a new operational regime on VINETA was discovered by introducing magnetic
field gradients in the helicon
source regions. In this operation the neutral gas pressure
can be reduced by almost one
order of magnitude thereby reducing significantly the collision frequencies with neutrals. Figure 2 shows the measurement of plasma density and electron temperature for the
case of strong magnetic field gradient in the helicon source
region in the radial-axial plane. The predominant electron
heating occurs directly in the source region while the plasma
density increases downstream, supposedly by ionization due
to electrons accelerated in the self-consistent electric field at
the magnetic field gradient region.
The highly flexible linearly
magnetized VINETA device,
schematically shown in figure 1,
provides a broad operational
regime. The modular conceptional design allows shaping of
the magnetic field structure
from homogenous magnetic
field (B≤0.1 T with less than
1 % spatial ripple) to the production of localized or global
magnetic field gradients.
Electron Cyclotron Resonance Heating
The control over the Coulomb collisionality is essential for
the study of wave and instability phenomena in VINETA. To
obtain control over the electron temperature an ECR heating
system in addition to the helicon plasma heating has been
installed. The ECR system contains of a magnetron microwave source (2.45 GHz, 10 kW) and an antenna setup,
which radiates right-handed polarized waves parallel to the
ambient magnetic field. The magnetic field of one module is
specifically shaped to produce localized magnetic field gradients for resonant absorption of the R-wave.
The combined operation of a helicon discharge with ECR
heating provides the high-density plasma at much higher
electron temperature. Figure 3 shows the dependence of the
electron temperature, as measured by Langmuir probes, on
microwave power. Above a power threshold of 4 kW the
electron temperature raises and reaches 12 eV at moderate
powers of approx. 6 kW. The achieved values for plasma
densities and electron temperatures are in good agreement
with power balance calculations performed for VINETA.
The variation of the electron temperature allows for a control over the Coulomb collision frequency, which can be
reduced by three orders of magnitude.
Figure 1: Schematic drawing of VINETA. Also main diagnosics like the tunable microwave interferometer and two azimuthal probe positioning systems are shown.
Figure 2: Langmuir probe measurements of plasma density and electron
temperature in the radial-axial plane including the helicon source region.
Drift Waves
The primary plasma heating is non-resonant by helicon
waves in the frequency range of 10-30 MHz. At only a few
kW of input power high plasma densities up to 1019 m-3 are
achieved. However, a characteristic of helicon discharges is
that such high densities are obtained at
Drift wave can be destabilized in VINETA in a controlled
way by the ambient magnetic field strength. Single coherent
modes with mode numbers ranging from m=2-8 as well as
weakly developed turbulent regimes can be studied. One
focus of research was the clear identification of fluctuations
as drift waves and the influence of collisionality profiles on
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VINETA
Figure 3: Results of Langmuir probe evaluation for the electron tempera-
Figure 4: Color-coded correlation amplitude of density fluctuations in the
ture in the plasma center using two probes separated by approx. 1m along
the magnetic field. Above 4 kW a steep increase of the electron temperature
is observed.
azimuthal cross section. A large-scale fluctuation structure is clearly
observed.
Scientific Staff
the dispersion and mode structure. It was shown that single
coherent modes have a finite parallel wavelength, which is
predominantly determined by the axial boundary conditions
and clearly distinguishes the observed instability from flute
modes. The azimuthal mode structure shows a spiral shape.
This behavior was shown to be a direct result of the strong
radial gradients in collisionality, affecting the parallel electron response and thereby the phase velocity of the drift
wave.
The drift wave investigations have been extended to the turbulent regime. Here, the research focus is the formation and
propagation of turbulent spatiotemporal fluctuation structures. Newly developed probe arrays covering the entire
azimuthal plasma cross section are used to identify fluctuation structures and to characterize their propagation properties. This diagnostic setup allows for imaging of turbulent
fluctuations in real time. Figure 4 shows the result of correlation analysis of turbulent density fluctuations in the
azimuthal cross section.
The observed structures are of large spatial extent (approx.
3ρS). The correlation analysis also yields the temporal evolution of structures. After formation the propagation is primarily in azimuthal direction with background ExB drift.
Typically lifetimes of structures are on the order of 250 µs,
which is longer than typical eddy turnover times and characterizes coherent structures. The investigation of the propagation properties of turbulent structures is work in progress.
Radial components of propagation and phase relations
between turbulent structures in plasma density and potential
are of particular interest in the context of intermittent transport associated with such structures.
C. Brandt, O. Grulke, T. Klinger, A. Stark, T. Windisch,
A. Vogelsang, J. Zalach
90
Electron Spectroscopy
Head: Dr. Uwe Hergenhahn
Introduction
A novel autoionization process in weakly bonded, singly charged systems, Interatomic Coulombic Decay, has recently been demonstrated
by our group. We have now found evidence for
a related phenomenon in the autoionization of
neutral, valence excited Ne clusters. A new setup that allows rapid switching between the two
types of circular polarization enabled us to sensitively measure intensity differences in photoelectron spectra of chiral molecules.
Resonant ICD in Ne clusters
By tuning the excitation energy
below the ionization threshold
of an inner valence state, at
some energies this inner valence electron will be excited to
a discrete bound state. In isolated atoms and molecules, an
Auger-like autoionization of
these highly excited neutral
states is often found, and is
known as resonant Auger decay.
One can speculate whether in a cluster the positive hole may
relax by transmitting its energy to a neighbouring atom and
thus causing an autoionization from this site. By analogy,
this could be called a resonant ICD process.
We have therefore carried out an experiment to search for
ICD-like electrons below the Ne 2s threshold in Ne clusters,
and to determine whether their yield function reflects the
sub threshold resonances of the 2s shell. Photoelectron spectra at photon energies from 37-52 eV were recorded, which
bridge the 2s threshold at 48.04 eV for bulk and at 48.23 eV
for surface atoms in Ne clusters (figure 1).
Electron spectroscopy is an
important diagnostic tool for
the investigation of materials.
The electron spectroscopy group
currently uses the short wave
radiation produced at a synchrotron radiation source for
fundamental investigations on
photon matter interactions and
for the development of advanced equipment for electron spectroscopy. Experiments are
carried out at BESSY (Berliner Elektronenspeicherring für
Synchrotronstrahlung).
Photoionization of free clusters
The power of electron spectroscopy to investigate the electronic structure of matter has rarely been applied to clusters,
which due to their weak bonding may show new phenomena
observed neither in isolated atoms and molecules nor in bulk
matter. Within the last years, we have constructed a cluster
source which can be combined with a high resolution electron spectrometer for synchrotron radiation experiments. In
2003, with this apparatus we have given the first experimental demonstration of Interatomic Coulombic Decay (ICD), a
novel autoionization process, by which inner valence holes
can relax into a delocalized two-hole state under active participation of their chemical environment. ICD was originally
found in medium sized Ne and NeAr clusters.
In 2004, more detailed knowledge on the ICD process in Ne
was obtained by two follow-up investigations in cooperation
with other groups. Together with the group of Reinhold
Dörner (University of Frankfurt), we have investigated ICD
in the Ne dimer. In an ion-ion-electron coincidence experiment, the ICD electron was detected in coincidence with the
two singly charged Ne cations being the final state of the
decay. Theoretical predictions of much greater detail were
available for this small system than for larger clusters. The
experimental results were found to agree remarkably well
with theory. Since ICD is an ultrafast process, it should lead
to a lifetime broadening of the photoelectron lines from
inner valence states. In collaboration with the group of Olle
Björneholm (Uppsala University) we have carried out a high
resolution measurement of the 2s photolines from large Ne
clusters. It was possible to disentangle the lifetime broadening from other broadening factors, such as the cluster size
distribution. For electrons from bulk sites, a lifetime of
6±1 fs was determined. For electrons from surface sites, the
lifetime is larger due to the smaller number of nearest neighbours, but still in the fs range. Again, these results agree well
with theoretical predictions.
Figure 1: Low kinetic energy electron spectra of Ne clusters excited with
photon energies around the Ne 2s threshold. Resonantly enhanced, ICDlike features can be identified at two photon energies below the 2s threshold. Moreover, two lines related to inelastic energy loss of 2p photoelectrons by intracluster creation of excitonic states can be seen at all photon
energies.
Figure 1 clearly shows ICD-like spectral features at 47.1 and
47.5 eV photon energy. Comparing these results to published work on the 2s excitations in cryogenically condensed
Ne, we assign them to the surface and bulk components of
the 2s→3p Rydberg excitation, observed at 46.9 and
46.4 eV in the solid. Since the kinetic energy of electrons
from ICD of the 2s state above threshold is around 1.2 eV, it
seems evident that the electrons observed below threshold
result from resonant ICD-like processes of the type
91
Electron Spectroscopy
NeN + hν → Ne(2 s −1 3 p ) NeN −1 → Ne(2 p −1 3 p ) Ne(2, p −1 ) NeN − 2
which create electrons of somewhat higher energy due to
better shielding of one of the final state holes.
Cluster photoionization satellites
Quite generally, the photoionization lines due to single electron interaction are associated with weaker satellite lines as
a consequence of multi-electron processes. A wealth of
information has been gathered about satellite lines in atoms,
but apart from a recent work on excitonic satellites in Ne
and Ar clusters by our group, to the best of our knowledge
no studies of photoionization satellites in clusters have been
reported. We have observed the lowest binding energy 2p
correlation satellite of Ne (atomic final state configuration
2p4(1D)3s), emitted from Ne clusters. With the onset of cluster formation, the appearance of a satellite component at
somewhat lower binding energy then the monomer contribution can be observed, which is in exact analogy to the main
line. Contrary to the valence main lines, however no splitting of the satellite line into bulk and surface component
occurs, although we can show that probably both bulk and
surface sites contribute. This unexpected behaviour currently still awaits explanation.
Figure 2: Asymmetry of the photoelectron intensity from the carbonyl C 1s
orbital of carvone together with data of a multiple scattering calculation.
Measured data were normalized by a factor of cos (54.7°), which arises
from the geometry of our experiment. For R-carvone, the calculation would
yield the mirror image with respect to the zeroline of the curve for
S-carvone.
The size of the error bars shows that in two beam mode
apparatus asymmetries of well below 0.01 can be achieved.
This is a substantial increase in sensitivity compared to earlier experiments. Apart from these technical aspects the figure shows that photoelectron circular dichroism is an effect
the relative size of which by far exceeds the dichroism in
absorption of visible light, which is conventionally used to
derive information on a handed sample.
Photoelectron Circular Dichroism in chiral molecules
Modern synchrotron radiation sources can produce circularly polarized light in the UV and X-ray wavelength range.
Using this a new dichroic effect, photoelectron circular
dichroism, has recently been found by our group and independently by other researchers. This effect manifests itself
as a difference in the angle- and energy-resolved photoelectron yield of an unordered sample of chiral molecules. A
normalized intensity difference (“asymmetry”) of 5 % and
larger was found. In earlier experiments however the control
and correction of apparatus contributions to the asymmetry
was a serious problem. In cooperation with the group of
Ivan Powis (University of Nottingham) we are aiming at
methods to detect photoelectron circular dichroism more
reliably. For the past two years, a new operation mode of the
MPG beamline at BESSY has been available, which allows
for a quick (0.1 Hz) alteration between the two types of circular polarization by a mechanical chopper. Results obtained with this so-called two beam mode in 2004 are shown
in figure 2.
Scientific Staff
Silko Barth, Sanjeev Joshi, Volker Ulrich, Simon Marburger,
Alex M. Bradshaw, Uwe Hergenhahn.
The figure shows the difference in the photoelectron intensity of the carbonyl C 1s line of carvone normalized to the
total signal intensity. For these experiments, the electron
spectrometer was placed to accept electrons emitted downward under an angle of 54.7° with respect to the propagation
direction of the circularly polarized synchrotron radiation.
92
Infrastructure
Computer Center Garching
Head: Dipl.-Inf. Stefan Heinzel
Introduction
For the IBM supercomputer with a peak performance of 5.2 TFlop/s, application support
was given in plasma physics, materials science,
astrophysics and biophysics. The data acquisition system for Wendelstein 7-X was further
developed to support first laboratory equipment. For analyses of genomic sequences and
proteins a workflow engine was built which
was awarded the 1st prize of the “Heinz Billing
Award” 2004. EU project DEISA has started
with significant RZG participation.
European Infrastructure for
Supercomputer Applications).
RZG hosts the cell “deisa.org”.
Long time conservation for
newly added valuable data
(digitalized photo archives,
sound and video documents)
are also stored in MR-AFS. Six
new AFS-fileservers have been
integrated for the projects
Magic and ATLAS on behalf of
the MPI for Physics. The total
net data volume in the cell
“ipp-garching.mpg.de” has crossed the 50 terabyte line.
Rechenzentrum Garching (RZG)
traditionally provides supercomputing power and archival services for IPP and other Max Planck
Institutes throughout Germany.
Besides operation of the systems,
application support is given to
Max Planck Institutes with highend computing needs in fusion
research, materials science, astrophysics, and other fields. Large
amounts of experimental data from the fusion devices of IPP
(ASDEX Upgrade, formerly Wendelstein 7-AS, and, later,
Wendelstein 7-X), satellite data of MPI of Extraterrestrial
Physics (MPE) at the Garching site, and data from supercomputer simulations are administered and stored with high lifetimes. In addition, RZG provides network and standard services
for IPP and part of the other MPIs at the Garching site. The experimental data acquisition software development group for the
new Wendelstein 7-X fusion experiment and the current
ASDEX Upgrade fusion experiment operates as part of RZG.
Archival and Backup System
To decrease costs two of the three StorageTek silos have
been put out of maintenance and their data are being transferred to the third one which was equipped with the new
high density 9940B tape drives. This temporary solution
now concentrates the archives in a single room
Developments for High End Computing
Major Hardware Changes
High-performance computing is a key technology for IPP
and other Max Planck Institutes. Application development
and support for high-end parallel computing is of great
importance for disciplines especially in the fields of plasma
physics, materials science, and astrophysics. Projects to support new developments in close collaboration with the
respective scientists are described in detail.
The IBM pSeries 690 based supercomputer was expanded to
a peak performance of 5.2 TFlop/s and 2.25 TB of main
memory, by adding further nodes up to a total number of 32
with integration into the IBM High Performance Switch
(HPS, “Federation Switch”). For non-parallel vectorizing
codes, a NEC SX-5 vector system with 3 processors and 12
GB of main memory was available with high single processor performance. As general or dedicated compute servers,
rack-based Linux systems with Intel Xeon processors have
become very popular. The number of installed and operated
systems at RZG has further strongly increased in 2004. Such
institute or department servers have been operated and
maintained for: IPP, Fritz-Haber-Institute, MPI for
Astrophysics, MPI for Polymer Research, MPI for Quantum
Optics, MPI of Developmental Biology, MPI of Extraterrestrial Physics, MPI for Biochemistry, MPI for Chemical
Physics of Solids, MPI for Physics. The peak aggregated
performance of the linux clusters exceeds 2 TFlop/s.
Fusion Research
EUTERPE and GYGLES Code
The close support for the Stellarator Theory Division has
been continued on the subject of gyrokinetic particle-in-cell
(PIC) simulations. The enhancement of the three-dimensional EUTERPE code to W7-X geometry came to a level
where the results of linear ion temperature gradient driven
mode (ITG) simulations could be presented to the scientific
community. Hence the collaboration has been concentrated
on the GYGLES code with the focus on a further development of electromagnetic PIC algorithms. This effort which
started already last year could show that reliable PIC simulations with todays computer resources are possible in the
magneto-hydro-dynamic (MHD) limit. The efficiency of the
algorithms could be increased dramatically. The applied
control variates Monte-Carlo method resulted in a speed-up
of a factor 1000 in case of the MHD limit for W7-X relevant
parameters. It seems to be possible now to perform such
simulations with a reasonable computational effort. Thus a
more realistic numerical simulation of fusion plasmas starting from first principles seems to be feasible. This progress
Data Management
Multiple-resident AFS and OpenAFS
User home directories are stored on mirrored RAID systems on two fileservers which can replace one another. So
high availability is achieved even in the case of a server or
RAID system being lost. OpenAFS is being used as one of
the global shared file systems for DEISA (Distributed
95
Computer Center Garching
in the field of numerical algorithms has been presented to
the scientific community by an invited talk at the Joint
Varenna-Lausanne International Workshop.
called Millenium Run. Main memory reserved for system
tasks per node was further minimized in order to allow for a
maximum memory usage per node for user (application)
space.
GENE Code
The GENE turbulence code (of the Tokamak Theory
Division) has been supported in two ways. First; GENE was
ported to a Linux environment. This allows the usage of
cheaper Linux clusters as development platforms with the
advantage of very efficient compile times and the availability of different compilers for error diagnostics. Inclusion of
the hardware optimized Intel Math Kernel Library (MKL)
led to a significant performance increase. With the algorithmic modification of the usage of the reversed triangular factorization the compact finite difference scheme can be performed with fewer operations. Second, with further
functionality enhancements by the authors, a new scalabity
bottleneck was introduced with a new routine. This bottleneck was detected, analysed and identified and suggestions
were given for improvements.
Life Sciences
PHASE
The program package PHASE from Washington University
for the reconstruction of haplotypes from population-genotype data based on a Bayesian statistics method was ported
to and optimized for both Linux and AIX systems, to support a project from MPI for evolutionary Anthropology, dep
Paabo. A wrapper program was written (in a combination of
MPI and C++) that allows for high throughput processing of
thousands of files both on the IBM Regatta system and on
Linux clusters. Additionally so-called job-arrays were configured for the SUN Grid Engine batch system used on the
Linux clusters at RZG.
Gromacs
For the classical molecular dynamics code package GROMACS support was given for MPI for biophysical
Chemistry, dep Grubmueller. The goal was to significantly
improve the scalabity behaviour of the parallel code. The
authors have been visited in Sweden and options for GROMACS optimization have been discussed in detail. A strategy was developed and three work packages were defined.
These essential parts are: 1. optimization of the PME part
(Particle Mesh Ewald method), 2. separation of PME and PP
(particle-particle interactions) parts, and 3. introduction of
dynamic load balancing in the PP part. PME optimization
could already be realized by RZG which led to an overall
performance increase of 50 % for the user selected problem.
On a 32 way IBM Regatta node the original speedup of 14
could be increased to 21.
TRIM.sp Code
A special variant of the TRIM.sp sputtering code (for tracing
of selected trajectories) has been ported to Linux. Therefore
the code, lately still equipped with Cray proprietary onesided communication scheme (shem) for Cray T3E systems,
was also ported to standard two-sided MPI communication.
A new parallel random number generator was integrated.
Materials Sciences
WIEN2K Package
For small runs with a moderate number of processors (up to
16), the parallel program package WIEN2K, a quantum
mechanical code for the calculation of electron configurations in crystals from the Technical University of Vienna,
has been ported to a Linux cluster. Scalapack and MKL
library routines were included for a performance increase.
Bioinformatics
In an interdisciplinary cooperation with several MaxPlanck-Institutes RZG is establishing an integrated software
platform for bioinformatics tools and databases which is tailored to the research with microbial genomes. For this task
an additional scientific position has been provided by the
MPG. Besides hosting dedicated computing and storage
facilities for the consortium and providing user-support on
various levels, RZG contributes original software development to “MiGenAS” (Microbial Genome Analysis System).
The so-called MiGenAS workflow engine allows researchers to perform convenient and versatile web-based
analyses of genomic sequences and proteins. This piece of
software was awarded with the “Heinz Billing Award for the
Advancement of Scientific Computation”.
In the course of 2004 the system has been substantially
FHImd98 Code
A feasibility study was done about restructuring FHImd98
towards a so-called k parallel version which would allow
usage of low-cost Linux clusters for trivial parallel program
execution for independent k points. Since a major effort
would have been necessary and source code divergence
would have been the price it was recommended to stay with
the current (single source) version and use an adequate
interconnect (e.g. Myrinet, Infiniband) on a Linux cluster.
Astrophysics
Gadget
Support was given for usage of the cosmology simulation
code GADGET for usage on 512 processors and with a
requirement of nearly 1 TByte of main memory for the so96
Computer Center Garching
extended and was made available to all Max-Planck
researchers.
ting the need of limiting switches at workgroup or story
level. This structure drastically enhances overall network
performance, for all connections between centralized
switches are now at a speed of 1 Gigabit/s (Gigabit Ethernet
technology) with the option of implementing even more
powerful trunks. Due to the availability of both multi-mode
and mono-mode fibre optic cables between the premises it is
also possible to adopt upcoming new network technologies
such as 10 or 40-Gigabit Ethernet. With this structure we
also improved the security and integrity of data because
eavesdropping is almost impossible. For logical security
based on the functionality of the internet protocol suite
TCP/IP a packet filter firewall at the access point to the
internet is implemented, where all the incoming/outgoing
packets are checked against a set of blocking or granting
rules. Additionally all incoming electronic mail is scanned
for viruses and only clean and unobjectionable data (based
on known problems) will be passed to the internal network,
the rest gets quarantined. Spam mail filtering is also active.
Users can now individually define and set filter threshold
values. For the new building of the computer center further
complex reconfigurations are still necessary to converge the
physical and logical layers of the network.
Multimedia
Videoconferencing (VC)
The VC infrastructure was very stable, see the RZG
Gatekeeper (GK) statistics (graph). The GK was available
on 360 days, with 3 scheduled shut-downs and 5 short
breaks due to installation of new software. In 2005 the total
number of successful calls was ≈10.000, the proxy data
2 Terabyte. The number of registered endpoints reached 159:
IPP (40), MPG (15), HGF (4), EFDA (27) and others. The
first 30 Systems in the graph were in conferences for ≈1700
hours. 6 Systems from new EFDA associates – Czech
Republic, Estonia, Latvia, Slovakia, and Slovenjia were
added to the RZG-VC community. The RZG GK concept
was adapted by Latvia, Hungary and others. 30 % of all calls
have been user support. Regular multipoint conferences by
DEISA associates are assisted by RZGs video group and
have been run on the MCUs of the DFNVC.
Presentation sharing became more and more popular. IPPs
systems can use DuoVideo (also on a MCU lent from
Tandberg). The respective ITU standard H.239 was still
blocked by non-compatibilities between all major vendors.
The free software VNC is available for all RZG partners.
Data Acquisition and Data Bases for Plasma
Fusion Experiments
The main task of the XDV group at the computer center
Garching is the development of the data acquisition, archiving and processing system for W7-X. The design of this
system is strongly influenced by the design goals of the
experiment. On the contrary to the previous shot oriented
operation, the long pulses of W7-X require continuous sampling, archiving and displaying of collected data. A large
number of diagnostic systems will be implemented to investigate the behavior of the plasma. The amount of data, that
has to be handled, is some magnitudes higher and requires
new techniques for compression, archiving and retrieval. At
the end of 2003 we reached a major milestone in the development cycle of the system and demonstrated a sample
experiment with three different types of data acquisition systems to the future users and physicists. This successful
working system still contained some preliminary definitions
and implementations that had to be worked on. The complete design was reviewed and missing or not completely
defined structures have been identified and fixed. This
involved the acquisition software as well as the database
design. It is very important in the future that the database
structures will stabilize, since with any change in the structure, the configuration data and the archived measurement
data may be lost. With the advent of laboratory experiments,
diagnostic setup and heating prototypes, that all will use the
data acquisition system, this is not tolerable anymore. At the
Graphics Software
Five AMIRA graphics licenses have been purchased for
users from Stellarator-Theory and Tokamak-Physics.
Data Networking
IPP’s data network infrastructure was planned with a cabling
structure in mind that can easily be adapted to future technologies. The network realized is therefore based on the concept of a “collapsed backbone”, consisting of high-level
switches at a few central locations which directly connect to
all endpoints via links based on copper or fibre – elimina97
Computer Center Garching
beginning of 2004 the group, that is responsible for the control system of W7-X decided to use our database system
(Objectivity) for their configuration and segment data. The
control system will be based on a real time operating system
(VxWorks) with several distributed control stations. Since
there is no objectivity client available for VxWorks, we
designed together with the control group a portal based on
TCP/IP and a proxy server with access to the common database. The same portal is also used in the data acquisition stations to read the configuration data. This enables us now to
store configuration data and measurement data in different
federations. The control system configuration data is now
fully integrated with the configuration data of the data
acquisition system. The same is true for the segment definitions and experimental programs. We also started projects to
build data acquisition systems for laboratory experiments.
One system was used for measurement of heat loads and
radiation exposures on components near to the ECRH antenna in the vacuum vessel. A special vacuum chamber was
constructed and attached to the ECRH beam line of W7AS
in Garching. Any components or materials exposed to the
ECRH radiation in W7-X can be tested in this chamber. The
data acquisition system was built on National Instruments
Components consisting of a Compact PCI crate with a NI
CPU running Windows XP operation system. Data acquisition is done by a NI 6052E ADC in combination with SCXI
modules for thermocouple measurement and high/low passes filter inputs. In the future a compact PCI video camera
controller will be available. The video system will be used
for visual inspection of the components and to document
any damage. At the moment a second data acquisition system is tested for the first Gyrotron of the ECRH system at
W7-X. It consists of two different components. One module
is used for slow measurement of continuous surveillance
data. For this task we use an Adlink 2205 ADC with 64
channels and a maximum sample rate of 500 KHz for all
channels together. This continuous data is also available for
monitoring purposes. Three additional modules are used for
triggered fast measurement. Data is continuously stored in a
cyclic buffer and if an important external event like a
flashover occurs, data acquisition is stopped and data is
transferred to the archive for later inspection. For this purpose we use an Adlink 2010 ADC with 4 Channels and a
sample rate of 2 MHz. Both type of modules are Compact
PCI boards and are handled by a PC running the Red Hat
Linux operation system. The implementation of the configuration and segment editor for the Objectivity database was
finally started. This tool is very important for the usability
and acceptance of the whole system, since all configuration
data and segment definitions will be handled by this editor.
It is used for the setup of the control system as well as the
setup of the data acquisition stations and has to guide the
user through the data structures of the database. After login
every user defines a set of workspaces that contain an arbitrary collection of objects from the database. These objects
can be displayed, edited, copied and compared to other
objects. This workspace concept reduces the view on objects
to a manageable subset for the user. A first version of this
editor (CONFIX) was available by the end of 2004.
The DEISA Project
In May 2004 an FP6 EU Integrated Infrastructure Initiative
(I3) Project called DEISA has started. DEISA stands for
Distributed European Infrastructure for Supercomputing
Applications (see www.deisa.org). Goal of the project is
the advancement of computational sciences in supercomputing in Europe. Major supercomputer centres are coordinating their actions to jointly deploy and operate a distributed
terascale supercomputer infrastructure. As a first step
DEISA will be constituted from four homogeneous platforms at CINECA (Bologna, Italy), FZJ (Juelich, Germany),
IDRIS (Orsay, France) and RZG (Garching, Germany).
RZG belongs to the initiators of the project. Later platforms
from CSC (Espoo, Finland), ECMWF (Reading, UK),
EPCC (Edinburgh, UK), SARA (Amsterdam, NL), BSC
(Barcelona), HLRS (Stuttgart, Germany) and LRZ (Munich,
Germany) will be integrated. Service activities are carried
out to integrate leading grid technologies. Joint research
activities shall support the inclusion of leading applications
in computational sciences and the involvement of leading
computational scientists in Europe. A virtual private network connection has been realized through GEANT, with
national access via NRENs, on the basis of premium IP
services and priority routing. Initially a 1 Gb/s connection
per connected site was realized. Extension to 10 Gb/s will
occur in phase with the GÉANT upgrade in 2005/2006.
RZG is task leading one service activity (data management
with global file systems) and two joint research activities
(for plasma physics and materials science).
Staff
A. Altbauer, G. Bacmeister, A. Baragatti**, V. Bludov,
K. Desinger, R. Dohmen, R. Eisert*, I. Fischer, S. Gross,
A. Hackl, C. Hanke, R. Hatzky, S. Heinzel, C. Hennig*,
H. Kroiss, G. Kühner*, H. Kühntopf*, K. Lehnberger,
H. Lederer, H. Maier, R. Mühlberger, K. Näckel*, W. Nagel,
M. Panea-Doblado, P. Pflüger, F. Pirker,A. PorterSborowski, M. Rampp, J. Reetz, H. Reuter, S. Sagawe*,
H.-G. Schätzko, R. Schmid, A. Schott, H. Schürmann*,
J. Schuster, T. Soddemann, H. Soenke, U. Schwenn,
K. Stöckigt, R. Tisma,S. Valet*, Th. v. Weber*, I. Weidl.
Data Acquisition Group: P. Heimann, J. Maier, M. Zilker
*IPP Greifswald, **since September 2004
98
University Contributions to
IPP Programme
University of Augsburg
Lehrstuhl für Experimentelle Plasmaphysik
Head: Prof. Dr. Kurt Behringer
Plasma Wall Interaction
In collaboration with the “Experimental Plasma
Physics Division E4” the research is focused on
diagnostics of low temperature plasmas including fusion edge plasmas. Main emphasis is
given to the development and application of
diagnostic methods which are verified in several low pressure plasma experiments (ECR, MW
and RF plasmas) and are supported by modelling of plasma parameters.
C2 emission (Swan band around
516 nm) with C2Hy (y=2,4,6)
particle densities (fluxes).
Since the CH emission (Gerö
band around 431 nm) is correlated with CH4 particle densities (fluxes) the intensity ratio
C2 Swan / CH Gerö is related to
the C2Hy/CH4 particle ratio as
shown in figure 2. In the case
of CH4 an intensity ratio of typically 0.1 is observed independent of the isotope (H or D)
and the background plasma (He, H, D). Here, methane dominates whereas the higher hydrocarbons and thus C2 particles
are produced in a secondary step resulting in weak C2 emission. The situation is reversed in case of the C2 family
(C2H2, C2H4, C2H6). As a consequence, the intensity ratio is
a factor of ten increased in both types of discharges. In the
ECR plasma the spectroscopic measurements are verified by
measurements with a residual gas analyser and particle
modelling. Thus, it is recommended to use the intensity ratio
as a monitor for the C2Hy/CH4 particle ratio. On the basis of
these measurements a simplified formula for the analysis of
measurements of erosion yields is developed which now
takes into account the formation of higher hydrocarbons
(C2 group) in the chemical erosion process.
Chemical Erosion
The chemical erosion of pyrolytic graphite and several doped
carbon materials has been investigated in low pressure hydrogen plasmas (ICP discharges). From time resolved measurements of the intensities of
CH (CD) and C2 molecular
bands, which are calibrated by weight loss measurements,
fluence dependent erosion yields are obtained. In co-operation with the Material Research group at IPP, the identical
materials are investigated in ion beam experiments. Figure 1
shows the results for pyrolytic graphite and for TiC doped
graphite (4 % TiC/C) at a probe temperature of 300 K and
ion energy of 30 eV. As expected, the erosion yield of pure
graphite is independent of the fluence, whereas the erosion
yield of the doped material decreases with time due to the
enrichment of dopants on the surface. The relative dependence is similar in both experiments, however the absolute
values differ. Higher values are obtained in the plasma
experiment (ICP) due to a simultaneous bombardment of the
surface with hydrogen ions and atomic hydrogen where
chemical sputtering takes place. From a comparison with the
ion beam experiment an enhancement factor of 1.7 (flux
ratio atoms/ions=220) could be determined.
Modelling of Particle Densities
A flexible solver for modelling of particle densities in plasmas is developed in the framework of a doctoral thesis. The
model Yacora can be used for collisional radiative (CR) modelling as well as for dissociative modelling with the aim to
Figure 1: Comparison of fluence dependent erosion yields of pyrolytic
graphite and TiC doped graphite obtained in ion beam experiments and in
ICP discharges.
Diagnostics of Hydrocarbons
Systematic investigations of the spectroscopic diagnostics of
hydrocarbons have been carried out in ECR discharges and
were then applied to the divertor plasma of ASDEX
Upgrade. Emphasis has been laid on a correlation of the
Figure 2: Measured intensity ratios (C2/CH molecular band emission)in
ECR discharges with admixtures of different hydrocarbons to helium and in
H, D and He discharges of ASDEX Upgrade during gas puffing of hydrocarbons in the outer divertor
101
University of Augsburg
tion. Since the plasma is well diagnosed atomic and molecular density as well as ne and Te are known and used in the calculations (filled triangles). An increase in Te of 0.5 eV requires
a decrease of ne to match the absolute values (open triangles)
being then outside the error bars of the measurements. In the
recombining plasma Balmer lines up to quantum number 20
are easily observed. Here, H2+ and H+ are the dominant
species in populating the H atom. They are successfully obtained from a fit of the calculation to the measurements
using the known parameters ne and Te. To demonstrate the
sensitivity of the method n(H2+) and n(H+) are varied by a
factor of ten in each direction. It is obvious that H+ populates predominantly the higher quantum numbers whereas
H2+ enhances the population of the low quantum numbers.
Thus, from shape and absolute values of Balmer line radiation the two densities can be obtained with high accuracy
representing a simple diagnostic tool for ion particle densities.
Publications and Lectures
U. Fantz, Emission Spectroscopy of Molecular Low Pressure Plasmas, Contrib. Plasma Phys. 44 (2004) 508.
U. Fantz, Optical Phenomena in the Open Air, Contemporary Physics 45 (2004) 93.
U. Fantz, D. Wünderlich, Franck-Condon Factors, Transition
Probabilities and Radiative Lifetimes for Hydrogen
Molecules and Their Isotopomeres, IAEA Report,
INDC(NDS)-457 (2004).
P. Starke, U. Fantz, M. Balden, Systematic Investigations of
Carbon Materials in Hydrogen and Deuterium Low Pressure
Plasmas, PSI-16 Portland Maine, USA, 2004.
U. Fantz, S. Meir and ASDEX Upgrade Team, Correlation
of the Intensity Ratio of C2/CH Molecular Bands with the
Flux Ratio of C2Hy/CH4 Particles, PSI-16 Portland Maine,
USA, 2004.
U. Fantz and NNBI group, Diagnostics of the Cesium
Amount in a RF Negative Ion Source and the Correlation
with the Extracted Current Density, SOFT Conference,
Venice, Italy, 2004.
U. Fantz, Basics of Plasma Spectroscopy, European Marie
Curie Training Course on “Low Temperature Plasma Physics:
Basics and Applications”, Bad Honnef, Germany, 2004.
P. Starke, Chemische Erosion verschiedener KohlenstoffMaterialien durch Wasserstoff-Isotope in Niederdruckplasmen, Dissertation, Universität Augsburg, 2004.
D. Wünderlich, Berechnung von Teilchendichten für die
Diagnostik an Niederdruckplasmen, Dissertation, Universität Augsburg, 2004.
Figure 3: Measurements and calculations of Balmer line emission in an
ionising plasma (ICP) and in a recombining plasma (PSI-2).
support and complete experimental diagnostic techniques.
The code is successfully applied to helium plasmas (CR
modelling) and plasmas with hydrocarbons (dissociation
modelling). However, the main effort is laid on hydrogen
plasmas, which need a combination of both. In continuation
of the last years, the CR model for hydrogen, in particular
molecular hydrogen, has been very much improved. Electronic states up to main quantum number three are now electronically resolved and spectroscopic relevant transitions are
even vibrationally resolved. For that purpose, a fundamental
data base of Franck-Condon factors, transition probabilities
and radiative lifetimes for the hydrogen molecule and its isotopomeres (D2, T2, HD, HT and DT) has been calculated and
published. The coupling of different particle species (H2, H,
H2+, H+, H−) offers the possibility to calculate their contribution to the Balmer line radiation which is of particular interest in spectroscopic diagnostics of ionising and recombining
plasmas as well as in negative ion sources. Applications to
negative ion sources are carried out in co-operation with the
NNBI group, Technology division at the IPP. Figure 3 shows
applications to an ionising plasma (inductively coupled discharge, ICP) and to a recombining plasma (PSI-2 generator,
in co-operation with the Plasma Diagnostics group, Humboldt University, Berlin). In the ionising plasma (ionisation
degree ≈10-4) only H2 and H contribute to Balmer line radia-
Scientific Staff
U. Fantz, P. Starke, D. Wünderlich, M. Berger, S. Meir,
S. Dietrich, M. Regler, S. Riegg, M. Drexel
102
University of Bayreuth
Lehrstuhl für Experimentalphysik III
Head: Prof. Dr. Jürgen Küppers
Elementary reactions of hydrogen atoms with adsorbates and
solid surfaces
Cooperation between IPP and the University of
Bayreuth is concentrated on investigating fusion-relevant plasma-wall interaction processes.
Accordingly, the hydrogen atom surface chemistry on possible reactor wall materials is the
primary research topic.
the perspective view on a D
covered surface suggests the
existence of “high” and “low”
atoms, confirmed by an analysis along the lines A and B. The
height difference of these atoms
extracted from various scan
lines was obtained as 0.4 Å.
The coincidence with the theoretical puckering height is
assumed to be fortuitous, since the STM profile heights cannot directly be converted into length scales. Irrespective of
this, the STM data also confirm the theoretically predicted
puckering of C upon H bonding.
A considerable fraction of the
species impinging on the first
wall of a fusion experimental
vessel are neutrals and ions in
the energy range below a kinetic energy of about 10 eV.
These particles are not capable of causing physical sputtering, but can induce several processes, such as chemical erosion, abstraction etc, which contaminate the plasma. Since
low-energy ions are neutralised in the immediate vicinity of
a substrate by resonance neutralisation, it is sufficient to
study the low-energy atom-surface interaction. For experimental reasons, the present work utilised only thermal atoms
with energies in the range of a few tenth of an eV.
Despite the fact that impinging high energy ions from the
boundary plasma transform a considerable fraction of the
surfaces of carbon tiled walls into hydrogenated a-C:H, it is
of interest to know whether H atoms exhibit strong interaction with graphite surfaces. As reported in the IPP report of
the year 2002 and published recently, we demonstrated for
the first time that H adsorbs on the basal plane of graphite.
The experimental adsorption energy and parallel and normal
vibrational frequencies were in excellent agreement with
theoretical predictions based on DFT calculations. These
DFT calculations illustrate that adsorption of H on the
C(0001) surface is slightly activated and requires a local
reconstruction of the surface: the C atom on top of which the
H eventually gets bound must pucker out of the surface by
about 0.4 Å.
Experimentally, this prediction can be only confirmed using
techniques which deliver structural information on the very
first layer of a H covered C(0001) substrate, such as LEED
(low energy electron diffraction) and STM (scanning tunnelling microscopy). Diffraction requires translational symmetry on the surface – which is lifted by puckering of C
atoms – and therefore H covered C(0001) surfaces should
only display diffuse scattering in LEED (with the exception
of fully ordered H layers). LEED observations indeed
revealed only diffuse scattering. Likewise, in STM pictures
of C(0001) surfaces partially covered with H one should
observe unpuckered (low-placed) and puckered (highplaced) C atoms. The figure compares STM pictures of
clean (a) and D covered (b) HOPG surfaces. The perspective
view on a 25 Å x 25 Å section of a clean graphite surface
shown in figure 1a displays the expected hexagonal arrangement of C atoms since every second C atom is invisible to
the STM. Scans along the lines A and B confirm that the
atoms are equally “high”. In contrast, as shown in figure 1b,
Perspective STM images of 25 Å x 25 Å wide regions on graphite surfaces
(HOPG sample). a) clean C(0001) surface, b) D covered C(0001) surface.
On a priori stressed C(0001) planes puckering of C should
be difficult and H adsorption significantly reduced. In order
to investigate this, H adsorption on low-energy Ar ion bombarded graphite surfaces was studied. On these surfaces subplanted Ar lift the topmost plane and cause stress in the top
103
University of Bayreuth
surface plane. As expected, the H adsorption capacity was
observed to be reduced, but could be recovered after thermal
activation of Ar outgassing. Irreversible defects generated by
ion bombardment (C plane defects) caused a complete loss
of the capability of the C(0001) plane to adsorb H. Since
these defects cover the whole surface after application of ion
doses as small as a few 1015 cm-2 the favourable H adsorption properties of graphite are not relevant for applications
in fusion devices.
Conference contributions
T. Zecho, A. Güttler, and J. Küppers
Reactions of thermal D with graphite (0001) surfaces:
hydrogenation and etching of basal plane edges.
Annual APS March Meeting 2004, Montreal, Canada,
March 22-26, 2004
A. Güttler, T. Zecho, and J. Küppers
Adsorption of thermak D (H) atoms on Ar ion bombarded
(0001) graphite surfaces.
Annual APS March Meeting 2004, Montreal, Canada,
March 22-26, 2004
Publications
D. Kolovos-Vellianitis and J. Küppers
Abstraction of D on Ag(100) and Ag(111) surfaces by
gaseous H atoms. The role of electron-hole excitations in hot
atom reactions and the transition to Eley-Rideal kinetics.
Surf. Sci. 548 (2004) 67
A. Baurichter, L. Hornekaer, V.V. Petrunin, A. C. Luntz,
S. Baouche, T. Zecho, J. Küppers
The dynamics of associative desorption of chemisorbed D
atoms on graphite(0001).
Annual APS March Meeting 2004, Montreal, Canada,
March 22-26, 2004
A. Güttler, T. Zecho, and J. Küppers
Interaction of H (D) atoms with surfaces of glassy carbon:
adsorption, abstraction, and etching.
Carbon 42 (2004) 337
S. Baouche, L. Hornekaer, V.V. Petrunin, A.C. Luntz,
T. Zecho, J. Küppers , A. Baurichter
The dynamics of associative desorption of chemisorbed
deuterium atoms on graphite (0001).
Danish Physical Society Annual Meeting, Nyborg,
Denmark, 27-28 May 2004
T. Zecho, A. Güttler, and J. Küppers
A TDS study of D adsorption on terraces and terrace edges
of graphite (0001) surfaces.
Carbon 42 (2004) 609
Y. Hayase, S. Wehner, J. Küppers, and H. R. Brand
External noise imposed on the reaction-diffusion system CO
+ O2→ CO2 on Ir(111) surfaces: experiment and theory.
Phys. Rev. E69 (2004) 021609
S. Baouche, L. Hornekaer, V.V. Petrunin, A.C. Luntz,
J. L. Lemaire, T. Zecho, J. Küppers and A. Baurichter
Associative desorption dynamics of chemisorbed deuterium
atoms on graphite (0001).
ECAMP VIII, 8th European Conference on Atomic and
Molecular Physics, Rennes, France, 6-10 July 2004
A. Güttler, T. Zecho, and J. Küppers
A LEED and STM study of H(D) adsorption on C(0001)
surfaces.
Chem. Phys. Lett. 395 (2004) 171
S. Baouche, L. Hornekaer, V. V. Petrunin, J. L. Lemaire,
T. Zecho, J. Küppers, and A. Baurichter
The dynamics of associative desorption of chemisorbed D
atoms on graphite (0001).
Semaine de’l Astrophysique Francaise, Journees de la SF2A
2004, Paris, France, 14-18 June 2004
S. Wehner, Y. Hayase, H. R. Brand, and J. Küppers
Multiplicative temperature noise applied to a bistable surface reaction: experiment and theory.
J. Phys. Chem. B108 (2004) 14452
S. Baouche, L. Hornekaer, V. V. Petrunin, A. C. Luntz,
J. L. Lemaire, T. Zecho, J. Küppers, and A. Baurichter
Associative desorption dynamics of chemisorbed deuterium
atoms on graphite (0001).
Donostia International Physics Center Workshop on MOLECULE-SURFACE INTERACTIONS: ELEMENTARY
REACTIVE PROCESSES in Donostia/San Sebastián,
Spain, September 7-11, 2004
A. Güttler, T. Zecho, and J. Küppers
Adsorption of D(H) atoms on Ar ion bombarded (0001)
graphite surfaces.
Surf. Sci. 570 (2004) 218
Y. Hayase, S. Wehner, J. Küppers, and H. R. Brand
The role of sampling time in measurements of the CO2
kinetics in the bistable reaction CO + O2 → CO2 on Ir(111)
surfaces.
Physica D 2004 in press
Scientific staff
A. Güttler, D. Kolovos-Vellianitis, T. Zecho
104
University of Berlin
Lehrstuhl für Plasmaphysik
Head: Prof. Dr. Gerd Fußmann
PSI-2 Plasma Generator
The research conducted by the plasma physics
group at the Humboldt University focuses on
basic plasma physics, plasma-material interactions and highly charged ions. Two experimental devices are operated: The plasma generator
PSI-2 and an electron beam ion trap. This section gives an overview of our research projects
including results from recent EUV spectroscopic measurements and studies of shadow
phenomena in magnetized plasmas.
The electric potential within the
plasma generator has been calculated numerically within the
framework of a diploma thesis.
The potential Φ=Φ(r,z) is obtained by solving the equation
∇⋅j=0 for the current density in
the plasma region and imposing
appropriate boundary conditions for Φ on the various surfaces (cathode, anode, walls,
and floating target). Here, the
non-isotropy of the plasma must be taken into account
j=σ|| E||+σ⊥ E⊥ since the conductivities parallel (σ||) and perpendicular (σ⊥) to the field lines differ substantially. With
E=-∇Φ the components of the electric field are given by
E||=(E⋅b)b, E⊥=bx(Exb) where b=B/B. The solutions obtained yield in particular the total perpendicular current
driving the plasma rotation.
Apart from the enormous burden caused by demounting,
transferring and remounting the
whole facility we could profit
from our move (from the city to
the south eastern part of Berlin)
by improving some technical
equipment. In particular the electric power supply, the laser
excitation and vacuum systems
were upgraded. In July 2004, the first plasma at the new site
was generated. Meanwhile we have resumed our studies on
special questions of plasma-wall interactions as well as
those addressing specific problems in basic plasma physics.
With regard to the latter, the first series of experiments at the
reassembled PSI-2 was devoted to shadow effects in magnetized plasma. Shadows are a well-known phenomenon and
can be seen when, for instance, a Langmuir probe is moved
across the plasma column. An example is shown in figure 1
where the shadow manifests as a dark region with sharp
edges behind a massive half cylindrical probe being inserted
into the 8-cm-diameter plasma column. The shadow extends
over the whole distance of about 1.5 m from the probe to a
neutralizing plate at the end of the device. The plasma is
produced in the cathode-anode region and streams – from
left to right – parallel to the magnetic field lines (B≈0.1 T)
towards the neutralizer plate. The photograph shows the
shining plasma together with a heat flux sensor blocking
nearly the full upper half of the cross section. Although such
shadows are omnipresent phenomena the underlying physics
is still largely unclear. Using Langmuir probes and different
plasma spectroscopic techniques, we have started systematic
measurements in front of and behind obstacles and diaphragms of various shapes. An unexpected result is that the
electron temperature and density in the dark shadow regions
is only marginally reduced compared to the values found in
the non-shadowed regions. On the other hand, the overall
electron density is drastically reduced compared to the case
without probes. A better understanding of these phenomena
will be important not only for our PSI-2 device, but is also
of great relevance for magnetized plasmas in contact with
limiters.
The 3D Monte-Carlo code ERO was used to analyse experimental results from the study of the generation and transport
of hydrocarbons. As one result, the fluxes of the various
species impinging on the collector plate were obtained.
Scaling these fluxes with the specific sticking coefficients
and summing over all species, the total number of hydrocarbons forming the a-C:H film is obtained. For a given flux of
CH4 or C2H4, the rate of film production can thus be predicted and compared with experimental values. An agreement
within a factor of two is found in most cases, but larger differences between experiment and prediction can occur at
low densities. Further investigations were carried out to
study the effect of the electron density on the deposition
rate. For ne≈1019 m-3, the ERO calculations predict a maximum, which can be understood as arising from the combination of increasing probability to decompose the injected
hydrocarbons on one hand and enhancing the probability to
loose these by cross-field diffusion. These activities will be
continued within the framework of an EFDA project.
Several further topics were covered by the PSI-2 group:
An experimental investigation of the angular dependence of
particle and energy fluxes to solid targets was conducted
(PhD. Thesis, B. Koch: Angular Resolved Measurements of
Particle and Energy Fluxes to Surfaces in Magnetised Plasmas) the results of which are of great importance for the
evaluation of probe measurements.
Figure 1: Plasma shadow in the PSI-2 device
105
University of Berlin
Electron Beam Ion Trap (EBIT)
After seven years of successful operation of EBIT at the IPP
it was transferred to the Humboldt University in 2003 and
rebuilt at the new location in Berlin Adlershof. EBIT was
reassembled over a period of three months and went into full
operation in April 2004. The major fields of activity at EBIT
are X-ray and extreme ultraviolet (EUV) spectroscopic
measurements, extraction of ions for collision experiments
with an external target, and study of general trap physics
(sawtooth oscillations).
Investigation of the sawtooth behaviour in EBIT (see Annual
Report 2002) is in progress. In order to correlate the effect
with processes in the trap a new rate equation model is being
developed for simulation of mixed ion ensembles. Besides
the commonly used rate equations for the ion density and
temperature, the new code incorporates the Poisson equation
self-consistently. The electron beam profile is represented
by a Gaussian distribution and the ion’s transport in the radial direction is treated via cross-field diffusion using a fluidlike description. We have started to carry out calculations for
one species (Ar) to evaluate different modelling approaches.
The next step will be to extend the calculations to mixed ion
ensembles.
Figure 2: Spectrum from high-charge-state xenon ions between 105 and
115 Å. The labels in the 3rd order diffraction spectrum indicate the charge
state of the emitting ion.
spectrum excited by a 550 eV, 10 mA electron beam observed in first and third order diffraction. Due to the close
spacing of the lines, they could only be separated well enough in third order. The lines represent resonance transitions
in ions having open 4p or 4d subshells in the ground configuration. To support the identification of the lines, wavelengths and intensities were calculated using the HULLAC
computer package combined with a collisional-radiative
model (in co-operation with the Racah Institute of Physics,
Jerusalem). For the higher ionisation stages (Cu- and Znlike xenon) good agreement is found between our EBIT
measurements, predictions by HULLAC and previous studies at the TFR, PLT, and TEXT tokamaks. However, for the
lower charge states an increasing discrepancy between
observed and predicted wavelengths is noted; the values calculated with HULLAC are systematically too low. Several
lines previously seen in tokamak spectra but not labelled
with the emitting ion or transition can now be identified
with the EBIT technique and classified with the corresponding transition.
Development of the beamline for guiding extracted ions
from the trap to external analyses and experiment systems
was continued. In order to retard the extracted ions and gain
control over the angular momentum-sensitive capture in
charge exchange collisions, we have equipped the beamline
with a deceleration unit. A new solid state detector at the gas
target can measure X rays at a much higher collection efficiency. Yet another activity is complementing the beamline
with an electromagnetic filter (Wien filter) to allow separation of ions for charge-state selective collision experiments.
As part of our program to generate atomic physics data in
support of fusion work, the Berlin EBIT has been used to
measure the radiation from highly charged xenon ions.
Xenon has been proposed as a coolant for the plasma edge
region of future large tokamaks, such as ITER, and to estimate the radiated power, knowledge of the transitions giving
rise to line emission is an essential issue. EBIT has the capability to excite ions of a particular, narrow charge state distribution and, in conjunction with our grazing incidence
spectrometer, allows measurements of EUV emission lines
over a wide range of charge states and wavelengths. We have
performed scans of the line radiation for ions with charge
state 16+ (Sr-like xenon) to 25+ (Cu-like xenon) in the
wavelength range between 40 and 350 Å. More than 90 individual lines could be registered and identified, some of them
were measured for the first time. Figure 2 shows a xenon
Scientific Staff
F. Allen1, M. Baudach, P. Bachmann1, H. Beyer1,
C. Biedermann1, W. Bohmeyer1, B. Koch, T. Lunt,
R. Radtke1, S. Sadykova2, D. Schröder1.
1IPP,
Garching and Greifswald
scholarship holder
2DAAD
106
University of Kiel
Lehrstuhl für Experimentelle Plasmaphysik
Head: Prof. Dr. Ulrich Stroth
Diagnostic developments
The torsatron TJ-K is operated with a magnetically confined low-temperature plasma in order
to investigate drift-wave turbulence and wave
propagation. In 2004, new diagnostics have
been developed and used for measuring the
spatio-temporal evolution and scaling properties of coherent structures. Wavelet techniques
have been used to study the intermittency in
turbulent transport.
direction, bundles of eight
probes, which are stacked in
toroidal direction, are mounted
on carriers. The vertically
(poloidally) oriented probe tips
have a length of 4 mm. The
matrix is centred on a variable
radial position and has a spatial
resolution of 1 cm. Ion-saturation current fluctuations at 64
positions are simultaneously
acquired by means of a 64-channel transient recorder.
For the investigation of turbulence in magnetised plasmas,
the cross-phase between density
and plasma potential fluctuations is a key parameter. In the
majority of the experimental
studies, the floating potential of
a Langmuir probe is used as an
estimate for the plasma potential. It is well known, however, that plasma and floating
potential fluctuations can have different phases if temperature fluctuations are present. A diagnostic giving a direct
estimate of the plasma potential is the emissive probe. For a
detailed comparison, measurements of radial turbulent
transport have been carried out with a conventional transport
probe and a transport probe equipped with two emissive
probes. Profiles of mean values and fluctuations of the
parameters have been compared. The deviation of the mean
plasma potential from the floating potential is larger than
expected from simple probe theory. The measurements of
fluctuations, however, which are relevant for turbulence
studies, do not show a significant deviation. Spectra, the
probability density functions (PDFs) and the moments of it
resulting from cold and emissive probes agree very well.
Intermittency
The stiffness of electron and ion temperature profiles in
fusion plasmas has been interpreted as a sign of a critical
gradient similar to that of a sand pile in a state of self-organised criticality (SOC). As a consequence, intermittent transport fluctuations and power spectra which decay as 1/f, f
being the frequency, can be expected and have been
observed indeed in a number of experiments. However, from
the observations of intermittency and 1/f spectra, the SOC
state of the plasma cannot be concluded. In order to investigate whether the intermittent behaviour of plasma turbulence is due to SOC, data from the weakly driven plasma in
TJ-K and from the DALF3 turbulence code running with a
fixed background pressure gradient have been analyzed;
both systems are not expected to develop SOC.
The intermittency has been investigated by means of wavelet
analyses. The power spectra of experimental and simulated
fluctuation data turn out to be remarkably similar. Three frequency ranges could be distinguished: a flat low-frequency
range where the scale-separated time traces create Gaussian
PDFs, an intermediate one with a 1/f decay and a moderately peaked PDF, followed by a range where the spectrum
decays steeply with a strongly peaked PDF. Hence intermittency is generated primarily at high frequencies and the
transport fluctuations exhibit a substantial amount of intermittency even though they cannot develop into a state of
SOC.
Scaling properties of turbulent eddies
The scaling of the turbulent scale length L and time scale τ
have been studied. Drift-wave turbulence predicts linear
dependences of L on the drift-scale ρs and of τ on the inverse
sound velocity, which result in a gyro-Bohm scaling of the
diffusivity. Most scaling studies are carried out on confinement times or diffusivities. The scalings of these quantities
are, however, a consequence of the microscopic ones using
simple mixing-length estimates. The probe matrix has been
used to measure the 2-dimensional trajectory of quasi-
Figure 1: 8×8 Langmuir probe matrix
For investigating the turbulent structure perpendicular to the
magnetic field, the 64-tip Langmuir probe array depicted in
Figure 1 has been developed. The probes are set up on an
8×8 matrix and are located inside the confinement region. In
order to minimise the effective size of the array in poloidal
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University of Kiel
coherent turbulent structures in discharges, where ρs has
been changed by a factor of 10 by using the working gases
H, D, He, Ne and Ar. figure 2 shows the measured radial
correlation lengths versus the drift parameter. The increase
of the size of the dominant structure with ρs is apparent.
Regression analyses yielded the following results: For small
requires 3D investigations. To this end, a combination of a
2D-movable probe and the 8×8 probe matrix located at different toroidal positions has been used to measure the correlation of turbulent structures parallel to the field lines. This
has been done in the two toroidal directions with a short
connection length of 1.25 m and a long connection one of
2.5 m. The investigation requires detailed knowledge of the
mapping of the magnetic field lines between reference and
matrix position. The field-line tracing has been done with
the GOURDON code and verified with a thermionic micro
discharge from a small negatively biased hot cathode at the
location of the reference probe to the matrix.
For all gases, ion-saturation-current fluctuations have been
acquired simultaneously from reference probe and entire
matrix. The parallel dynamics has been extracted from the
correlation. Maximum correlation is found displaced from
the connecting magnetic field line. Hence the turbulent
structure is truly three-dimensional. figure 3 shows a compilation of the observed averaged displacements for all gases.
The displacement is into the same direction and has the
same value for long and short connections.
Furthermore, the correlation analysis gives a significant
time delay between reference probe and occurrence of maximum correlation on the matrix. The results are consistent
Figure 2: Poloidal and radial correlation lengths Lθ and Lr for the gases
hydrogen, deuterium, helium, neon and argon in a log-log plot. The straight
line depicts Lθ =Lr.
ρs, represented by H and D plasmas, scalings of L and τ are
close to linear. Nevertheless, the scaling of the diffusivity
turns out to be in-between Bohm- and gyro-Bohm. This
demonstrates that the scaling studies carried out on diffusivities have to be interpreted with caution. Including heavier
ions in the analysis leads to successively weaker scalings. A
further complication arises from the cross-phase, which
modifies the diffusivity and the scaling. Consistently with
previous studies, cross-phases between poloidal electric
field and density fluctuations close to π/2 have been found.
A decrease of the cross-phase is observed from hydrogen to
deuterium, which turns the Bohm-like scaling of the diffusivity into a gyro-Bohm-like one. If all ions are included, the
scaling of the diffusivity remains Bohm-like. Absolute values of the turbulent diffusivity are consistent with those
measured in the edge of fusion plasmas if the cross-phase is
taken into account. The values re-scaled to fusion parameters using a scaling for global confinement times are in the
range of 0.2-2.0 m2.
Figure 3: Absolute value of the displacement of the structure from the field
line along the short and the long connection length”
with a picture, where the largest turbulent structures start
from the reference probe located in a bad curvature region
and propagate poloidally into the electron diamagnetic
direction while they expand in parallel direction.
Parallel turbulent structure
Scientific Staff
The distinguished characteristic of drift waves is a finite
parallel wavelength. Therefore a detailed understanding
F. Greiner, T. Happel, A.. Köhn, N. Mahdizadeh, P. Manz,
B. May, M. Ramisch, K. Rahbarnia, U. Stroth
108
Technical University of München
Real-time speckle metrology for surface diagnostics
Head: Prof. Dr.-Ing. Alexander W. Koch
Introduction
The cooperation of IPP and
Technische Universität München
is concentrated on the development of Speckle measurement
techniques to detect arc traces,
deformation, erosion, surface
roughness, surface structure,
and surface contour in the divertor region of experimental
fusion devices.
In the area of surface metrology the major time
consuming bottleneck is the step of signal processing. Significant progress has been achieved
by executing the image processing algorithms
in a standard PC graphic hardware – up to now
mainly used for computer games. Using a standard graphic hardware renders special hardware like FPGAs or DSPs unnecessary. The
described methods and results are also transferable to other measurement technologies requiring high speed image processing.
The pixel shader as an image
processing unit
Starting with DirectX 8.0 programmable units within the
graphics processing unit (GPU)
for vertex and pixel operations
were introduced - the so called
vertex and pixel shaders. The
first units offered very limited
capabilities not usable for scientific operations. The new
Phase extraction in speckle metrology
Unlike in classical interferometry where the relevant phase
information is directly visible in the interferogram the phase
in speckle interferometry has to be retrieved using special
algorithms. A typical phase image is shown in figure 1. The
fringes seen in the phase image are the “contour lines” of the
measured surface. A popular method to extract the phase
information out of the interferograms is the one of
Hariharan-Schwider [1]:
where I1..I4 represent image intensities. arctan2 is unambiguous in the range [-π..π]. Besides the described phase
reconstruction algorithms an algorithm in the frequency
domain (Takeda algorithm [2]) reads as:
where fft2 is the 2D-fast-fourier-transformation, fft2-1 the
Figure 1: Typical phase image of a contour measurement.
generation of graphic chips (like the ATI R3xx family) capable of executing DirectX 9.0 functions offer shader functionality which makes them suitable for image processing: floating point support, built in trigonometric functions and
C-like programming are the most important ones. The high
processing power of the GPU is the result of many optimizations within the architecture of the chipset:
• superscalarity resulting in high parallelism
• SIMD (single instruction multiple data) structure
• RISC (reduced instruction set computer) architecture
• very high memory bandwidth
These optimizations combined with the fact that neither a
board design nor an extra high speed data link is necessary
often make the GPU superior to DSP or FPGA solutions.
figure 2 shows the complete 3D pipeline of modern graphic
chips. It is obvious that the architecture is optimized for rendering 3D scenes. These scenes are built with geometry data
inverse equivalent and M a filter matrix. The Takeda algorithm has significant benefits, especially in vibrating environments. The algorithms described require high computing
power. In case of Hariharan-Schwider an arctan2 has to be
calculated for each pixel. In case of a 1000x1000 pixel CCD
and 20 frames per second this leads to 20 million arctan2
calculations per second. In case of the Takeda algorithm the
situation is even worse because an FFT and an IFFT have to
be calculated for every frame. Looking at these numbers it is
obvious that an efficient implementation of these algorithms
is necessary in order to achieve real-time capabilities
required by many applications.
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Technical University of München
compiler uses very efficient optimizers to adapt the code to
the capabilities of the used hardware.
Implementation results
The algorithms have all been implemented on an ATI R300
chip used in the ATI Radeon 9700 AIW Pro graphic card.
The realization of the Hariharan-Schwider algorithm produces a GPU load of 13.3 % running at 640x480@25 Hz.
The FFT runs with 23 fps on a 512x512 image; the complete
Takeda algorithm (FFT + filter + IFFT) runs with 11 fps.
With these results the GPU is about three times faster than a
3.0 GHz PC. These results show that the application of GPU
allow real-time measurements in speckle interferometry
References
[1] J. Schwider: New compensating four-phase algorithm for
phase-shift interferometry, Optical Engineering, 1993,
Vol. 32 No. 8, P. 1883-1885
[2] M. Takeda, H. Ina, S. Kobayashi: Fourier-transform
method of fringe-pattern analysis for computer-based topography and interferometry, JOSA 72 1982, P. 156-160
Scientific Staff
Martin Jakobi,
Thomas Zeh
Figure 2: 3D rendering pipeline
consisting of vertices which are combined to triangles. The
filling of these triangles is manipulated by the pixel shader
unit using texture images. So input images (coming from a
frame grabber for example) are treated like a texture. The
2D image processing algorithms will work on this texture.
The first steps necessary for setting up a scene suitable for
2D image processing are:
1) build a scene of two triangles combined to one rectangle
2) set the view point in that way that the line of sight is
orthogonal to the rectangle.
The setup of this scene can be performed using standard
DirectX or OpenGL commands. The pixel shader (PS) unit
executes short programs which individually change the color
of the pixels. These programs are passed to the PS during
runtime. The programs are written either in assembler or in
high level languages like HLSL (High Level Shading
Language). HLSL has been standardized by Microsoft and
directly supports many commands from trigonometry (cos,
sin, arctan2, ...) and other arithmetic functions (powers, logarithms, exponential functions, ...). The driver or backend
110
Andreas
Purde, Andreas
Meixner,
University of Stuttgart
Institut für Plasmaforschung (IPF)
Head: Prof. Dr. Ulrich Stroth
1 Plasma Heating and Current
Drive
The main topics of the co-operation are applications of millimetre waves for plasma heating,
current drive, plasma stabilisation and diagnostics. The institute contributes to the design and
construction of the ECR heating systems on
ASDEX Upgrade and W7-X. It participates in
experiments and their interpretation using
microwaves and LIF spectroscopy as plasma
diagnostic and also develops new concepts in
the field of millimetre wave technology.
operation at high plasma pressure is foreseen – a regime where
the occurrence of these modes is
highly probable. Therefore, possibilities are explored to control
or prevent such instabilities.
The NTMs are associated with
the development of magnetic
islands with an initially relatively small width. On ASDEX
Upgrade both, ECCD and
ECRH, are used to study the
MHD stability of fusion plasmas.
Recent experiments on the stabilisation of NTMs have been
performed with a configuration where the island width w is
larger than the deposition width d. However, theory predicts
that the stabilisation efficiency depends on the ratio w/d and
therefore also experimental situations may occur where
w<d. In particular it is expected that in ITER the marginal
width, where the island decays, is smaller than d. In that
case the required power may be substantially higher and it
may be necessary to deposit the power in the O-point of the
island exclusively to achieve complete suppression.
The influence of the ECCD deposition width on the stabilisation has been studied experimentally by varying the
toroidal launching angle from 0° to -25°. TORBEAM calculations have been performed to determine the radial and
poloidal location of the deposition, the profile and amount
of the driven current. Figure 1 illustrates the achieved reduction of the island size due to ECCD as a function of the
toroidal launching angle. The ratio of calculated driven current and deposition width, I/d, is shown, and the island size
reduction is normalised to the island size before applying
ECCD. For small angles ≈-5°, a clear maximum in I/d is predicted from TORBEAM corresponding to the highest current density, although the total driven current increases with
angle. For angles <-15° (broader deposition, reduced I/d)
only partial stabilisation is observed. Consistently, angles
between -15° and 0° (pure heating) show a complete stabilisation (Wmin/Wsat=0).
1.1 ECRH system on
ASDEX Upgrade
The ASDEX Upgrade experiment is developing towards a
quasi steady-state tokamak operating in so-called advanced
scenarios. An important component of this operational regime
is a powerful and flexible ECR
heating and current drive system, which is in operation at
ASDEX Upgrade since several years.
A new ECRH system is under construction, which will use
gyrotrons which can be operated at several frequencies in
the range 104-140 GHz with 1 MW output for 10 s. The tunability of the gyrotrons offers the possibility to deposit the
power in a wider range of plasma parameters. Additionally
this system will be equipped with fast steerable mirrors in
the vacuum vessel which allows the variation of the ECRH
deposition by varying the poloidal injection angle during the
discharge.
The first of these tubes (out of four) will be a two-frequency
gyrotron operating at 105 and 140 GHz. The delivery of this
tube is expected in early 2005. The transmission system is a
combination of a quasi-optical mirror line (matching of
gyrotron output beam polarisation adjustment) and a HE11
corrugated waveguide (I.D. 87 mm, for the transmission
from the gyrotron hall to the plasma), both operating at
atmospheric pressure.
For the transmission systems of the first and second gyrotron several components have been designed, manufactured
and measured. The multi-frequency operation of these systems requires broadband performance of the transmission
lines. Numerical simulations and experiments have been
performed to develop polarisers based on corrugated mirrors with optimum characteristics over a broad frequency
range. However, the possible occurrence of surface waves in
these broadband designs can cause both unacceptable heating of the mirror material and arcing. Calculations of a combination of two polarisers (polarisation twister and elliptical
polariser) with sinusoidal corrugations have shown that arbitrary polarisations can be achieved in a wide frequency
range. Numerical simulations and measurements have
shown that for sinusoidal corrugations this anomaly is then
shifted well beyond the operating frequency range.
1.3 ECR heating of high density plasmas using O2
ECRH at the second harmonic usually is launched in
X-mode due to the nearly complete absorption of this mode.
However, in plasmas with density near to or above the
X-mode cut-off density (1.25⋅1020 m-3 at 140 GHz), experiments with the O2 mode will be performed on ASDEX
Upgrade.
To cope with the incomplete single-pass absorption of the
O2 mode, in-vessel reflectors are being designed at IPF to
allow 2-pass (or multi-pass) transmission with controlled
polarisation and beam parameters. To avoid high thermal
loads on this mirror and interaction with the plasma, this
1.2 MHD stability studies on ASDEX Upgrade
The occurrence of neoclassical tearing modes (NTM), driven by the gradients of the toroidal current density and the
plasma pressure limits the energy content in a tokamak plasma. To maximise the fusion power of a future machine the
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University of Stuttgart
final mirror can be started. Transmission experiments to
benchmark the TORBEAM calculations of the ECRH
absorption are in preparation.
Figure 2: Grating profile with high efficiency for circular polarisation
Figure 1: TORBEAM calculations of the localisation, the radial deposition
width and the total driven current for different launching angles. The upper
figure shows the deposition profile for –15°, -10°, -5°, -2.5° toroidal
launching angle for constant Bt. The ratio I/d as function of the launching
1.4 Multi-beam transmission system for W7-X
In 2004, two gyrotrons (Thales pre-prototype “Maquette”
and CPI gyrotron) were operational in the ECRH system on
W7-X, thus a power of up to 800 kW per tube has been
available with pulse lengths of several minutes. The gyrotrons were used to commission a part of the transmission
system. It showed that all mirrors used so far operate without problems. Note especially, that no arcing was seen on the
corrugated surfaces of the polarizers, provided that they
were clean. The tests also confirmed the design of the
matching optics for the “Maquette”: Due to the high TEM00
mode purity of 96%, the matching mirrors M1 and M2 had
been designed as simple ellipsoidal mirrors, which only correct for the slight astigmatism of the gyrotron beam. At the
end of the single-beam line in front of the dummy load, the
intensity distribution of the beam was measured at several
positions using thermography on a PVC target inserted into
the beam path. The analysis of the data gives good agreement with the calculated parameters of the circular Gaussian
beam. In contrast, the matching optics of the CPI tube has a
preliminary design based on rough data from the supplier.
This led to sidelobes and burn spots on the concrete walls of
the beam duct; therefore a redesign of the matching mirrors is
planned once the final acceptance test of the tube is finished.
angle (upper curve) is shown in the lower figure together with the experimentally achieved reduction of the island normalised to the size without coECCD (lower curve).
mirror should have a geometry as similar as possible to the
original wall tile that it will replace. Under this condition it
is necessary to design the mirror surface as a holographic
phase grating.
Simulations of the absorption of O2 waves for ASDEX
Upgrade were done using the TORBEAM tool, estimating
the absorption efficiency to about 50% for standard H-Mode
shots with high density and high temperature. For the design
of the mirror surface, a fast grating simulation software
using the boundary element method (BEM) with attached
optimization algorithms has been developed. Highly efficient gratings (>99% for both polarizations, with a relative
phase shift of ~13°) were obtained (see figure 2), which are
a good basis for calculation of the structure of the complete
mirror.
The experimental verification for the grating designs is
underway; after this, the design and manufacturing of the
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University of Stuttgart
Design, manufacturing and installation of special mirrors
and absorbers for stray radiation continued. The design of
the short-pulse (<0.4 s) calorimeter employing water-cooled
teflon pipes as absorber was optimized. 10 calorimeters have
been manufactured and delivered by end of the year. Highpower long-pulse tests of the multi beam waveguide
(MBWG) with the stationary load are in preparation. These
are to be performed with a roof-top mirror, which has been
designed in 2004 and – after manufacturing – will be
installed in the multi-beam transmission line. The roof-top
mirror is mounted on rails and a turn-table to reflect one of
the six beams propagating forward in an outer channel of the
MBWG back via the central channel into the CW load.
The detailed design of the launchers was started. Each
launcher consists of a water-cooled diamond window with
vacuum valve, a screening tube to keep possible stray radiation away from the port and its structures, a fixed focusing
mirror and a movable plane mirror. The movable mirror
allows for two-axis steering; it is driven by two steering rods
with universal joints, which simultaneously serve as cooling
lines with bellows inside the universal joints. A prototype of
the steering rods was manufactured and tested. However, the
tests showed that improvements are necessary.
started, material has been ordered and different subsystems
have been transferred for production to industrial partners.
The assembling and final tests of the HV-units are performed at IPF in Stuttgart. The final integration tests and the
adaptation work in Greifswald in conjunction with the highvoltage, high-power PSM-supply and the series gyrotron
finally is done by experts from IPP Greifswald and IPF
Stuttgart.
Besides the work at the HV-units, IPF was also engaged in
operation support. In tight connection with the experts from
IPP Greifswald different operating situations of the highvoltage units have been successfully simulated by Pspice.
1.5 High-voltage system for gyrotron power control and tube
protection
The development and assembly of prototypes of the highvoltage control system for the 140 GHz gyrotrons at W7-X
have been continued. In March 2004 the first prototypes of
this equipment have been delivered to IPP in Greifswald.
This control system consists mainly of two units: Firstly, a
high-voltage modulator providing the gyrotron`s body voltage (see figure 3). This unit is able to deliver modulated
body voltages up to 30 kV at a rise time of up to 600 V/µs. It
also monitors currents and voltages of the gyrotron via optical fibre links. Secondly, a crowbar with thyratron-switch
and integrated heater supply for the gyrotrons cathode. It
works as a protection unit in case of technical problems
(overcurrent, overvoltage, arcing) at the gyrotron with a
switch-off time of <500 ns. The functions of the HV-control
system are internally controlled by integrated PLC (Siemens
SPS) and remote controlled via optical fibre links by a special control unit in the control centre.
The HV prototype system was tested in Greifswald together
with both gyrotrons from Thales („Maquette“) and CPI.
The tests gave satisfactory results. During the tests some
smaller design changes have been defined, which will be
considered in the series production of the equipment.
Considering the crowbar function a technical problem at
higher operating voltages was detected, which leads to a
reconstruction of the thyratron circuit. Nevertheless, at normal voltages the unit works well.
The series production of further 9 HV control units has been
Figure 3: Photograph of the high-voltage equipment showing modulator,
thyratron crowbar and snubber coil (from left to right).
1.6 ITER contributions: High-power test of a remote steering
mock up at 140 GHz
A remote steering launcher mock-up was tested successfully
at 140 GHz in Greifswald. The launcher was placed in the
beam duct and the microwave beam from the “Maquette”
gyrotron was directed by a steerable optics into the waveguide. The tests included thermographic recording of the
far-field patterns, measurements of the ohmic heating of the
waveguide walls and the exploration of arcing limits. After
experiments with a straight waveguide, the launcher was
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modified by integrating 2 mitre bends, which could become
necessary to decrease the neutron radiation at the vacuum
window.
The high-power experiments confirmed the previous lowpower measurements, which were done at IPF Stuttgart, as
well as numerical calculations. Figure 4 shows the temperature pattern at the waveguide wall for a scanning angle of
11.6°; the pulse length was 8 s at a power of 500 kW. The
lower image shows a calculation of the power density in the
wall due to ohmic heating. The radiation patterns of the
antenna for various steering angles demonstrate an acceptable quality within a range of -12°<ϕ<12° which is sufficient for the stabilization of NTMs in ITER.
In the straight waveguide antenna, no arcing was observed
for the power levels of up to 700 kW and pulse lengths of up
to 10 s used for the experiments. In the set up with mitre
bends, arcing limited the power and pulse length. However,
the gyrotron could be operated with reduced power in a
pulsed regime. The tests were performed under atmospheric
pressure while for ITER, a vacuum operation if planned.
This means, that arcing is much less probable under ITER
conditions, especially if mitre bends can be avoided. This
activity was done under ITER task TW3-TPHE-ECHULA
(Contract No. FU 06 CT 2003-00156).
of incomplete absorption of the ECRH beams in the W7-X
plasma.
As an example, the microwave properties at 140 GHz
(ECRH frequency) of a sample of the baffle with a vacuum
plasma-sprayed tungsten coating have been carried out. The
measurement was done in a three-mirror resonator configuration. The technique is based on the comparison of the
quality factor of a 2-mirror reference resonator with the
quality factor of a 3-mirror resonator, which has identical
dimensions and includes the sample to be tested. The sample
showed a very high absorption, about 10 times higher than
that of solid tungsten plates, which probably is caused by the
coarse droplet structure containing voids.
2.2 Frequency diplexers for oversized waveguides
The development of diplexers for combining and splitting
microwaves at two different frequencies was continued. Two
types of diplexers have been realized, one where the input
and output waveguides have the same direction as the main
waveguide and one where the input and output waveguides
are inclined by an angle. In both cases, the principle is that
the TE10 fields of the input waveguides are reproduced
symmetrically for one frequency and antisymmetrically for
the other frequency, which ideally results in pure TE10
fields for both frequencies in the output waveguide.
While the Talbot effect allows the prediction of optimum
length for the diplexer, this can become very large, especially if the frequencies are close together. By using an optimization algorithm, it is possible to find suitable small
dimensions for diplexers, which have a theoretical overall
efficiency of more than 95 % even for frequencies which
differ only slightly.
Both diplexers (spatial diplexer at 45/70 GHz, angular
diplexer at 150/160 GHz) were manufactured and their
properties could be verified experimentally. It should be
noted, that the measured transmission loss is always less
than 2 dB at the centre frequencies.
In addition, the measurements confirm the bandpass characteristic near the centre frequency, which makes such types of
diplexers interesting for reflectometry systems. Other possible applications are ECH systems at 2 different frequencies
in experiments, where the available space prevents the usage
of 2 antennas.
Figure 4: Temperature pattern at the waveguide wall, top: infrared image,
bottom: calculation.
2.3 Microwave beam propagation and diagnostics
Existing computer codes concerning microwave beam propagation and analysis were improved and adapted to actual
requirements, and new codes for special problems were
developed. Thus, the performance of the code for beam
mode analysis could be enhanced further, and it was successfully applied to analyzing beam profiles from calculations or low-power measurements for various gyrotrons
(W7-X 140 GHz “Prototype”, FZK 170 GHz coaxial gyro-
2 General developments in millimetre wave technology
2.1 Investigations of materials for in-vessel components and
absorbers
The microwave-specific characterisation of the in-vessel
components for W7-X was continued. These data are essential to estimate the thermal loads of the components in case
114
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tron, and others) and also from near-field measurements at
the exit of the test mock-up for the ITER remote-steering
waveguide antenna. For example, the analysis of the lowpower measurement of the output beam of the FZK 170
GHz coaxial gyrotron yields a TEM00-efficiency of 89.3 %.
A new code was written to rectify thermographic pictures
from planes oblique to the optical axis of the camera, and it
was applied to thermography of the ITER waveguide antenna (see chapter 1.6, figure 4) as well as to high-power measurements of the beams from the final 140 GHz “Prototype”
and the 170 GHz coaxial gyrotrons. New programs to evaluate thermographic measurements of high-power microwave
beams are in the test status.
Optical fibres transmit the high-energy laser pulses produced by a Nd:YAG-pumped dye-laser as well as the LIF
signal. This technique offers a high flexibility to the system.
Theoretical studies indicated that a broad parameter range
exists, where LIF should be detectable in the power range
between the minimum energy, which had to be transmitted
to have an appropriate signal-to-noise ratio, and the maximum power the fibre optics can transmit without being damaged. A system to detect laser-induced fluorescence in the
divertor plasma of ASDEX Upgrade has been installed and
tested. A pulse energy of 5.3 mJ has been measured inside
the divertor. The laser wavelength was calibrated using optogalvanical spectroscopy and a Burleigh wavemeter.
3 Plasma Diagnostics
First LIF signals for deuterium and helium were obtained
from Dα at λ=656.107 nm with a liftime of 11.3 ns. The
expected value is 10 ns. A He I signal was observed at
λ=667.815 nm (figure 5). The calculated lifetime of 15.7 ns
shows a very good agreement with the measured value of
15.4 ns. The LIF signals occur infrequently and the reason
for this behaviour is not yet understood. The missing overlap
of neutral density and electron density (since the electrons
deliver the collisional excitation energy) within the observation volume may be one explanation. Another one is a possibly too low detection sensitivity which might only allow to
detect LIF photons during Edge Localized Modes (ELMs).
A further reason could be a saturation of the photomultiplier. The optical path of the laser as well as the detection lines
were redesigned to have 4 laser lines and 4 detection lines of
sight, which allow us to have 16 observation volumes. In the
last shutdown phase, this modified system was installed in
the ASDEX Upgrade Divertor. The detection system with
the photomultiplier will be improved to exclude a possible
saturation of the signals.
3.1 Millimetre wave diagnostics
A Finite-Difference Time-Domain Code is used to obtain
numerical full-wave solutions for the propagation of electromagnetic waves in magnetised plasmas. The code can handle O-mode and X-mode wave propagation as well as mode
conversion problems.
Doppler reflectometry is a diagnostic method for the investigation of propagating density perturbations. Whereas in a
standard reflectometer transmitter and receiver antennas are
oriented perpendicularly to the plasma surface the Doppler
reflectometer probes the plasma by a microwave signal with
a line of sight which is non-perpendicular with respect to the
reflecting layer. The diagnostic selects density perturbations
with finite wave number in the reflecting layer defined by
the tilt angle. For a given propagation velocity of these fluctuations this leads to a Doppler shift of the returning
microwave. The code is now used to calculate the instrument
function for a given geometry of the reflectometer (c.f. section 6.1 in the Garching report). Numerically calculated turbulence is implemented into the numerical reflectometer to
investigate the resolution in real space and wavenumber
space.
The code is also used to study mode conversion in a 2-D
geometry. It allows to calculate the exact solution for the
propagation of electromagnetic waves in parameter regimes
where WKB solutions are not applicable because of steep
density gradients in the refractive index of the plasma.
Initial calculations were performed for ECRH experiments
on the WEGA stellarator.
3.3 Determination of the atomic data for Silicon I
In addition to the determination of the spatial distribution of
the ground state density of silicon from the line ratios of the
Si I multiplet at 251 nm the determination of the electron
temperature and electron density from the line ratios was
farther improved. The determination of these parameters
requires an atomic model for silicon. The atomic model and
the electron collisonal excitation coefficients to the relevant
energy levels were calculated in a co-operation with
H. P. Summers, Strathclyde University (Scotland), using
modelling of the Si atom with the code SUPER STRUCTURE and R-Matrix calculations for cross section especially for low energies near threshold. The numerical results are
in a good agreement with the NIST data. This calculation
includes more than 30000 transitions, which has to be
reduced by including pseudo states.
3.2 Spectroscopic measurements of plasma parameters in
the divertor of ASDEX Upgrade
Laser-Induced Fluorescence (LIF) offers the possibility to
spectroscopically measure velocity distributions and particle
densities with high spatial resolution. Therefore LIF is used
to investigate the divertor plasma of ASDEX Upgrade.
115
University of Stuttgart
V. Erckmann, P. Brand, H. Braune, G. Dammertz,
G. Gantenbein, W. Kasparek, H. P. Laqua, G. Michel,
G. A. Mueller, M. Thumm and the W7-X ECRH teams at IPP,
FZK and IPF: The 10 MW ECRH and CD System for W7-X:
Status and first tests. 31st EPS Conf.on Plasma Phys. London,
2004, Europhysics Conference Abstracts Vol. 28G, P-1.197
G. Gantenbein, V. Erckmann, W. Kasparek, B. Plaum,
H. P. Laqua, G. Michel, K. Schwörer, A. Bruschi, S. Cirant,
F. Gandini, A. G. A. Verhoeven: High-power tests of a remote
steering concept for ECRH/ECCD at ITER. In: Proc. of 29th
Joint Int. Conf. on Infrared and Millimeter Waves and 12th
Int. Conf. Terahertz Electronics in Karlsruhe 2004, ed. by
M. Thumm, W. Wiesbeck and S. Illy, ISBN 0-7803-8490-3,
291-292.
G. Gantenbein, W. Kasparek, B. Plaum, K. Schwörer,
M Grünert, V. Erckmann, F. Hollmann, L. Jonitz, H. Laqua,
G. Michel, F. Noke, F. Purps, A. Bruschi, S. Cirant,
F. Gandini, A. G. A. Verhoeven, ECRH groups at IPP
Greifswald, FZK Karlsruhe and IPF Stuttgart: High-power
tests of a remote steering Launcher mock-up At 140 GHz.
Proc. of the Joint workshop on ECE and ECRH EC-13,
Nizhny Novgorod 2004, ed. A. Shalashov,
http://www.ec13.iapras.ru/on-line-papers.htm,
to be published.
H. Greuner, M. Balden, B. Boeswirth, H. Bolt, R. Gadow,
P. Grigull, G. Hofmann, T. Huber, W. Kasparek, H. Kumric,
S. Lindig, G. Matern, M. Mayer, R. Neu, H. Renner, J. Roth,
M. Riegert-Escribano, J. Simon-Weidner, R. Wacker:
Evaluation of vacuum plasma-sprayed boron carbide protection for the stainless steel first wall of Wendelstein 7-X. J.
Nucl. Materials 329-333 (2004) 849-854.
M. Hirsch and E. Holzhauer: Doppler reflectometry with
optimized temporal resolution for the measurement of turbulence and its propagation velocity. Plasma Phys. Control.
Fusion 46 (2004), 593-610.
G. D. Conway, J. Schirmer, S. Klenge, W. Suttrop, and
E. Holzhauer: Plasma rotation profile measurements using
Doppler reflectometry. Plasma Phys. Control. Fusion 46
(2004), 951-970.
T. Kubach, P. Lindner, A. Kallenbach, U. Schumacher and
the ADEX-Upgrade Team: Development of a Laser-Induced
Fluorescence system to detect densities and velocity distributions in the boundary layer of ASDEX Upgrade. 31st EPS
Conf. on Plasma Phys. London, 2004, Europhysics Conference Abstracts Vol. 28G, P-4.138.
Figure 5: LIF signal from He I at λ=667.815 nm.
5 Selected publications and conference reports
F. Leuterer, G. Grünwald, F. Monaco, M. Münich, F. Ryter,
H. Schütz, D. Wagner, H. Zohm, T. Franke, G. Dammertz,
R. Heidinger, K. Koppenburg, M. Thumm, G. Gantenbein,
W. Kasparek, G. G. Denisov, A. Litvak, V. Zapevalov: Progress in
the new ECRH System for ASDEX Upgrade. In: Proc. of 29th
Joint Int. Conf. on Infrared and Millimeter Waves and 12th Int.
Conf. Terahertz Electronics, Karlsruhe 2004, ed. by M. Thumm,
W. Wiesbeck and S. Illy, ISBN 0-7803-8490-3, 219-220.
D. Wagner, F. Leuterer, G. Gantenbein, E. Holzhauer,
W. Kasparek: Polarizer design for multi-frequency highpower ECRH transmission lines. In: Proc. of 29th Joint Int.
Conf. on Infrared and Millimeter Waves and 12th Int. Conf.
Terahertz Electronics, Karlsruhe 2004, ed. by M. Thumm,
W. Wiesbeck and S. Illy, ISBN 0-7803-8490-3, 259-260.
M. Maraschek, G. Gantenbein, T.P. Goodman, S. Günter,
F. Leuterer, A. Mück, O. Sauter, H. Zohm, ASDEX Upgrade
Team: Active control of MHD instabilities by ECCD in
ASDEX Upgrade. 20th IAEA Fusion Energy Conference,
(2004), Paper IAEA-CN-116/EX/7-2.
O. Mangold, W. Kasparek, E. Holzhauer: Optimization of
microwave reflection gratings for electron cyclotron resonance heating in O2-mode. In: Proc. of 29th Joint Int. Conf.
on Infrared and Millimeter Waves and 12th Int. Conf.
Terahertz Electronics in Karlsruhe 2004, ed. by M. Thumm,
W. Wiesbeck and S. Illy, ISBN 0-7803-8490-3, 717-718.
J. Shi and W. Kasparek: A Grating Coupler for In-Situ
Alignment of a Gaussian Beam – Principle, Design and LowPower Test. IEEE Trans. Antennas Propagat. AP-52 (2004)
2517-2524.
G. Dammertz, H. Braune, V. Erckmann, G. Gantenbein,
W. Kasparek, H.P Laqua, W Leonhardt, G. Michel,
G. Müller, G. Neffe, B. Piosczyk, M. Schmid, M. Thumm:
Progress in the 10 MW ECRH system for the stellarator W7-X.
IEEE Transactions on Plasma Science, PS-32 (2004) 144-151.
Scientific Staff
P. Brand, G. Gantenbein, E. Holzhauer, W.
T. Kubach, H. Kumric, P. Lindner, O.
G. A. Müller, B. Plaum, U. Schumacher, K.
R. Stirn, U. Stroth, in collaboration with IPP
FZ Karlsruhe, and IAP Nizhny Novgorod.
116
Kasparek,
Mangold,
Schwörer,
Garching,
Publications
Publications and Conference Reports
Albajar, F., M. Bornatici, G. Cortés, J. Dies, F. Engelmann,
J. García and J. Izquierdo: Electron Cyclotron Radiation
Studies Using the ASTRA Transport Code Coupled with the
Cytran Routine. 13th Joint Workshop on Electron Cyclotron
Emission and Electron Cyclotron Resonance Heating
(EC-13), 2004-05-17 till 2004-05-20, Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/albajar-1.pdf.
Atanasiu, C. V., S. Günter, K. Lackner and I. G. Miron:
Analytical solutions to the Grad–Shafranov equation.
Physics of Plasmas 11, 3510-3518 (2004).
Atanasiu, C. V., S. Günter, K. Lackner, A. Moraru,
L. E. Zakharov and A. A. Subbotin: Linear tearing modes
calculation for diverted tokamak configurations. Physics of
Plasmas 11, 5580-5594 (2004).
Albajar, F., M. Bornatici and F. Engelmann: Electron
Cyclotron Radiative Transfer in the Presence of Polarization
Scrambling in Wall Reflections. 13th Joint Workshop on
Electron Cyclotron Emission and Electron Cyclotron
Resonance Heating (EC-13), 2004-05-17 till 2004-05-20,
Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/albajar-ps.pdf.
Bachmann, P., D. Hildebrandt and D. Sünder: Nonlinear Heat
Transport in Anisotropic Divertor Targets Irradiated by Laser
Pulses. Contributions to Plasma Physics 44, 39-44 (2004).
Bäumel, S., A. Werner, R. Semler, S. Mukherjee,
D. S. Darrow, R. Ellis, F. E. Cecil, L. Pedrick, H. Altmann,
V. Kiptily, J. Gafert and JET-EFDA Contributors:
Scintillator probe for lost alpha measurements in JET.
Review of Scientific Instruments 75, 3563-3565 (2004).
Albajar, F., J. Garcia, F. Engelmann, M. Bornatici, J. Dies,
G. Cortés and J. Izquierdo: Electron Cyclotron Radiation
Transfer in Fusion Plasmas: Use of the ASTRA Transport
Code Coupled with the CYTRAN Routine. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-4.171.
Balden, M., A. F. Bardamid, A. I. Belyaeva, K. A. Slatin,
J. W. Davis, A. A. Haasz, M. Poon, V. G. Konovalov, I. V. Ryzhkov,
A. N. Shapoval and V. S. Voitsenya: Surface roughening and
grain orientation dependence of the erosion of polycrystalline stainless steel by hydrogen irradiation. Journal of
Nuclear Materials 329-333, 1515-1519 (2004).
Andreeva, T., C. D. Beidler, E. Harmeyer, Yu. L. Igitkhanov,
Ya. I. Kolesnichenko, V. V. Lutsenko, A. Shishkin, F. Hernegger,
J. Kißlinger and H. F. G. Wobig: The Helias Reactor Concept:
Comparative Analysis of Different Field Period Configurations. Fusion Science and Technology 46, 395-400 (2004).
Balden, M., E. de Juan Pardo, H. Maier, P. Starke and
U. Fantz: Chemical Erosion Behaviour of Doped Graphites
under Hydrogen Impact – A Comparison of Ion Beam Experiments and Planar Inductively Coupled RF Plasmas.
Physica Scripta T111, 123-128 (2004).
Andreeva, T., T. Bräuer, M. Endler, J. Kißlinger and
Yu. Igitkhanov: Analysis of the Magnetic Field Perturbations
During the Assembly of Wendelstein 7-X. Fusion Science
and Technology 46, 388-394 (2004).
Baldzuhn, J., L. R. Baylor, J. F. Lyon and W7-AS Team: Penetration Studies for Deuterium Pellets in Wendelstein 7-AS.
Fusion Science and Technology 46, 348-354 (2004).
Andreeva, T., T. Bräuer and J. Kißlinger: Modelling of magnetic field perturbations and correction possibilities in
WENDELSTEIN 7-X. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA
28G, European Physical Society, Geneva (2004), P-1.203.
Bandyopadhyay, M., A. Tanga, H. D. Falter, P. Franzen,
B. Heinemann, D. Holtum, W. Kraus, K. Lackner, P. McNeely,
R. Riedl, E. Speth and R. Wilhelm: Analysis of plasma dynamics of a negative ion source based on probe measurements.
Journal of Applied Physics 96, 4107-4113 (2004).
Andrew, Y., N. C. Hawkes, M. G. O’Mullane, R. Sartori,
M. N. A. Beurskens, I. Coffey, E. Joffrin, A. Loarte,
D. C. McDonald, R. Prentice, G. Saibene, W. Suttrop,
K.-D. Zastrow and ASDEX Upgrade Team: Edge ion parameters at the L-H transition on JET. Plasma Physics and
Controlled Fusion 46, 337-347 (2004).
Bandyopadhyay, M., A. Tanga, P. McNeely and V. Yaroshenko:
Comparative Measurements between Langmuir Probe and
Ion-Acoustic Wave Detection in a Radio Frequency Source.
Contributions to Plasma Physics 44, 624-628 (2004).
Bandyopadhyay, M. and R. Wilhelm: Simulation of Negative
Hydrogen Ion Production and Transport. Review of Scientific Instruments 75, 1720-1722 (2004).
Angioni, C., A. G. Peeters, X. Garbet, A. Manini, F. Ryter
and ASDEX Upgrade Team: Density response to central
electron heating: theoretical investigations and experimental
observations in ASDEX Upgrade. Nuclear Fusion 44,
827-845 (2004).
Barbato, E., G. Tardini and H. Zohm: On the use of Lower
Hybrid Current Drive in ASDEX Upgrade. 31st EPS
119
Publications and Conference Reports
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-4.130.
Bilato, R., M.-L. Mayoral, F. Rimini, M. Brambilla,
D. Hartmann, A. Korotkov, P. U. Lamalle, I. Monakhov,
J.-M. Noterdaeme, R. Sartori and JET EFDA Contributors:
JET ICRF antennas coupling on extreme plasma shapes. 31st
EPS Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-5.164.
Barradas, N. P., E. Alves, S. Pereira, V. V. Shvartsman,
A. L. Kholkin, E. Pereira, K. P. O’Donnell, C. Liu,
C. J. Deatcher, I. M. Watson and M. Mayer: Roughness in
GaN/InGaN films and multilayers determined with
Rutherford backscattering. Nuclear Instruments and
Methods in Physics Research B 217, 479-497 (2004).
Bobkov, V. V., M. Becoulet, T. Blackman, J. Brzozowski,
C. Challis, S. Gerasimov, P. U. Lamalle, M. Maraschek,
M.-L. Mayoral, I. Monakhov, J.-M. Noterdaeme, G. Saibene,
A. Walden, P. Wouters, ASDEX Upgrade Team and JETEFDA Contributors: Studies of ELM toroidal asymmetry
using ICRF antennas at JET and ASDEX Upgrade. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.141.
Bastasz, R., J. W. Medlin, J. A. Whaley, R. Beikler and
E. Taglauer: Deuterium adsorption on W(100) studied by
LEIS and DRS. Surface Science 571, 31-40 (2004).
Becker, G.: Scaling law for effective heat diffusivity in ELMy
H-mode plasmas. Nuclear Fusion 44, L26-L28 (2004).
Becker, G.: Study of anomalous inward drift in tokamaks by
transport analysis and simulations. Nuclear Fusion 44,
933-944 (2004).
Bolt, H., V. Barabash, W. Krauss, J. Linke, R. Neu, S. Suzuki,
N. Yoshika and ASDEX Upgrade Team: Materials for the
plasma-facing components of fusion reactors. Journal of
Nuclear Materials 329-333, 66-73 (2004).
Beidler, C. D., Yu. L. Igitkhanov and H. F. G. Wobig: On
Electric Fields in Stellarator Equilibria. Fusion Science and
Technology 46, 64-76 (2004).
Bolzonella, T., H. Zohm, M. Maraschek, E. Martines,
S. Saarelma, S. Günter and ASDEX Upgrade Team: High
frequency MHD activity related to type I ELMs in ASDEX
Upgrade. Plasma Physics and Controlled Fusion 46,
A143-A149 (2004).
Belo, P., P. Buratti, R. J. Buttery, T. C. Hender, D. F. Howell,
A. Isayama, E. Joffrin, M. F. F. Nave, G. Sips and JET EFDA
Contributors: Observation and implication of MHD modes
for the hybrid scenario in JET. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society, Geneva
(2004), P-1.170.
Bondarenko, I. S., O. O. Chmyga, M. B. Dreval, S. M. Khrebtov,
O. D. Komarov, O. S. Kozachok, L. I. Krupnik, I. S. Nedzelskiy
and J. Schweinzer: High intensity alkali ion sources for plasma diagnostics. Review of Scientific Instruments 75,
1826-1828 (2004).
Berk, H. L., D. E. Eremin, M. Gryaznevich, S. D. Pinches
and S. E. Sharapov: Determination of internal fields from
frequency sweeping observation. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-4.194.
Borba, D., B. Alper, G. D. Conway, I. Nunes, S. Hacquin,
D. C. McDonald, G. Maddison, P. Lomas, S. D. Pinches and
EFDA-JET Contributors: Confinement Transitions
(H-mode) in JET inner wall limiter plasmas. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.145.
Biel, W., G. Bertschinger, R. Burhenn, R. König and
E. Jourdain: Design of a high-efficiency extreme ultraviolet
overview spectrometer system for plasma impurity studies
on the stellarator experiment Wendelstein 7-X. Review of
Scientific Instruments 75, 3268-3275 (2004).
Borba, D., G. D. Conway, S. Günter, G. T. A. Huysmans,
S. Klose, M. Maraschek, A. Mück, I. Nunes, S. D. Pinches,
F. Serra and ASDEX Upgrade Team: Destabilization of TAE
modes using ICRH in ASDEX Upgrade. Plasma Physics and
Controlled Fusion 46, 809-833 (2004).
Bilato, R. and M. Brambilla: The role of collisions in the
quasilinear theory of radio-frequency heating and current
drive in nearly collisionless plasmas. Plasma Physics and
Controlled Fusion 46, 1455-1465 (2004).
Borrass, K., A. Loarte, C. F. Maggi, V. Mertens, P. Monier,
R. Monk, J. Ongena, J. Rapp, G. Saibene, R. Sartori,
J. Schweinzer, J. Stober, W. Suttrop and EFDA-JET Workprogramme
120
Publications and Conference Reports
Collaborators: Recent H-mode density limit studies at JET. Nuclear
Fusion 44, 752-760 (2004).
Engineering, Jackson Hole,WY 2003, (Eds.) G. Erickson,
Y. Zhai. AIP Conference Proceedings 707, American
Institute of Physics, Melville,NY (2004), 371-383.
Bottino, A., A. G. Peeters, O. Sauter, J. Vaclavik, L. Villard
and ASDEX Upgrade Team: Simulations of global electrostatic microinstabilities in ASDEX Upgrade discharges.
Physics of Plasmas 11, 198-206 (2004).
Caticha, A. and R. Preuss: Maximum entropy and Bayesian
data analysis: Entropic prior distributions. Physical Review
E 70, 046127 (2004).
Bradshaw, A. M. and T. Hamacher: Kernfusion: Eine nachhaltige Energiequelle der Zukunft. Nova Acta Leopoldina
N. F. 91, 339, 143-160 (2004).
Chankin, A. V.: On the poloidal localization and stability of
multi-faceted asymmetric radiation from the edge
(MARFE). Physics of Plasmas 11, 1484-1492 (2004).
Brendel, A., C. Popescu, C. Leyens, J. Woltersdorf, E. Pippel
and H. Bolt: SiC-fibre reinforced copper as heat sink material for fusion applications. Journal of Nuclear Materials
329-333, 804-808 (2004).
Conway, G. D., J. Schirmer, S. Klenge, W. Suttrop,
E. Holzhauer and ASDEX Upgrade Team: Plasma rotation
profile measurements using Doppler reflectometry. Plasma
Physics and Controlled Fusion 46, 951-970 (2004).
Bruchhausen, M., R. Burhenn, M. Endler, G. Kocsis,
A. Pospieszczyk, S. Zoletnik and W7-AS Team: Fluctuation
measurements on the Wendelstein 7-AS stellarator by means
of repetitive lithium laser blow-off. Plasma Physics and
Controlled Fusion 46, 489-505 (2004).
Conway, G. D., B. Scott, J. Schirmer, M. Reich, A. Kendl and
ASDEX Upgrade Team: Direct measurement of Zonal flows
and Geodesic Acoustic Mode GAM oscillations in ASDEX
Upgrade using Doppler reflectometry. 31st EPS Conference
on Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-4.124.
Bucalossi, J., P. T. Lang, G. Martin, V. Mertens, J. Neuhauser,
V. Rohde, L. Fattorini and ASDEX Upgrade Team:
Supersonic Molecular Beam Fuelling at ASDEX Upgrade.
31st EPS Conference on Plasma Physics, London 2004,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European
Physical Society, Geneva (2004), P-4.115.
Cooper, W. A., T. Andreeva, C. D. Beidler, Y. Igitkhanov,
J. Kisslinger, M. Isaev and H. Wobig: Bootstrap Current and
MHD Stability in a Four-period Helias Reactor
Configuration. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-2.146.
Burhenn, R., J. Baldzuhn, R. Brakel, H. Ehmler,
L. Giannone, P. Grigull, J. Knauer, M. Krychowiak,
M. Hirsch, K. Ida, H. Maassberg, K. McCormick, E. Pasch,
H. Thomsen, A. Weller, W7-AS Team, ECRH Group and NI
Group: Impurity Transport Studies in the Wendelstein 7-AS
Stellarator. Fusion Science and Technology 46, 115-128
(2004).
Cooper, W. A., S. Ferrando i Margalet, S. J. Allfrey,
J. Kisslinger, H. Wobig, Y. Narushima, S. Okamura, C. Suzuki,
K. Y. Watanabe, K. Yamazaki and M. Y. Isaev:
Magnetohydrodynamic Stability of Free-Boundary QuasiAxissymmetric Stellarator Equilibria with Finite Bootstrap
Current. Fusion Science and Technology 46, 365-377 (2004).
Buttery, R. J., D. F. Howell, R. J. La Haye, M. Maraschek,
O. Sauter and JET-EFDA Contributors: 3/2 NTM metastability scaling towards ITER. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004),
P-1.185.
Cordey, J. G., D. C. McDonald, I. Voitsekhovitch, C. Petty,
M. de Baar, E. de la Luna, P. de Vries, G. Maddison,
P. J. Lomas, J. Snipes, J. Stober and Contributors to the
EFDA-JET Workprogramme: The Scaling of the Energy
Confinement and Transport in JET ELMy H-Modes with
the Dimensionless Physics Parameters. 31st EPS Conference
on Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), O-1.05.
Carey, C. S., I. Furno, H. Weisen, R. Behn, E. Fable and
C. Angioni: Application of the singular value decomposition
method for inversion of interferometer measurements in
fusion plasmas. Review of Scientific Instruments 75,
3411-3413 (2004).
Corre, Y., P. Andrew, T. Eich, W. Fundamenski, E. Gauthier,
J. Hogan, S. Jachmich, T. Loarer, G. Matthews, R. A. Pitts
and JET-EFDA Collaborators: Inner and outer power and
energy asymmetries during L-mode power staircase pulses
Caticha, A. and R. Preuss: Entropic Priors. Bayesian
Inference and Maximum Entropy Methods in Science and
121
Publications and Conference Reports
with forward and reversed magnetic field. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.140.
B. Piosczyk, M. Schmid, M. Thumm, S. Alberti, J. P. Hogge,
M. Q. Tran, V. Erckmann, H. P. Laqua, G. Michel,
G. Gantenbein, W. Kasparek, G. Müller, K. Schwörer,
E. Giguet, G. Le Cloarec, F. Legrand, C. Lievin and
R. Magne: The 140-GHz 1-MW CW gyrotron for the stellarator W7-X. Displays and Vacuum Electronics:
Proceedings, Garmisch-Partenkirchen 2004, (Ed.)
J. Mitterauer. ITG-Fachbericht 183, VDE-Verl., Berlin
(2004), 35-40.
Correa-Restrepo, D. and D. Pfirsch: New method of deriving local energy- and momentum-conserving Maxwell-collisionless drift-kinetic and gyrokinetic theories: conservation
laws and their structures. Journal of Plasma Physics 70,
757-797 (2004).
Dammertz, G., A. Arnold, G. Michel, J. Pretterebner and
X. Thumm: A high efficiency quasi-optical mode converter
for a 140 GHz 1 MW gyrotron. 5th IEEE International
Vacuum Electronics Conference, Monterey,CA 2004. IEEE
Operation Center, Piscataway, NJ (2004), 36-37.
Correa-Restrepo, D. and D. Pfirsch: Noether formalism
with gauge-invariant variations. Journal of Plasma Physics
70, 199-213 (2004).
Dammertz, G., S. Alberti, A. Arnold, E. Borie, P. Brand,
H. Braune, V. Erckmann, G. Gantenbein, E. Giguet,
R. Heidinger, J. P. Hogge, S. Illy, W. Kasparek,
K. Koppenburg, M. Kunze, H. Laqua, G. Le Cloarec,
F. Legrand, B. Piosczyk, M. Schmid, M. Thumm and
M. Q. Tran: Status of the 1 MW, CW gyrotrons for the stellarator
W7-X. Conference Digest of the 2004 Joint 29th International
Conference on Infrared and Millimeter Waves and 12th
International Conference on Terahertz Electronics, Karlsruhe
2004, (Eds.) M. Thumm, W. Wiesbeck. University of Karlsruhe
(TH), Karlsruhe (2004), 113-114, M4.4.
Dammertz, G., H. Braune, V. Erckmann, G. Gantenbein,
W. Kasparek, H. P. Laqua, W. Leonhardt, G. Michel,
G. Müller, G. Neffe, B. Piosczyk, M. Schmid and
M. K. Thumm: Progress in the 10-MW ECRH system for the
stellarator W7-X (invited paper). IEEE Transactions on
Plasma Science 32, 144-151 (2004).
Dannert, T. and F. Jenko: Vlasov simulations of kinetic shear
Alfvén waves. Computer Physics Communications 163,
67-78 (2004).
Dammertz, G., S. Alberti, A. Arnold, E. Borie, V. Erckmann,
G. Gantenbein, E. Giguet, R. Heidinger, J. P. Hogge, S. Illy,
W. Kasparek, K. Koppenburg, M. Kuntze, H. Laqua,
G. Lecloarec, G. Legrand, Y. Legoff, W. Leonhardt, C. Lievin,
R. Magne, G. Michel, G. Müller, G. Neffe, B. Piosczyk,
T. Rzesnicki, M. Schmid, M. Thumm and M. Q. Tran:
Development of multimegawatt gyrotrons for fusion plasma
heating and current drive. 5th IEEE International Vacuum
Electronics Conference, Monterey, CA 2004. IEEE
Operations Center, Piscataway,NJ (2004), 28-29.
Darrow, D. S., S. Bäumel, F. E. Cecil, V. Kiptily, R. Ellis,
L. Pedrick and A. Werner: Design and construction of a fast ion
loss Faraday cup array diagnostic for Joint European Torus.
Review of Scientific Instruments 75, 3566-3568 (2004).
De Fanis, A., G. Prümper, U. Hergenhahn, M. Oura,
M. Kitajima, T. Tanaka, H. Tanaka, S. Fritzsche,
N. M. Kabachnik and K. Ueda: Photoelectron recapture as a
tool for the spectroscopy of ionic Rydberg states. Physical
Review A 70, 040702(R) (2004).
Dammertz, G., S. Alberti, A. Arnold, P. Brand, H. Braune,
E. Borie, V. Erckmann, G. Gantenbein, E. Giguet,
R. Heidinger, J. P. Hogge, S. Illy, W. Kasparek,
K. Koppenburg, M. Kuntze, H. Laqua, G. LeCloarec,
F. Legrand, W. Leonhardt, C. Liévin, R. Magne, G. Michel,
G. Müller, G. Neffe, B. Piosczyk, M. Schmid, K. Schwörer,
M. Thumm and M. Q. Tran: Progress in the Development of
1 MW CW Gyrotrons for the Stellarator W7-X. 13th Joint
Workshop on Electron Cyclotron Emission and Electron
Cyclotron Resonance Heating (EC-13), 2004-05-17 till
2004-05-20, Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/dammertz.pdf.
De Juan Pardo, E., M. Balden, B. Cieciwa, C. GarciaRosales and J. Roth: Erosion Processes of Carbon Materials
under Hydrogen Bombardment and their Mitigation by
Doping. Physica Scripta T111, 62-67 (2004).
Dewar, R. L., C. Nührenberg and T. Tatsuno: Density of
states and growth-rate eigenvalue separation statistics of the
ideal interchange mode spectrum. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-5.182.
Dinklage, A., C. D. Beidler, R. Fischer, H. Maaßberg,
J. Svensson and Yu. A. Turkin: Integrated Interpretative
Transport Modelling. 31st EPS Conference on Plasma
Dammertz, G., A. Arnold, E. Borie, R. Heidinger, S. Illy,
K. Koppenburg, M. Kuntze, W. Leonhardt, G. Neffe,
122
Publications and Conference Reports
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004),
O-2.03.
FZK and IPF: The 10 MW ECRH and CD System for
W7-X: Status and first tests. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004),
P-1.197.
Dinklage, A., R. Fischer, H. Dreier, J. Svensson and
Y. Turkin: Integrated approaches in fusion data analysis.
Bayesian Inference and Maximum Entropy Methods in
Science and Engineering, Garching 2004, (Eds.) R. Fischer,
R. Preuss, U. von Toussaint. AIP Conference Proceedings
735, American Institute of Physics, Melville, NY (2004),
43-51.
Eriksson, L.-G., T. Johnson, T. Hellsten, C. Giroud, V. Kiptily,
M. Brzozowski, M. DeBaar, J. DeGrassie, M. Mantsinen,
A. Meigs, J.-M. Noterdaeme, A. Staebler, D. Testa,
A. Tuccillo, K.-D. Zastrow and K. Kirov: Plasma Rotation
Induced by Directed Waves in the Ion-Cyclotron Range of
Frequencies. Physical Review Letters 92, 235001 (2004).
Dinklage, A., R. Fischer and J. Svensson: Topics and
Methods for Data Validation by Means of Bayesian
Probability Theory. Fusion Science and Technology 46,
355-364 (2004).
Eriksson, L.-G., A. Mueck, O. Sauter, S. Coda,
M. Mantsinen, M. L. Mayoral, E. Westerhof, R. Buttery,
D. McDonald, T. Johnson, J.-M. Noterdaeme and P. de Vries:
Destabilisation of Fast-Ion-Induced Long Sawteeth by
Localised Current Drive in the JET Tokamak. Physical
Review Letters 92, 235004 (2004).
Doerner, R. P., M. J. Baldwin and K. Schmid: The Influence
of a Beryllium Containing Plasma on the Erosion Properties
of Graphite. Physica Scripta T111, 75-79 (2004).
Fantz, U.: Emission spectroscopy of molecular low pressure
plasmas. Contributions to Plasma Physics 44, 508-515 (2004).
Dose, V. and A. Menzel: Bayesian analysis of climate change
impacts in phenology. Global Change Biology 10, 259-272
(2004).
Fantz, U.: Optical Phenomena in the open air. Contemporary
Physics 45, 93-108 (2004).
Draxler, M., S. N. Markin, R. Beikler, E. Taglauer, F. Kastner,
M. Bergsmann and P. Bauer: Depth characterization of nmlayers by low energy ion scattering. Nuclear Instruments and
Methods in Physics Research B 219-220, 578-583 (2004).
Feist, J.-H. and W7-X Construction Team: Status of
Wendelstein 7-X Construction. Fusion Science and
Technology 46, 192-199 (2004).
Düchs, D. F. and R. H. Cohen (Eds.): 9th International
Workshop on Plasma Edge Theory in Fusion Devices,
3-5 September 2003, San Diego,USA: Proceedings of
Invited and Contributed Papers. Contributions to Plasma
Physics 44, 1-3. Wiley-VCH Verl., Weinheim (2004), 310 p.
Feng, Y., E. Sardei, J. Kisslinger, K. McCormick and
D. Reiter: 3D Edge Modeling and Island Divertor Physics.
Contributions to Plasma Physics 44, 57-69 (2004).
Fesenyuk, O. P., Ya. I. Kolesnichenko, V. V. Lutsenko,
H. Wobig and Yu. V. Yakovenko: Kinetic mirror-induced
Alfvén eigenmodes in Wendelstein-type stellarators. Plasma
Physics and Controlled Fusion 46, 89-104 (2004).
Dux, R., C. Giroud, K.-D. Zastrow and JET EFDA
Contributors: Impurity transport in internal transport barrier
discharges on JET. Nuclear Fusion 44, 260-264 (2004).
Fink, M. A., M. Endler and T. Klinger: New Developments of
Self-emitting Electrostatic Probes for use in High Temperature
Plasmas. Contributions to Plasma Physics 44, 668-676 (2004).
Ebeling, W., G. Fußmann, T. Klinger and K.-H. Spatschek:
Proceedings of the 5th International Workshop on Electrical
Probes in Magnetized Plasmas, 21-23 July, 2003,
Greifswald, Germany. Contributions to Plasma Physics 44,
Wiley-VCH Verl., Weinheim (2004), 571-704.
Eckstein, W., J. Roth, W. Nagel and R. Dohmen: Sputtering
mechanisms near the threshold energy. Journal of Nuclear
Materials 328, 55-61 (2004).
Fischer, R.: Bayesian experimental design – studies for
fusion diagnostics. Bayesian Inference and Maximum
Entropy Methods in Science and Engineering, Garching
2004, (Eds.) R. Fischer, R. Preuss, U. von Toussaint. AIP
Conference Proceedings 735, American Institute of Physics,
Melville,NY (2004), 76-83.
Erckmann, V., P. Brand, H. Braune, G. Dammertz,
G. Gantenbein, W. Kasparek, H. P. Laqua, G. Michel,
G. A. Mueller, M. Thumm and W7-X ECRH Teams at IPP,
Fischer, R.: Bayesian group analysis of plasma-enhanced
chemical vapour deposition data. New Journal of Physics 6,
25 (2004), http://stacks.iop.org/1367-2630/6/25.
123
Publications and Conference Reports
Fischer, R. and A. Dinklage: Integrated data analysis of
fusion diagnostics by means of Bayesian probability theory.
Review of Scientific Instruments 75, 4237-4239 (2004).
Garbet, X., P. Mantica, F. Ryter, G. Cordey, F. Imbeaux,
C. Sozzi, A. Manini, E. Asp, V. Parail, R. Wolf and JET EFDA
Contributors: Profile stiffness and global confinement.
Plasma Physics and Controlled Fusion 46, 1351-1374 (2004).
Fischer, R., R. Preuss, U. von Toussaint (Eds.): Bayesian
Inference and Maximum Entropy Methods in Science and
Engineering: 24th International Workshop on Bayesian Inference
and Maximum Entropy Methods in Science and Engineering
(MaxEnt’04), Garching 2004. AIP Conference Proceedings
735, American Institute of Physics, Melville, NY (2004), 623 p.
Geiger, J., H. Maassberg, N. B. Marushchenko, M. Romé
and A. Weller: Equilibrium calculations for the W7-AS stellarator with large internal current densities due to ECCD.
31st EPS Conference on Plasma Physics, London 2004,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European
Physical Society, Geneva (2004), P-1.207.
Gadelmeier, F., A. Herrmann, D. Hildebrandt, K. McCormick,
D. Naujoks, P. Grigull, M. Hirsch and T. Klinger: Stationary
and transient heat load in the island divertor of W7-AS.
Plasma Physics and Controlled Fusion 46, 711-721 (2004).
Geiger, J. E., A. Weller, M. C. Zarnstorff, C. Nührenberg,
A. H. F. Werner, Ya. I. Kolesnichenko, W7-AS Team and
Neutral Beam Injection Group: Equilibrium and Stability of
High-ß Plasmas in Wendelstein 7-AS. Fusion Science and
Technology 46, 13-23 (2004).
Gál, K., S. Kálvin, G. Kocsis, P. T. Lang, R. Schneider,
G. Veres and ASDEX Upgrade Team: Modeling of cryogenic
hydrogen isotope pellet ablation and cloud expansion. 31st
EPS Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-5.149.
Giannone, L., A. C. C. Sips, O. Kardaun, G. Pautasso,
F. Spreitler, W. Suttrop, C. Tichmann and ASDEX Upgrade
Team: Regime identification in ASDEX Upgrade. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-4.131.
Gantenbein, G., V. Erckmann, W. Kasparek, B. Plaum,
H. Laqua, G. Michel, K. Schwörer, A. Bruschi, S. Cirant,
F. Gandini, A.G.A. Verhoeven and ECRH Group: First HighPower Tests of a Remote Steering Concept for ECRH/ECCD
at ITER. Conference Digest of the 2004 Joint 29th
International Conference on Infrared and Millimeter Waves
and 12th International Conference on Terahertz Electronics,
Karlsruhe 2004, (Eds.) M. Thumm, W. Wiesbeck. University
of Karlsruhe (TH), Karlsruhe (2004), 291-292, Tu11.2.
Giannone, L., A. C. C. Sips, O. Kardaun, F. Spreitler,
W. Suttrop and ASDEX Upgrade Team: Regime identification in ASDEX Upgrade. Plasma Physics and Controlled
Fusion 46, 835-856 (2004).
Giroud, C., R. Barnsley, C. D. Challis, I. Coffey, R. Dux, M. von
Hellermann, E. Joffrin, C. Jupen, A. Meigs, M. O’Mullane,
V. Pericoli Ridolfini, A. C. C. Sips, A. D. Whiteford,
K.-D. Zastrow and JET-EFDA Contributors: Z-dependence of
impurity transport in steady-state ITB and Hybrid scenario at
JET. 31st EPS Conference on Plasma Physics, London 2004,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.144.
Gantenbein, G., W. Kasparek, B. Plaum, K. Schwörer,
M. Grünert, V. Erckmann, F. Hollmann, L. Jonitz, H. Laqua,
G. Michel, F. Noke, F. Purps, A. Bruschi, S. Cirant,
F. Gandini, A. G. A. Verhoeven and ECRH Groups at IPP
Greifswald, FZK Karlsruhe and IPF Stuttgart: High-power
Tests of a Remote Steering Launcher Mock-up at 140 GHz.
13th Joint Workshop on Electron Cyclotron Emission
and Electron Cyclotron Resonance Heating (EC-13),
2004-05-17 till 2004-05-20, Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/Gantenbein.pdf.
Gormezano, C., A. Becoulet, P. Buratti, L. Carraro,
F. Crisanti, B. Esposito, G. Giruzzi, R. Guirlet, G. T. Hoang,
E. Joffrin, X. Litaudon, T. Luce, V. Pericoli-Ridolfini,
O. Sauter, A. C. C. Sips, A. Tuccillo and JET EFDA
Contributors: Hybrid advanced scenarios: perspectives for
ITER and new experiments with dominat RF heating. Plasma
Physics and Controlled Fusion 46, B435-B447 (2004).
Garbet, X., P. Mantica, C. Angioni, E. Asp, Y. Baranov,
C. Bourdelle, R. Budny, F. Crisanti, G. Cordey, L. Garzotti,
N. Kirneva, D. Hogeweij, T. Hoang, F. Imbeaux, E. Joffrin,
X. Litaudon, A. Manini, D. C. McDonald, H. Nordman,
V. Parail, A. Peeters, F. Ryter, C. Sozzi, M. Valovic, T. Tala,
A. Thyagaraja, I. Voitsekhovitch, J. Weiland, H. Weisen,
A. Zabolotsky and JET EFDA Contributors: Physics of
transport in tokamaks. Plasma Physics and Controlled
Fusion 46, B557-B574 (2004).
Greenfield, C. M., M. Murakami, J. R. Ferron, M. R. Wade,
T. C. Luce, C. C. Petty, J. E. Menard, T. W. Petrie, S. L. Allen,
K. H. Burrell, T. A. Casper, J. C. DeBoo, E. J. Doyle,
A. M. Garofalo, I. A. Gorelov, R. J. Groebner, J. Hobirk,
A. W. Hyatt, R. J. Jayakumar, C. E. Kessel, R. J. La Haye,
G. L. Jackson, L. L. Lao, J. Lohr, M. A. Makowski,
124
Publications and Conference Reports
R. I. Pinsker, P. A. Politzer, R. Prater, G. M. Staebler, E. J.
Strait, T. S. Taylor, W. P. West and DIII-D Team: Advanced
tokamak research in DIII-D Plasma Physics and Controlled
Fusion 46, B213-B233 (2004).
survey data sample. Astronomical Data Analysis Software
and Systems (ADASS) XIII, Strasbourg 2003, (Eds.) F.
Ochsenbein, M. Allen, D. Egret. ASP Conference Series
314, Astronomical Society of the Pacific, San Francisco, CA
(2004), 253-256.
Greenfield, C. M., M. Murakami, J. R. Ferron, M. R. Wade,
T. C. Luce, C. C. Petty, J. E. Menard, T. W. Petrie, S. L. Allen,
K. H. Burrell, T. A. Casper, J. C. DeBoo, E. J. Doyle,
A. M. Garofalo, I. A. Gorelov, J. Groebner, J. Hobirk,
A. W. Hyatt, R. J. Jayakumar, C. E. Kessel, R. J. La Haye,
G. L. Jackson, J. Lohr, M. A. Makowski, R. I. Pinsker,
P. A. Politzer, R. Prater, E. J. Strait, T. S. Taylor, W. P. West and
DIII-D Team: High performance advanced tokamak regimes
in DIII-D for next-step experiments. Physics of Plasmas 11,
2616-2626 (2004).
Hallatschek, K.: Thermodynamic Potential in Local
Turbulence Simulations. Physical Review Letters 93,
125001 (2004).
Hallatschek, K.: Turbulent Saturation of Tokamak-Core
Zonal Flows. Physical Review Letters 93, 065001 (2004).
Hartfuss, H. J.: Fusion Plasma Diagnostics with mm-Waves,
basic principles and recent developments. Conference
Digest of the 2004 Joint 29th International Conference on
Infrared and Millimeter Waves and 12th International
Conference on Terahertz Electronics, Karlsruhe 2004, (Eds.)
M. Thumm, W. Wiesbeck. University of Karlsruhe (TH),
Karlsruhe (2004), 65-66, PLW.1.
Greuner, H., M. Balden, B. Böswirth, H. Bolt, R. Gadow,
P. Grigull, G. Hofmann, T. Huber, W. Kasparek, H. Kumric,
S. Lindig, G. Matern, M. Mayer, R. Neu, H. Renner, J. Roth,
M. Riegert-Escribano, J. Simon-Weidner and R. Wacker:
Evaluation of vacuum plasma-sprayed boron carbide protection for the stainless steel first wall of WENDELSTEIN 7-X.
Journal of Nuclear Materials 329-333, 849-854 (2004).
Heikkinen, J. A., Vl. V. Bobkov, D. A. D’Ippolito,
D. A. Hartmann, J. Myra, K. M. Rantamäki, A. Salmi,
T. Hellsten, P. U. Lamalle, M. Mantsinen,
J.-M. Noterdaeme and JET-EFDA Contributors: Experiments on ICRF Coupling with Different Phasings. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.) P.
Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-5.162.
Günter, S., J. Hobirk, K. Lackner, G. Pereverzev, A. Stäbler and
ASDEX Upgrade Team: Conditions for NBI Current Profile
Control on ASDEX Upgrade. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004), O-1.02.
Günter, S., M. Maraschek, M. de Baar, D. F. Howell, E. Poli,
E. Strumberger, C. Tichmann, ASDEX Upgrade Team and
Contributors to the EFDA-JET Workprogramme: The frequently interrupted regime of neoclassical tearing modes
(FIR-NTMs): required plasma parameters and possibilities
for its active control. Nuclear Fusion 44, 524-532 (2004).
Heimann, P., S. Heinzel, Ch. Hennig, H. Kühntopf,
H. Kroiss, G. Kühner, J. Maier, J. Reetz and M. Zilker:
Status report on the development of the data acquisition system of Wendelstein 7-X. Fusion Engineering and Design 71,
219-224 (2004).
Hennig, Ch., P. Heimann, S. Heinzel, H. Kroiss, G. Kühner,
H. Kühntopf, J. Maier, J. Reetz and M. Zilker: A concept of
online monitoring for the Wendelstein 7-X experiment.
Fusion Engineering and Design 71, 107-110 (2004).
Günther, S., F. Esch, L. Gregoratti, A. Barinov, M. Kiskinova,
E. Taglauer and H. Knözinger: Gas-Phase Transport during
the Spreading of MoO3 on Al2O3 Support Surfaces:
Photoelectron Spectromicroscopic Study. Journal of
Physical Chemistry B 108, 14223-14231 (2004).
Hergenhahn, U.: Vibrational structure in inner shell photoionization of molecules. Journal of Physics B: Molecular
and Optical Physics 37, R89-R135 (2004).
Guglielmetti, F., R. Fischer and V. Dose: Mixture modeling
for background and sources separation in x-ray astronomical
images. Bayesian Inference and Maximum Entropy
Methods in Science and Engineering, Garching 2004, (Eds.)
R. Fischer, R. Preuss, U. von Toussaint. AIP Conference
Proceedings 735, American Institute of Physics, Melville,
NY (2004), 111-118.
Hergenhahn, U., E. E. Rennie, O. Kugeler, S. Marburger,
T. Lischke, I. Powis and G. Garcia: Photoelectron circular
dichroism in core level ionization of randomly oriented pure
enantiomers of the chiral molecule camphor. Journal of
Chemical Physics 120, 4553-4556 (2004).
Herrmann, A., M. Balden, W. Bohmeyer and D. Hildebrandt:
Investigation of Infrared Emission from Carbon Micro-
Guglielmetti, F., R. Fischer, V. Dose, W. Voges and G. Boese:
Source detection with Bayesian inference on ROSAT all-sky
125
Publications and Conference Reports
structure on a 30 Micron Spatial Scale. Physica Scripta
T111, 98-100 (2004).
Igitkhanov, Yu., G. K. McCormick and P. E. Grigull: On the
High Density Modes of Operation in W7-AS. Fusion
Science and Technology 46, 101-105 (2004).
Herrmann, A., T. Eich, V. Rohde, C. J. Fuchs, J. Neuhauser
and ASDEX Upgrade Team: Power deposition outside the
divertor in ASDEX Upgrade. Plasma Physics and
Controlled Fusion 46, 971-979 (2004).
Igochine, V., S. Günter, K. Lackner and E. Strumberger:
Error field amplification in the presence of a resistive wall.
31st EPS Conference on Plasma Physics, London 2004,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European
Physical Society, Geneva (2004), P-4.129.
Hildebrandt, D. and D. Sünder: The Influence of Contamination
Layers on Surface Temperature Measurements of Carbon
Materials in Fusion Devices. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA
28G, European Physical Society, Geneva (2004), P-1.115.
Imbeaux, F., T. Fujita, A. Isayama, E. Joffrin, J. Kinsey,
X. Litaudon, T. Luce, M. Murakami, Y. S. Na, Y. Sakamoto,
A. C. C. Sips, J. F. Artaud and V. Basiuk for the ITPA Topical
Group on Transport Physics: Transport modelling of Hybrid
discharges from the ITPA Profile Database. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-4.143.
Hildebrandt, D., D. Sünder and A. Herrmann: Temperature
Measurements of Carbon Materials in Fusion Devices at
High Heat Fluxes. InfraMation 2003 Proceedings, Las
Vegas,NV 2003, (Ed.) G. Orlove. InfraMation Vol. 4,
G. Orlove (2004), 91-98.
Itoh, K., K. Hallatschek, S. Toda, S.-I. Itoh, P. H. Diamond,
M. Yagi and H. Sanuki: Collisional effects on coherent structures of zonal flows and turbulent transport. Plasma Physics
and Controlled Fusion 46, A335-A340 (2004).
Hirsch, M., H. Ehmler, J. Baldzuhn, E. Holzhauer and
F. Wagner: Dynamics of poloidal flows and turbulence at the
H-mode transition in W7-AS. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-1.206.
Jahnke, T., A. Czasch, M. S. Schöffler, S. Schössler,
A. Knapp, M. Käsz, J. Titze, C. Wimmer, K. Kreidi,
R. E. Grisenti, A. Staudte, O. Jagutzki, U. Hergenhahn,
H. Schmidt-Böcking and R. Dörner: Experimental
Observation of Interatomic Coulombic Decay in Neon
Dimers. Physical Review Letters 93, 163401 (2004).
Hirsch, M. and E. Holzhauer: Doppler reflectometry with
optimised temporal resolution for the measurement of turbulence and its propagation velocity. Plasma Physics and
Controlled Fusion 46, 593-609 (2004).
Jin, J., B. Piosczyk, G. Michel, M. Thumm, O. Drumm,
T. Rzesnicki and S. C. Zhang: The design of a quasi-optical
mode converter for a coaxial-cavity gyrotron. Conference
Digest of the 2004 Joint 29th International Conference on
Infrared and Millimeter Waves and 12th International
Conference on Terahertz Electronics, Karlsruhe 2004, (Eds.)
M. Thumm, W. Wiesbeck. University of Karlsruhe (TH),
Karlsruhe (2004), 669-670, P2.37.
Horton, L. D., G. D. Conway, A. W. Degeling, T. Eich,
A. Kallenbach, P. T. Lang, J. B. Lister, A. Loarte, Y. R. Martin,
P. J. McCarthy, H. Meister, J. Neuhauser, J. Schirmer,
A. C. C. Sips, W. Suttrop and ASDEX Upgrade Team: ITERrelevant H-mode physics at ASDEX Upgrade. Plasma
Physics and Controlled Fusion 46, B511-B525 (2004).
Horvath, K., J. Lingertat, M. Laux and F. Wagner: Langmuir
Probe Measurements in the WEGA Stellarator. Contributions to Plasma Physics 44, 650-655 (2004).
Kallenbach, A., Y. Andrew, M. Beurskens, G. Corrigan, T. Eich,
S. Jachmich, M. Kempenaars, A. Korotkov, A. Loarte,
G. Matthews, P. Monier-Garbet, G. Saibene, J. Spence, W. Suttrop
and JET EFDA Contributors: EDGE2D modelling of edge profiles obtained in JET diagnostic optimized configuration.
Plasma Physics and Controlled Fusion 46, 431-446 (2004).
Horvath, K., J. Lingertat, M. Otte and F. Wagner: Investigation of properties of the WEGA plasmas. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.212.
Kálvin, S., E. Belonohy, K. Gál, G. Kocsis, P. T. Lang,
G. Veres and ASDEX Upgrade Team: Investigation of cryogenic pellet cloud dynamics. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys, H.
Hutchinson. ECA 28G, European Physical Society, Geneva
(2004), P-5.150.
Hynönen, V., O. Dumbrajs, A. W. Degeling, T. Kurki-Suonio and
H. Urano: The search for chaotic edge localized modes in
ASDEX Upgrade. Plasma Physics and Controlled Fusion 46,
1409-1422 (2004).
126
Publications and Conference Reports
Kang, H. and V. Dose: Bayesian model comparison using
Gauss approximation on multicomponent mass spectra from
CH4 plasma. Bayesian Inference and Maximum Entropy
Methods in Science and Engineering, Jackson Hole, WY
2003, (Eds.) G. Erickson, Y. Zhai. AIP Conference
Proceedings 707, American Institute of Physics, Melville,
NY (2004), 295-302.
and ablation of cryogenic hydrogen pellet in ASDEX
Upgrade plasmas. Review of Scientific Instruments 75,
4754-4762 (2004).
König, R., P. Grigull, K. McCormick, Y. Feng, H. Ehmler,
F. Gadelmeier, L. Giannone, D. Hildebrandt, J. Kisslinger,
T. Klinger, D. Naujoks, N. Ramasubramanian, H. Renner,
F. Sardei, H. Thomsen, F. Wagner, U. Wenzel, A. Werner,
A. Komori, S. Masuzaki, A. Matsuoka, P. Mioduszewski,
T. Morisaki, T. Obiki and N. Ohyabu: Divertors for Helical
Devices: Concepts, Plans, Results, and Problems. Fusion
Science and Technology 46, 152-166 (2004).
Kasparek, W., G. Dammertz, V. Erckmann, G. Gantenbein,
M. Grünert, F. Hollmann, L. Jonitz, H. Laqua, G. Michel,
F. Noke, B. Plaum, F. Purps, T. Schultz, K. Schwörer and
M. Weissgerber: First high-power tests of the 140 GHz,
10 MW CW transmission system for ECRH on the stellarator W7-X. Conference Digest of the 2004 Joint 29th
International Conference on Infrared and Millimeter Waves
and 12th International Conference on Terahertz Electronics,
Karlsruhe 2004, (Eds.) M. Thumm, W. Wiesbeck. University
of Karlsruhe (TH), Karlsruhe (2004), 223-224, Tu3.4.
König, R., O. Ogorodnikova, D. Hildebrandt, K. Grosser,
C. von Sehren, J. Baldzuhn, R. Burhenn, P. Mertens,
A. Pospieszczyk, B. Schweer, H. Schmidt and T. Klinger:
Development of cooled UV, visible and IR windows for quasicontinuous operation of the W7-X stellarator. Review of
Scientific Instruments 75, 4258-4260 (2004).
Kastelewicz, H. and G. Fussmann: Plasma Modelling for
the PSI Linear Plasma Device. Contributions to Plasma
Physics 44, 352-360 (2004).
Kolesnichenko, Ya. I., V. V. Lutsenko, V. S. Marchenko,
A. Weller, A. H. F. Werner, H. F. G. Wobig, Yu. V. Yakovenko
and K. Yamazaki: Fast Ion Confinement and Fast-IonInduced Effects in Stellarators. Fusion Science and
Technology 46, 54-63 (2004).
Kendl, A.: Local shear damping of ion and electron temperature
gradient modes. Physics of Plasmas 11, 1810-1815 (2004).
Keudell, A. von and M. Bauer: Particle-induced oscillations
in inductively coupled plasmas. Plasma Sources Science &
Technology 13, 285-292 (2004).
Kolesnichenko, Ya. I., V. V. Lutsenko, A. Werner, H. Wobig,
J. Geiger and O. S. Burdo: Effect of the Radial Electric Field
on the Confinement of NBI Ions in Wendelstein 7-X. 31st
EPS Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.201.
Keudell, A. von and W. Jacob: Elementary processes in plasma-surface interaction: H-atom and ion-induced chemisorption of methyl on hydrocarbon film surfaces. Progress in
Surface Science 76, 21-54 (2004).
Konz, C., D. P. Coster, A. G. Peeters and ASDEX Upgrade
Team: Neoclassical Transport in the Plasma Edge at ASDEX
Upgrade with B2. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-4.122.
Kleiber, R., R. Miklaszewski and J. Nührenberg: Innovative
concepts and theory of stellarators: Report on the IAEA
Technical Meeting (Greifswald, Germany, 29 September 1 October 2003). Nuclear Fusion 44, 686-688 (2004).
Kornilov, V. and R. Kleiber: Global three-dimensional calculations of ion-temperature-gradient modes in stellarators
with a two-fluid model. Plasma Physics and Controlled
Fusion 46, 1605-1615 (2004).
Kobayash, M., Y. Feng, F. Sardei, D. Reiter, D. Reiser and
K. H. Finken: Implementation of the EMC3-EIRENE code
on TEXTOR-DED: accuracy and convergence study.
Contributions to Plasma Physics 44, 25-30 (2004).
Kornilov, V, K. Kleiber, R. Hatzky, L. Villard and G. Jost:
Gyrokinetic global three-dimensional simulations of linear
ion-temperature-gradient modes in Wendelstein 7-X.
Physics of Plasmas 11, 3196-3202 (2004).
Koch, F., R. Brill, H. Maier, D. Levchuk, A. Suzuki,
T. Muroga and H. Bolt: Crystallization behavior of arcdeposited ceramic permeation barrier coatings. Journal of
Nuclear Materials 329-333, 1403-1406 (2004).
Korotkov, A. A., P. D. Morgan, J. Vince, J. Schweinzer and JET
EFDA Contributors: Line ratio method for measurement of
magnetic field vector using Li-multiplet (22S-22P) emission.
Review of Science Instruments 75, 2590-2602 (2004).
Kocsis, G., S. Kálvin, G. Veres, P. Cierpka, P. T. Lang,
J. Neuhauser, C. Wittmann and ASDEX Upgrade Team: A
fast framing camera system for observation of acceleration
127
Publications and Conference Reports
Krychowiak, M., R. König, R. Fischer and T. Klinger:
Bayesian analysis of the effective charge from spectroscopic
bremsstrahlung measurement in fusion plasmas. Journal of
Applied Physics 96, 4784-4792 (2004).
M. Kaufmann, G. Kocsis, A. Lorenz, M. E. Manso,
M. Maraschek, V. Mertens, J. Neuhauser, I. Nunes, W. Schneider,
W. Suttrop, H. Urano and ASDEX Upgrade Team: ELM pace
making and mitigation by pellet injection in ASDEX
Upgrade. Nuclear Fusion 44, 665-677 (2004).
Kubach, T., P. Lindner, A. Kallenbach, U. Schumacher and
ASDEX Upgrade Team: Development of a laser-induced fluorescence system to detect densities and velocity distributions in the divertor plasma of ASDEX Upgrade. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-4.138.
Lang, P. T., A. W. Degeling, J. B. Lister, Y. R. Martin,
P. J. McCarthy, A. C. C. Sips, W. Suttrop, G. D. Conway,
L. Fattorini, O. Gruber, L. D. Horton, A. Herrmann,
M. E. Manso, M. Maraschek, V. Mertens, A. Mück, W. Schneider,
C. Sihler, W. Treutterer, H. Zohm and ASDEX Upgrade Team:
Frequency control of type-I ELMs by magnetic triggering in
ASDEX Upgrade. Plasma Physics and Controlled Fusion 46,
L31-L39 (2004).
Kühner, G., P. Heimann, Ch. Hennig, H. Kühntopf,
H. Kroiss, J. Maier, J. Reetz and M. Zilker: Editor for system
configuration and experiment program specification. Fusion
Engineering and Design 71, 225-230 (2004).
Laqua, H. P., V. Erckmann, W7-AS Team and ECRH-Group:
Transmission Measurement with high Power ECRH at the
W7-AS Stellarator. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-1.209.
Kugeler, O., G. Prümper, R. Hentges, J. Viefhaus, D. Rolles,
U. Becker, S. Marburger and U. Hergenhahn: Intramolecular
Electron Scattering and Electron Transfer Following Autoionization in Dissociating Molecules. Physical Review
Letters 93, 033002 (2004).
Laux, M.: How to Interpret Triple Probe Measurements
when Non of the Tips Saturates? Contributions to Plasma
Physics 44, 695-699 (2004).
Kugeler, O., E. E. Rennie, A. Rüdel, M. Meyer, A. Marquette and
U. Hergenhahn: N2 valence photoionization below and above
the 1s-1 core ionization threshold. Journal of Physics B: Atomic,
Molecular and Optical Physics 37, 1353-1367 (2004).
Laux, M., H. Klauß, L. Haupt, B. Köhler, E. Chilla and
C. M. Flannery: Mechanical and Sound Investigations of Advanced
Carbon Materials. Physica Scripta T111, 184-189 (2004).
Kurzan, B., M. Jakobi, H. Murmann and ASDEX Upgrade
Team: Signal processing of Thomson scattering data in a
noisy environment in ASDEX Upgrade. Plasma Physics and
Controlled Fusion 46, 299-317 (2004).
Laux, M., W. Schneider, B. Jüttner, M. Balden, S. Lindig, I. Beilis
and B. Djakov: Ignition and Burning of Vacuum Arcs on
Tungsten Layers. Proceedings: ISDEIV, XXIth International
Symposium on Discharges and Electrical Insulation in
Vacuum, Yalta, Crimea Peninsula 2004. IEEE Operations
Center, Piscataway, NJ (2004), 57-61.
Kuteev, B. V., Yu. V. Martynenko, V. G. Skokov, V. Yu. Sergeev,
V. M. Timokhin, R. Burhenn and W7-AS Team: Observation
of Dust Production Mode During Carbon Pellet Ablation in
W7-AS Stellarator. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-1.205.
Lebedev, S. V., F. Ryter, H.-U. Fahrbach, V. E. Golant, W. Suttrop,
H. Zohm and ASDEX Upgrade Team: L-H transition at Low
Densities in ASDEX Upgrade. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-4.134.
Lang, P. T., J. Bucalossi, A. Degeling, O. Gruber, G. Haas,
L. D. Horton, J. Lister, S. Kalvin, M. Kaufmann, G. Kocsis,
Y. Martin, P. J. McCarthy, V. Mertens, R. Neu, J. Neuhauser,
T. Pütterich, W. Schneider, C. Sihler, A. C. C. Sips,
W. Suttrop, W. Treutterer and ASDEX Upgrade Team: ELM
pace making and amelioration at ASDEX Upgrade. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-4.135.
Ledl, L., R. Burhenn, L. Lengyel, F. Wagner, W7-AS Team, ECRH
Group, V. Yu. Sergeev, V. M. Timokhin, B. V. Kuteev, V. G. Skokov
and S. M. Egorov: Study of carbon pellet ablation in ECRheated W7-AS plasmas. Nuclear Fusion 44, 600-608 (2004).
Leuterer, F., G. Grünwald, F. Monaco, M. Münich, F. Ryter,
H. Schütz, D. Wagner, H. Zohm, T. Franke, G. Dammertz,
H. Heidinger, K. Koppenburg, M. Thumm, W. Kasparek,
G. Gantenbein, G. G. Denisov, A. Litvak and V. Zapevalov:
Progress in the new ECRH system for ASDEX Upgrade.
Lang, P. T., G. D. Conway, T. Eich, L. Fattorini, O. Gruber,
S. Günter, L. D. Horton, S. Kalvin, A. Kallenbach,
128
Publications and Conference Reports
Conference Digest of the 2004 Joint 29th International
Conference on Infrared and Millimeter Waves and 12th
International Conference on Terahertz Electronics, Karlsruhe 2004, (Eds.) M. Thumm, W. Wiesbeck. University of
Karlsruhe (TH), Karlsruhe (2004) 219-220, Tu3.2.
Loarte, A., G. Saibene, R. Sartori, T. Eich, A. Kallenbach,
W. Suttrop, M. Kempenaars, M. Beurskens, M. de Baar,
J. Lönnroth, P. J. Lomas, G. Matthews, W. Fundamenski,
V. Parail, M. Becoulet, P. Monier-Garbet, E. de la Luna,
B. Gonalves, C. Silva, Y. Corre and Contributors to the EFDAJET Workprogramme: Characterization of pedestal parameters and edge localized mode energy losses in the Joint
European Torus and predictions for the International
Thermonuclear Experimental Reactor. Physics of
Plasmas 11, 2668-2678 (2004).
Leuterer, F., K. Kirov, G. Pereverzev, E. Poli, F. Ryter and
D. Wagner: ECRH deposition profile in ASDEX Upgrade.
13th Joint Workshop on Electron Cyclotron Emission and
Electron Cyclotron Resonance Heating (EC-13), 2004-05-17
till 2004-05-20, Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/Leuterer.pdf.
Luce, T. C., M. R. Wade, J. R. Ferron, P. A. Politzer, A. W. Hyatt,
A. C. C. Sips and M. Murakami: High performance stationary
discharges in DIII-D tokamak. Physics of Plasmas 11,
2627-2636 (2004).
Levchuk, D., F. Koch, H. Maier and H. Bolt: Deuterium permeation through Eurofer and alpha-alumina coated Eurofer.
Journal of Nuclear Materials 328, 103-106 (2004).
Maaßberg, H. and C. D. Beidler: Self-Consistent Neoclassical
Transport Coefficients for Elongated Tokamaks. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.100.
Linsmeier, C., J. Luthin, K. U. Klages, A. Wiltner and
P. Goldstraß: Formation and Erosion of Carbon-Containing
Mixed Materials on Metals. Physica Scripta T111, 86-91 (2004).
Litaudon, X., E. Barbato, A. Bécoulet, E. J. Doyle, T. Fujita,
P. Gohil, F. Imbeaux, O. Sauter, G. Sips, for the International
Tokamak Physics Activity (ITPA) Group on Transport and
International Transport Barrier (ITB) Physics, J. W. Connor,
E. J. Doyle, Y. Esipchuk, T. Fujita, T. Fukuda, P. Gohil, J. Kinsey,
N. Kirneva, S. Lebedev, X. Litaudon, V. Mukhovatov, J. Rice,
E. Synakowski, K. Toi, B. Unterberg, V. Vershkov, M. Wakatani, for
the International ITB Database Working Group and the responsible officers for the ITPA collaborative experiments on the
“hybrid” and “steady-state” regimes, T. Aniel, Y. Baranov,
E. Barbato, A. Bécoulet, R. Behn, C. Bourdelle, G. Bracco,
R. V. Budny, P. Buratti, E. J. Doyle, Y. Esipchuk, B. Esposito,
S. Ide, A. R. Field, T. Fujita, T. Fukuda, P. Gohil, C. Gormezano,
C. Greenfield, M. Greenwald, T. S. Hahm, G. T. Hoang,
J. Hobirk, D. Hogeweij, S. Ide, A. Isayama, F. Imbeaux,
E. Joffrin, Y. Kamada, J. Kinsey, N. Kirneva, X. Litaudon,
T. C. Luce, M. Murakami, V. Parail, Y.-K. M. Peng, F. Ryter,
Y. Sakamoto, H. Shirai, G. Sips, E. Suzuki, E. Synakowski,
H. Takenaga, T. Takizuka, T. Tala, M. R. Wade and J. Weiland:
Status of and prospects for advanced tokamak regimes from
multi-machine comparisons using the “International Tokamak
Physics Activity” database. Plasma Physics and Controlled Fusion
46, A19-A34 (2004).
Madani, R., C. Ionita, R. Schrittwieser, G. Amarandei, P. Balan
and T. Klinger: A Laser-Heated Emissive Probe for Fusion
Applications. 31st EPS Conference on Controlled Fusion
and Plasma Physics, (Eds.) P. Norreys, H. Hutchinson. ECA
28G, European Physical Society, Geneva (2004), P-5.127.
Maggi, C. F., R. Dux, L. D. Horton, R. Neu, D. Nishijima,
T. Pütterich, A. C. C. Sips, B. Zaniol and ASDEX Upgrade Team:
Impurity Control in Improved H-mode Scenarios in ASDEX
Upgrade. 31st EPS Conference on Plasma Physics, London
2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G, European Physical Society, Geneva (2004), P-4.119.
Mahdizadeh, N., M. Ramisch, U. Stroth, C. Lechte and
B. D. Scott: Investigation of intermittency in simulated and
experimental turbulence data by wavelet analysis. Physics of
Plasmas 11, 3932-3938 (2004).
Maier, H. and ASDEX Upgrade Team: Tungsten erosion in the
baffle and outboard regions of the ITER-like ASDEX Upgrade
divertor. Journal of Nuclear Materials 335, 515-519 (2004).
Mailloux, J., C. D. Challis, K.-D. Zastrow, J. M. Adams, B. Alper,
Yu. Baranov, P. Belo, L. Bertalot, P. Beaumont, R. Buttery,
S. Conroy, E. De La Luna, P. de Vries, C. Giroud, N. C. Hawkes,
E. Joffrin, P. J. Lomas, D. C. McDonald, S. D. Pinches,
S. Sharapov, I. Voitsekhovitch and JET-EFDA Contributors:
Tritium Fuelling of JET Plasmas with Internal Transport
Barriers. 31st EPS Conference on Plasma Physics, London
2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-1.148.
Liu, Y. Q., T. C. Hender, M. Gryaznevich, D. F. Howell,
S. D. Pinches, R. J. Buttery, A. Bondeson and JET EFDA
Contributors: Modeling of Resistive Wall Mode
Experiments in JET. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004),
P-1.166.
129
Publications and Conference Reports
Manini, A., F. Ryter, C. Angioni, M. Apostoliceanu, A. G. Peeters,
J. Stober, G. Tardini, F. Leuterer, C. F. Maggi, D. Nishijima,
A. Stäbler, W. Stuttrop, D. Wagner and ASDEX Upgrade Team:
Experimental Evidence for Electron Heat Transport
Threshold in ASDEX Upgrade H-modes. 31st EPS Conference on Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-4.120.
Martin, Y. R., A. Degeling, P. T. Lang, J. B. Lister, A. C. C. Sips,
W. Suttrop, W. Treutterer and ASDEX Upgrade Team: Magnetic
ELM triggering on ASDEX Upgrade. 31st EPS Conference
on Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-4.133.
Marushchenko, N. B., H. Maaßberg, J. Geiger, H. Hartfuß
and Yu. A. Turkin: Analysis of ECCD scenarios for the W7-X
Stellarator by high-field-side ECE measurements. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.204.
Manini, A., F. Ryter, C. Angioni, A. G. Peeters, J. Stober,
G. Tardini, M. Apostoliceanu, F. Leuterer, C. F. Maggi,
D. Nishijima, A. Stäbler, W. Suttrop, D. Wagner and ASDEX
Upgrade Team: Experimental study of electron heat transport
in ion heated H-modes in ASDEX Upgrade. Plasma Physics
and Controlled Fusion 46, 1723-1743 (2004).
Marushchenko, N. B., H. Maaßberg, H. Hartfuß and
A. Dinklage: On non-local effects of ECE measurements at
W7-AS. 13th Joint Workshop on Electron Cyclotron
Emission and Electron Cyclotron Resonance Heating
(EC-13), 2004-05-17 till 2004-05-20, Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/marushchenko.pdf.
Mantica, P., F. Imbeaux, M. Mantsinen, D. Van Eester,
A. Marioni, N. Hawkes, E. Joffrin, V. Kiptily, S. Pinches,
A. Salmi, S. Sharapov, I. Voitsekhovitc, P. De Vries,
K.-D. Zastrow and JET EFDA Contributors: Power modulation
experiments in JET ITB plasmas. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society, Geneva
(2004), P-1.154.
Matyash, K. and R. Schneider: Kinetic modelling of dusty
plasmas. Contributions to Plasma Physics 44, 157-161 (2004).
Matyash, K. and R. Schneider: PIC-MCC modeling of a
Capacitive RF discharge. Contributions to Plasma Physics
44, 589-593 (2004).
Mantsinen, M., M.-L. Mayoral, D. VanEester, B. Alper,
R. Barnsley, P. Beaumont, J. Bucalossi, I. Coffey, S. Conroy,
M. deBaar, P. deVries, K. Erents, A. Figueiredo, A. Gondhalekar,
C. Gowers, T. Hellsten, E. Joffrin, V. Kiptily, P. Lamalle,
K. Lawson, A. Lyssoivan, J. Mailloux, P. Mantica, F. Meo,
F. Milani, I. Monakhov, A. Murari, F. Nguyen, J.-M. Noterdaeme,
J. Ongena, Yu. Petrov, E. Rachlew, V. Riccardo, E. Righi,
R. F. Rimini, M. Stamp, A. A. Tuccillo, K.-D. Zastrow, M. Zerbini
and JET-EFDA Contributors: Localized Bulk Electron
Heating with ICRF Mode Conversion in the JET Tokamak.
Nuclear Fusion 44, 33-46 (2004).
Mayer, M., V. Rohde, T. Pütterich, P. Coad, P. Wienhold, JETEFDA Contributors and ASDEX Upgrade Team: Carbon
Erosion and Migration in Fusion Devices. Physica Scripta
T111, 55-61 (2004).
Mayoral, M.-L., R. Buttery, T. T. C. Jones, V. Kiptily,
S. Sharapov, M. J. Mantsinen, S. Coda, O. Sauter,
L.-G. Eriksson, F. Nguyen, D. N. Borba, A. Mück,
S. D. Pinches, J.-M. Noterdaeme and JET-EFDA Contributors:
Studies of burning plasma physics in the Joint European
Torus. Physics of Plasmas 11, 2607-2615 (2004).
Maraschek, M., R. J. Buttery, S. Günter, D. F. Howell, R. J. La
Haye, P. T. Lang, O. Sauter, H. Zohm, ASDEX Upgrade Team
and Contributors to the EFDA-JET Workprogramme: Scaling
of the marginal βp‚of the (2/1) neoclassical tearing mode
and NTM onset conditions with extreme profiles in ASDEX
Upgrade, DIII-D and JET. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004),
P-4.128.
McDonald, D. C., J. G. Cordey, E. Righi, F. Ryter, G. Saibene,
R. Sartori, B. Alper, M. Becoulet, J. Brzozowski, I. Coffey,
M. De Baar, P. De Vries, K. Erents, W. Fundamenski,
C. Giroud, I. Jenkins, A. Loarte, P. J. Lomas, G. P. Maddison,
J. Mailloux, A. Murari, J. Ongena, J. Rapp, R. A. Pitts,
M. Stamp, J. Strachan, W. Suttrop and JET EFDA
Contributors: ELMy H-modes in JET helium-4 plasmas.
Plasma Physics and Controlled Fusion 46, 519-534 (2004).
Marburger, S. P., O. Kugeler and U. Hergenhahn: A Molecular
Beam Source for Electron Spectroscopy of Clusters.
Synchrotron Radiation Instrumentation: Eighth International
Conference, San Francisco, CA 2003, (Eds.) T. Warwick,
J. Arthur. AIP Conference Proceedings 705, American Institute
of Physics, Melville, NY (2004), 1114-1117.
McTaggart, N., X. Bonnin, A. Runov, R. Schneider and
R. Zagorski: Energy transport modelling including ergodic
effects. Contributions to Plasma Physics 44, 31-34 (2004).
130
Publications and Conference Reports
McTaggart, N., R. Zagorski, X. Bonnin, A. Runov and
R. Schneider: Finite difference scheme for solving general
3D convection-diffusion equation. Computer Physics Communication 164, 318-329 (2004).
C. Nührenberg, J. Nührenberg, M. A. Samitov, V. D. Shafranov,
A. A. Skovoroda, A. A. Subbotin, K. Yamazaki and R. Zille:
Comparison of the Properties of Quasi-Isodynamic
Configurations for Different Numbers of Periods. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-4.166.
Meister, H., R. Fischer, L. D. Horton, C. F. Maggi,
D. Nishijima, ASDEX Upgrade Team, C. Giroud, K.-D.
Zastrow, JET-EFDA Contributors and B. Zaniol: Zeff from
spectroscopic bremsstrahlung measurements at ASDEX
Upgrade and JET. Review of Scientific Instruments 75, 40974099 (2004).
Milch, I.: Fusion nucléaire – Etat et perspectives. Énergie
Panorama. Bulletin Bimensuel d’Economie nergétique 476,
5-6 (2004).
Merkel, P., C. Nührenberg and E. Strumberger: Resistive
Wall Modes of 3D Equilibria with Multiply-connected
Walls. 31st EPS Conference on Plasma Physics, London
2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-1.208.
Milch, I.: Kernfusion: Energiequelle der Zukunft? mesh.
Magazin für Wissens- und Informationsdiskurs, 11-13 (2004).
Milch, I.: Die Kraft der Sonne nachahmen. In Greifswald
nimmt das Experiment Wendelstein 7-X Konturen an.
VDI-Nachrichten 24, 3 (2004).
Merrifield, J. A., S. C. Chapman, R. O. Dendy and
W.-C. Müller: Characterising the Scaling Properties of
Incompressible Isotropic Three-Dimensional MHD
Turbulence. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-1.107.
Milch, I.: Treffpunkt Garching. Die Fusionsanlage ASDEX
Upgrade – ein europäisches Forschungsinstrument. Brains
and Tools. Helmholtz-Jahresheft, 21-24 (2004).
Miners, J. H., P. Gardner, A. M. Bradshaw and D. P. Woodruff:
A CO2 surface molecular precursor during CO oxidation
over Pt{100}. Journal of Physical Chemistry B 108, 1427014275 (2004).
Meyer-Spasche, R.: Mathematikerinnen an der Technischen
Universität München. Mitteilungen 2004/2 der TU München
für Studierende, Mitarbeiter, Freunde. KontaktTUM 4,
14-15 (2004).
Miners, J. H., P. Gardner, A. M. Bradshaw and D. P. Woodruff:
A real-time vibrational spectroscopic investigation of the
low temperature oscillatory regime of the reaction of NO
with CO on Pt{100}. Journal of Physical Chemistry B 108,
1708-1718 (2004).
Michel, G.: Synthesis of YETI-Footprint-Mirrors with Low
Stray Radiation. 13th Joint Workshop on Electron Cyclotron
Emission and Electron Cyclotron Resonance Heating
(EC-13), 2004-05-17 till 2004-05-20, Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/michel.pdf.
Mishchenko, A., R. Hatzky and A. Könies: Conventional
δ-particle simulations of electromagnetic perturbations with
finite elements. Physics of Plasmas 11, 5480-5486 (2004).
Michelsen, S., H. Bindslev, J. Egedal, J. A. Hoekzema,
S. B. Korsholm, F. Leuterer, F. Meo, P. K. Michelsen,
S. K. Nielsen, E. L. Tsakadze, E. Westerhof and P. Woskov: Fast
Ion Millimeter Wave CTS Diagnostics on TEXTOR and
ASDEX Upgrade. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-1.131.
Möller, R. and A. Könies: Coupled Principal Component
Analysis. IEEE Transactions on Neural Networks 15,
214-222 (2004).
Morozov, D. K., V. I. Gervids, I. Yu. Senichenkov, I. Yu.
Veselova, V. A. Rozhansky and R. Schneider: Ionizationrecombination processes and ablation cloud structure for a
carbon pellet. Nuclear Fusion 44, 252-259 (2004).
Michelsen, S., S. B. Korsholm, H. Bindslev, F. Meo,
P. K. Michelsen, E. L. Tsakadze, J. Egedal, P. Woskov,
J. A. Hoekzema, F. Leuterer and E. Westerhof: Fast ion millimeter wave collective Thomson scattering diagnostics on
TEXTOR and ASDEX upgrades. Review of Scientific
Instruments 75, 3634-3636 (2004).
Müller, W.-C. and R. Grappin: The residual energy in freely
decaying magnetohydrodynamic turbulence. Plasma Physics
and Controlled Fusion 46, B91-B96 (2004).
Murakami, H., H. Yamada, M. Sasao, M. Isobe, T. Ozaki,
T. Saida, P. Goncharov, J. F. Lyon, T. Seki, Y. Takeiri, Y. Oka,
Mikhailov, M. M., W. A. Cooper, M. F. Heyn, M. Yu. Isaev,
V. N. Kalyuzhnyj, S. V. Kasilov, W. Kernbichler, V. V. Nemov,
131
Publications and Conference Reports
K. Tunori, K. Ikeda, T. Mutih, K. Saito, Y. Torii, T. Watari,
A. Wasaksa, K. Y. Watanabe, H. Funaba, M. Yokoyama,
H. Maassberg, C. D. Beidler, A. Fukuyama, K. Itoh,
K. Ohkubo, O. Kaneko, A. Komori and O. Motojiama: Effect
of Neoclassical Transport Optimization on Energetic Ion
Confinement in LHD. Fusion Science and Technology 46,
241-247 (2004).
Nishijima, D., A. Kallenbach, S. Günter, M. Kaufmann,
K. Lackner, C. F. Maggi, A. Peeters, G. Pereverzev, B. Zaniol
and ASDEX Upgrade Team: Experimental studies on toroidal
plasma rotation in ASDEX Upgrade. 31 st EPS Conference
on Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-4.121.
Na, Y.-S., A. C. C. Sips, E. Joffrin, A. Stäbler, G. Tardini,
ASDEX Upgrade Team and EFDA-JET Contributors:
Transport in Improved H-mode at ASDEX Upgrade and
Comparison to JET. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-4.125.
Nishijima, D., A. Kallenbach, S. Günter, M. Kaufmann,
K. Lackner, C. F. Maggi, A. Peeters, G. Pereverzev, B. Zaniol
and ASDEX Upgrade Team: Experimental Studies on
Toroidal Plasma Rotation in ASDEX Upgrade. Plasma
Physics and Controlled Fusion 47, 89-115 (2004).
Nishijima, D., M. Y. Ye, N. Ohno and S. Takamura: Formation
mechanism of bubbles and holes on tungsten surface with
low-energy and high-flux helium plasma irradiation in
NAGDIS-II. Journal of Nuclear Materials 329-333,
1029-1033 (2004).
Naujoks, D., W. Bohmeyer, A. Markin, I. Arkhipov, P. Carl,
B. Koch, H.-D. Reiner, D. Schröder and G. Fussmann:
Transport and Deposition of Hydrocarbons in the Plasma
Generator PSI-2. Physica Scripta T111, 80-85 (2004).
Nave, M. F. F., S. Coda, R. Galvao, J. Graves, R. Koslowski,
M. Mantsinen, F. Nabais, S. Sharapov, P. de Vries, R. Buttery,
M. de Baar, C. Challis, J. Ferreira, C. Giroud, M. Mayoral,
S. D. Pinches, M. Stamp and JET-EFDA Contributors: Small
sawtooth regimes in JET plasmas. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-1.162.
Nishimura, Y., K. Borrass, D. Coster and B. Scott: Effects of
resistive drift wave turbulence on tokamak edge transport.
Contributions to Plasma Physics 44, 194-199 (2004).
Nishimura, Y., D. Coster and B. Scott: Characterization of
electrostatic turbulent fluxes in tokamak edge plasmas.
Physics of Plasmas 11, 115-124 (2004).
Nunes, I., G.D. Conway, A. Loarte, M. Manso, F. Serra,
W. Suttrop, CFN Team and ASDEX Upgrade Team:
Characterization of the density profile collapse of type I
ELMs in ASDEX Upgrade with high temporal and spatial
resolution reflectometry. Nuclear Fusion 44, 883-891
(2004).
Nemov, V. V., V. N. Kalyuzhnyj, S. V. Kasilov, M. Drevlak,
C. Nührenberg, W. Kernbichler, A. Reiman and D. Monticello:
Study of neoclassical transport and bootstrap current for
W7-X in the 1/ν- regime, using results from the PIES code.
Plasma Physics and Controlled Fusion 46, 179-191 (2004).
Neu, R.: Wolfram – die Zeiten ändern sich. IPP-Impulse 2,
6-8 (2004).
Nunes, I., L. D. Horton, A. Loarte, G. D. Conway, F. Serra,
M. Manso, CFN Team and ASDEX Upgrade Team: Study of
the Density Pedestal Width in ASDEX Upgrade using
Reflectometry. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-4.137.
Neu, R., R. Dux, A. Kallenbach, T. Eich, A. Herrmann,
C. Maggi, H. Maier, H. W. Müller, R. Pugno, T. Pütterich,
I. Radivojovic, V. Rohde and ASDEX Upgrade Team:
Operation with the new tungsten divertor: ASDEX Upgrade
en route to an all tungsten device. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-4.116.
Nührenberg, C. and A. H. Boozer: Island compensation coils
in W7-X. 31st EPS Conference on Plasma Physics, London
2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-1.202.
Neuber, D. R., R. Fischer and W. von der Linden: Data analysis
for quantum Monte Carlo simulations. Bayesian Inference
and Maximum Entrop Methods in Science and Engineering,
Garching 2004, (Eds.) R. Fischer, R. Preuss, U. von
Toussaint. AIP Conference Proceedings 735, American
Institute of Physics, Melville, NY (2004), 245-251.
Öhrwall, G., M. Tchaplyguine, M. Lundwall, R. Feifel,
H. Bergersen, T. Rander, A. Lindblad, J. Schulz, S. Peredkov,
S. Barth, S. Marburger, U. Hergenhahn, S. Svensson and
O. Björneholm: Femtosecond Interatomic Coulombic Decay
in Free Neon Clusters: Large Lifetime Differences between
Surface and Bulk. Physical Review Letters 93, 173401 (2004).
132
Publications and Conference Reports
Ongena, J., P. Monier-Garbet, W. Suttrop, Ph. Andrew,
M. Bécoulet, R. Budny, Y. Corre, G. Cordey, P. Dumortier,
T. Eich, L. Garzotti, D. L. Hillis, J. Hogan, L. C. Ingesson,
S. Jachmich, E. Joffrin, P. Lang, A. Loarte, P. Lomas,
G. P. Maddison, D. McDonald, A. Messiaen, M. F. F. Nave,
G. Saibene, R. Sartori, O. Sauter, J. D. Strachan, B. Unterberg,
M. Valovic, I. Voitsekhovitch, M. von Hellermann, B. Alper,
Y. Baranov, M. Beurskens, G. Bonheure, J. Brzozowski,
J. Bucalossi, M. Brix, M. Charlet, I. Coffey, M. De Baar,
P. De Vries, C. Giroud, C. Gowers, N. Hawkes, G. L. Jackson,
C. Jupen, A. Kallenbach, H. R. Koslowski, K. D. Lawson,
M. Mantsinen, G. Matthews, F. Milani, M. Murakami,
A. Murari, R. Neu, V. Parail, S. Podda, M. E. Puiatti, J. Rapp,
E. Righi, F. Sartori, Y. Sarazin, A. Staebler, M. Stamp,
G. Telesca, M. Valisa, B. Weyssow, K. D. Zastrow and EFDAJET Workprogramme Contributors: Towards the realization
on JET of an integrated H-mode scenario for ITER. Nuclear
Fusion 44, 124-133 (2004).
Washboard modes as ELM-related events in JET. Plasma
Physics and Controlled Fusion 46, 61-87 (2004).
Pfirsch, D. and D. Correa-Restrepo: New method of deriving local energy- and momentum-conserving Maxwell-collisionless drift-kinetic and gyrokinetic theories: basic theory.
Journal of Plasma Physics 70, 719-755 (2004).
Pinches, S. D., H. L. Berk, D. N. Borba, B. N. Breizman,
S. Briguglio, A. Fasoli, G. Fogaccia, M. P. Gryaznevich,
V. Kiptily, M. J. Mantsinen, S. E. Sharapov, D. Testa,
R. G. L. Vann, G. Vlad, F. Zonca and JET-EFDA Contributors:
The role of energetic particles in fusion plasmas. Plasma
Physics and Controlled Fusion 46, B187-B200 (2004).
Pinches, S. D., H. L. Berk, M. P. Gryaznevich, S. E. Sharapov
and JET-EFDA Contributors: Spectroscopic determination
of the internal amplitude of frequency sweeping TAE.
Plasma Physics and Controlled Fusion 46, S47-S58 (2004).
Ordás, N., C. García-Rosales, S. Lindig, M. Balden and
H. Wang: Effect of Catalytic Graphitization on the ThermoMechanical Properties of Isotropic Graphite Doped with
Metallic Carbides. Physica Scripta T111, 190-194 (2004).
Piosczyk, B., A. Arnold, E. Borie, G. Dammertz, O. Dumbrajs,
R. Heidinger, S. Illy, J. Jin, K. Koppenburg, G. Michel,
T. Rzesnicki, M. Thumm and X. Yang: Development of
Advanced High Power Gyrotrons for EC H&CD
Applications in Fusion Plasmas. 13th Joint Workshop on
Electron Cyclotron Emission and Electron Cyclotron
Resonance Heating (EC-13), 2004-05-17 till 2004-05-20,
Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/Piosczyk.pdf.
Otte, M., J. Chung, K. Horvath, J. Lingertat, Y. Podoba,
F. Wagner and D. Zhang: Overview of Recent Results from
WEGA Stellarator. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-1.211.
Pacher, G. W., H. D. Pacher, G. Janeschitz, A. S. Kukushkin
and G. Pereverzev: Operating window of ITER from consistent core-pedestal-SOL modelling with modified MMM
transport and carbon. Plasma Physics and Controlled Fusion
46, A257-A264 (2004).
Piosczyk, B., A. Arnold, H. Budig, G. Dammertz, S. Illy,
J. Jin, T. Rzesnicki, M. Thumm, O. Dumbrajs, G. Michel and
D. Wagner: 2 MW, CW, 170 GHz coaxial cavity gyrotron.
Displays and Vacuum Electronics: Proceedings, GarmischPartenkirchen 2004, (Ed.) J. Mitterauer. ITG-Fachbericht
183, VDE-Verl., Berlin (2004), 45-50.
Pautasso, G., T. Eich, A. Herrmann, D. Coster, C. Konz,
O. Gruber, K. Lackner, W. Schneider and ASDEX Upgrade
Team: Details of power deposition in the thermal quench of
ASDEX Upgrade disruptions. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-4.132.
Piosczyk, B., T. Rzesnicki, A. Arnold, H. Budig,
G. Dammertz, O. Dumbrajs, S. Illy, J. Jin, K. Koppenburg,
W. Leonhardt, G. Michel, M. Schmid, M. Thumm and
X. Yang: Progress in the development of the 170 GHz coaxial cavity gyrotron. 2004 Conference Digest of the Joint 29th
International Conference on Infrared and Millimeter Waves
and 12th International Conference on Terahertz Electronics,
Karlsruhe 2004, (Eds.) M. Thumm, W. Wiesbeck. University
of Karlsruhe (TH), Karslruhe (2004), 107-108, M4.1.
Peeters, A.G. and D. Strinzi: The effect of a uniform radial
electric field on the toroidal ion temperature gradients
mode. Physics of Plasmas 11, 3748-3751 (2004).
Poulipoulis, G., G. N. Throumoulopoulos and H. Tasso:
Tokamak MHD equilibria with reversed magnetic shear and
sheared flow. Plasma Physics and Controlled Fusion 46,
639-651 (2004).
Perez, C. P., H. R. Koslowski, T. C. Hender, P. Smeulders,
A. Loarte, P. J. Lomas, G. Saibene, R. Sartori, M. Becoulet,
T. Eich, R. J. Hastie, G. T. A. Huysmans, S. Jachmich,
A. Rogister, F. C. Schueller and JET-EFDA Contributors:
133
Publications and Conference Reports
Preuss, R., M. Daghofer and V. Dose: Modeling Energy
Confinement in Plasma Devices by Neural Networks.
Bayesian Inference and Maximum Entropy Methods in
Science and Engineering, Garching 2004, (Eds.) R. Fischer,
R. Preuss, U. von Toussaint. AIP Conference Proceedings
735, American Institute of Physics, Melville, NY (2004),
363-370.
Reetz, J., P. Heimann, S. Heinzel, Ch. Hennig, H. Kroiss,
G. Kühner, H. Kühntopf, J. Maier and M. Zilker: Image data
acquisition in the scope of long duration discharges. Fusion
Engineering and Design 71, 231-237 (2004).
Reich, M., E. Wolfrum, L. D. Horton, J. Schweinzer, J. Neuhauser
and ASDEX Upgrade Team: Edge ion temperature measurements at ASDEX Upgrade. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004),
P-4.118.
Pütterich, T., R. Neu, A. Kallenbach, Ch. Fuchs,
M. O’Mullane, A. Whiteford, H. P. Summers and ASDEX
Upgrade Team: Atomic Data for Tungsten in Fusion Devices.
31st EPS Conference on Plasma Physics, London 2004,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European
Physical Society, Geneva (2004), P-4.136.
Reich, M., E. Wolfrum, J. Schweinzer, H. Ehmler, L. D. Horton,
J. Neuhauser and ASDEX Upgrade Team: Lithium beam
charge exchange diagnostic for edge ion temperature measurements at the ASDEX Upgrade tokamak. Plasma Physics
and Controlled Fusion 46, 797-808 (2004).
Quigley, E. D., P. J. McCarthy, A. G. Peeters,
M. Apostoliceanu, J. Hobirk, V. Igochine, H. Meister, F. Ryter
and ASDEX Upgrade Team: Formation and Sustainment of
Internal Transport Barriers in ASDEX Upgrade. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-4.126.
Reimerdes, H., M. Bigi, M. S. Chu, A. M. Garofalo,
M. P. Gryaznevich, T. C. Hender, G. L. Jackson, R. J. La Haye, G.
A. Navratil, M. Okabayashi, S. D. Pinches, J. T. Scoville and E. J.
Strait: Active MHD Spectroscopy on the Resistive Wall Mode in
DIII-D and JET. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-2.184.
Quigley, E. D., A. G. Peeters, P. J. Mc Carthy,
M. Apostoliceanu, J. Hobirk, V. Igochine, H. Meister and
ASDEX Upgrade Team: Formation criteria and positioning
of internal transport barriers in ASDEX Upgrade. Nuclear
Fusion 44, 1189-1196 (2004).
Ribeiro, T., B. Scott, D. Coster and F. Serra: Tokamak turbulence computations on closed and open magnetic field lines.
31st EPS Conference on Plasma Physics, London 2004,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European
Physical Society, Geneva (2004), P-5.183.
Radtke, R., C. Biedermann, P. Bachmann, G. Fussmann and
T. Windisch: Sawtooth Oscillations in EBIT. Journal of
Physics: Conference Series 2, 84-93 (2004).
Riemann, J., M. Borchardt, R. Schneider, A. Mutzke,
T. Rognlien and M. Umansky: Navier-Stokes Neutral and
Plasma Fluid Modelling in 3D. Contributions to Plasma
Physics 44, 35-38 (2004).
Ramasubramanian, N., R. König, Y. Feng, L. Giannone,
P. Grigull, T. Klinger, K. McCormick, H. Thomsen, U. Wenzel
and W7-AS Team: Characterisation of the island divertor plasma of W7-AS stellarator in the deeply detached state with volume recombination. Nuclear Fusion 44, 992-998 (2004).
Rohde, V., R. Dux, M. Mayer, R. Neu, T. Pütterich, W. Schneider
and ASDEX Upgrade Team: Material Transport in ASDEX
Upgrade. Physica Scripta T111, 49-54 (2004).
Rapp, J., P. Monier-Garbet, G. F. Matthews, R. Sartori,
P. Andrew, P. Dumortier, T. Eich, W. Fundamenski,
M. von Hellermann, J. Hogan, L. C. Ingesson, S. Jachmich,
H. R. Koslowski, A. Loarte, G. Maddison, D. C. McDonald,
A. Messiaen, J. Ongena, V. Parail, V. Philipps, G. Saibene,
B. Unterberg and JET EFDA Contributors: Reduction of
divertor heat load in JET ELMy H-modes using impurity
seeding techniques. Nuclear Fusion 44, 312-319 (2004).
Roth, J. and C. Hopf: Sticking coefficient and surface loss
probability of eroded species during bombardment of carbon with deuterium. Journal of Nuclear Materials 334,
97-103 (2004).
Roth, J., R. Preuss, W. Bohmeyer, S. Brezinsek, A. Cambe,
E. Casarotto, R. Doerner, E. Gauthier, G. Federici,
S. Higashijima, J. Hogan, A. Kallenbach, A. Kirschner,
H. Kubo, J. M. Layet, T. Nakano, V. Philipps, A. Pospieszczyk,
R. Pugno, R. Ruggieri, B. Schweer, G. Sergienko and
M. Stamp: Flux dependence of carbon chemical erosion by
deuterium ions. Nuclear Fusion 44, L21-L25 (2004).
Raupp, G., K. Behler, R. Cole, K. Engelhardt, A. Lohs,
K. Lüddecke, G. Neu, W. Treutterer, T. Vijverberg, D. Zasche,
T. Zehetbauer and ASDEX Upgrade Team: Replacement
strategy for ASDEX upgrade’s new control and data acquisition. Fusion Engineering and Design 71, 41-45 (2004).
134
Publications and Conference Reports
Rozhansky, V., E. Kaveeva, S. Voskoboynikov, D. Coster,
X. Bonnin and R. Schneider: Simulation of ASDEX Upgrade
Edge Plasma in the H-Regime. Contributions to Plasma
Physics 44, 200-202 (2004).
J.-M. Noterdaeme, D. Testa and EFDA JET Contributors:
JET Experiments to Assess Finite Larmor Radius Effects on
Resonant Ion Energy Distribution during ICRF Heating. 31st
EPS Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-5.167.
Rozhansky, V., E. Kaveeva, S. Voskoboynikov, G. Counsell,
A. Kirk, D. Coster and R. Schneider: Simulation of
Neoclassical Effects with B2SOLPS5.0 for MAST. 31st EPS
Conference on Controlled Fusion and Plasma Physics,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European
Physical Society, Geneva (2004), P-4.198.
Santos, J., S. Hacquin, M. Manso and ASDEX Upgrade Team:
Frequency modulation continuous wave reflectometry measurements of plasma position in ASDEX Upgrade ELMy
H-mode regimes. Review of Scientific Instruments 75,
3855-3858 (2004).
Rozhansky, V., I. Senichenkov, I. Y. Veselova and R. Schneider:
Mass Deposition after Pellet Injection into a Tokamak.
Plasma Physics and Controlled Fusion 46, 575-591 (2004).
Sartori, R., G. Saibene, L. D. Horton, M. Becoulet, R. Budny,
D. Borba, A. Chankin, G. D. Conway, G. Cordey,
D. McDonald, K. Guenther, M. G. von Hellermann,
Y. Igithkanov, A. Loarte, P. J. Lomas, O. Pogutse and J. Rapp:
Study of Type III ELMs in JET. Plasma Physics and
Controlled Fusion 46, 723-750 (2004).
Rummel, T., H. Viebke, T. Bräuer, J. Kißlinger and K. Riße:
Accuracy of the construction of the superconducting coils
for Wendelstein 7-X. IEEE Transactions on Applied
Superconductivity 14, 1394-1398 (2004).
Schirmer, J., G. D. Conway, W. Suttrop, S. Klenge, H. Zohm
and ASDEX Upgrade Team: Plasma turbulence studies using
correlation Doppler reflectometry on the ASDEX Upgrade
tokamak. Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and
12th International Conference on Terahertz Electronics,
Karlsruhe 2004, (Eds.) M. Thumm, W. Wiesbeck. University
of Karlsruhe (TH), Karlsruhe (2004) 707-708, P2.56.
Runov, A., S. V. Kasilov, N. McTaggart, R. Schneider, X. Bonnin,
R. Zagorski and D. Reiter: Transport modelling for ergodic
configurations. Nuclear Fusion 44, 74-82 (2004).
Runov, A., S. Kasilov, R. Schneider and D. Reiter: Extensions of the 3-Dimensional Plasma Transport Code E3D.
Contributions to Plasma Physics 44, 18-24 (2004).
Saarelma, S. and S. Günter: Edge stability analysis of high β
plasmas. Plasma Physics and Controlled Fusion 46, 12591270 (2004).
Schirmer, J., G. D. Conway, W. Suttrop, H. Zohm and ASDEX
Upgrade Team: Radial Electric Field Shear and Correlation
Length Measurements in ASDEX Upgrade using
Correlation Doppler Reflectometry. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys,
H. Hutchinson. ECA 28G, European Physical Society,
Geneva (2004), P-4.127.
Saibene, G., T. Hatae, D. J. Campbell, J. G. Cordey,
E. de la Luna, C. Giroud, K. Guenther, Y. Kamda,
M. A. H. Kempenaars, A. Loarte, J. Lönnroth, D. Mc Donald,
M. F. F. Nave, N. Oyama, V. Parail, R. Sartori, J. Stober,
T. Suzuki, M. Takechi and K. Toi: Dimensionless pedestal identiy experiments in JT-60U and JET in ELMy H-mode. Plasma
Physics and Controlled Fusion 46, A195-A206 (2004).
Schmid, K., M. Baldwin, R. Doerner and A. Wiltner:
Influence of Beryllium plasma impurities on the erosion of
graphite. Nuclear Fusion 44, 815-819 (2004).
Saibene, G., P. J. Lomas, J. Stober, R. Sartori, A. Loarte,
F. G. Rimini, Y. Andrew, S. A. Arshad, P. Belo, M. Kempenaars,
H. R. Koslowski, J. S. Lonnroth, D. C. McDonald, A. G. Meigs,
P. Monier Garbet, M. F. F. Nave, V. Parail, C. P. Perez,
P. R. Thomas and Contributors to the EFDA-JET Workprogramme: Small ELM experiments in H-mode plasmas in
JET. 31st EPS Conference on Plasma Physics, London 2004,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European
Physical Society, Geneva (2004), O-4.02.
Schmid, K., A. Wiltner and C. Linsmeier: Measurement of
beryllium depth profiles in carbon. Nuclear Instruments and
Methods in Physics Research B 219-220, 947-952 (2004).
Salmi, A., P. Beaumont, P. de Vries, L.-G. Eriksson,
C. Gowers, P. Helander, M. Laxback, M. J. Mantsinen,
Schneider, R., X. Bonnin, N. McTaggart, A. Runov,
M. Borchardt, J. Riemann, A. Mutzke, K. Matyash, H. Leyh,
Schmidt, M., Y. Turkin and A. Werner: “Advanced”-δf Monte
Carlo Simulation of NBI current drive in W7-X. 31st EPS
Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.200.
135
Publications and Conference Reports
M. Warrier, D. Coster, W. Eckstein and R. Dohmen: Comprehensive suite of codes for plasma-edge modelling.
Computer Physics Communications 164, 9-16 (2004).
Contributors: Experiment on tritium beam evolution in JET plasmas with fishbones and TAE-modes. 31st EPS Conference on
Plasma Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004), P-5.166.
Schneider, W., V. Rohde, K. Krieger, D. Hildebrandt, R. Neu
and ASDEX Upgrade Team: Surface Layer Deposition in
ASDEX Upgrade with a Tungsten Wall as Measured by
SIMS, AES and PIXE. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004),
P-4.117.
Sorge, S.: Investigation of ITG turbulence in cylinder geometry within a gyrokinetic global PIC simulation: influence of
zonal flows and a magnetic well. Plasma Physics and
Controlled Fusion 46, 535-549 (2004).
Speth, E. and NBI-Team: Development of Powerful RF
Plasma Sources for Present and Future NBI Systems.
Plasma Science and Technology 6, 2135-2140 (2004).
Schubert, M., M. Endler and W7-AS Team: Density, Electron
Temperature and Electric Potential Fluctuations and Induced
Radial Transport in the Boundary of the Wendelstein 7-AS
Stellarator from a Poloidal Array of Langmuir Probes. 31st
EPS Conference on Plasma Physics, London 2004, (Eds.)
P. Norreys, H. Hutchinson. ECA 28G, European Physical
Society, Geneva (2004), P-1.210.
Strachan, J. D., G. Corrigan, A. Kallenbach, G. F. Matthews,
H. Meister, R. Neu, V. Rohde and J. Spence: Diverted tokamak carbon screening: scaling with machine size and consequences for core contamination. Nuclear Fusion 44, 772787 (2004).
Scott, B. and F. Porcelli: Two-dimensional fast reconnection in
a fluid drift model. Physics of Plasmas 11, 5468-5474 (2004).
Strintzi, D. and B. Scott: Nonlocal nonlinear electrostatic
gyrofluid equations. Physics of Plasmas 11, 5452-5461
(2004).
Sengupta, A., P. J. McCarthy, J. Geiger and A. Werner:
Development of Function Parametrization on W7-X stellarator. 31st EPS Conference on Plasma Physics, London 2004,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European
Physical Society, Geneva (2004), P-1.199.
Strumberger, E., S. Günter, J. Hobirk, V. Igochine, D. Merkl, E.
Schwarz, C. Tichmann and ASDEX Upgrade Team: Numerical
investigations of axisymmetric equilibria with current holes.
Nuclear Fusion 44, 464-472 (2004).
Sengupta, A., P. J. McCarthy, J. Geiger and A. Werner: Fast
recovery of vacuum magnetic configuration of W7-X stellarator using function parametrization and artifical neural
networks. Nuclear Fusion 44, 1176-1188 (2004).
Suttrop, W., G. D. Conway, L. Fattorini, L. D. Horton, T. KurkiSuonio, C. F. Maggi, M. Maraschek, H. Meister, R. Neu,
T. Pütterich, M. Reich, A. C. C. Sips and ASDEX Upgrade
Team: Study of quiescent H-mode plasmas in ASDEX
Upgrade. Plasma Physics and Controlled Fusion 46,
A151-A156 (2004).
Shafranov, V. D., W. A. Cooper, M. F. Heyn, M. Yu. Isaev,
V. N. Kalyuzhnyj, S. V. Kasilov, W. Kernbichler,
M. M. Mikhailov, V. V. Nemov, C. Nührenberg, J. Nührenberg,
M. A. Samitov, A. A. Skovoroda, A. A. Subbotin and R. Zille:
Results of Integrated Optimization of N=9 Quasi-isodynamic stellarator. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-4.167.
Svensson, J., A. Dinklage, J. Geiger, A. Werner and
R. Fischer: Integrating diagnostic data analysis for W7-AS
using Bayesian graphical models. Review of Scientific
Instruments 75, 4219-4221 (2004).
Tabarés, F. L., V. Rohde and ASDEX Upgrade Team: Plasma
processing techniques for tritium inventory control in fusion
research. Plasma Physics and Controlled Fusion 46,
B381-B395 (2004).
Sharapov, S. E., B. Alper, J. Fessey, N. C. Hawkes, N. P. Young,
R. Nazikian, G. J. Kramer, D. N. Borba, S. Hacquin, E. De La
Luna, S. D. Pinches, J. Rapp, D. Testa and JET-EFDA
Contributors: Monitoring Alfvén cascades with interferometry on the JET tokamak. Physical Review Letters 93,
165001 (2004).
Taccogna, F., S. Longo, M. Capitelli and R. Schneider:
Stationary plasma thruster simulation. Computer Physics
Communications 164, 160-170 (2004).
Sharapov, S., S. Popovichev, B. Alper, Y. F. Baranov, L. Bertalot,
D. Borba, S. Conroy, D. Howell, V. Kiptily, S. Pinches,
M. Stamp, D. Stork, I. Voitsekhovich and EFDA-JET
Taglauer, E. and R. Beikler: Surface segregation studied by
low-energy ion scattering: experiment and numerical simulation. Vacuum 73, 9-14 (2004).
136
Publications and Conference Reports
Takamura, S., N. Ohno, M. Y. Ye and T. Kuwabara: SpaceCharge Limited Current from Plasma-Facing Material
Surface. Contributions to Plasma Physics 44, 126-137 (2004).
Throumoulopoulos, G. N., K. Hizanidis and H. Tasso:
Comment on “Solitonlike solutions of the Grad-Shafranov
equation”. Physical Review Letters 92, 249501 (2004).
Tanga, A., M. Bandyopadhyay and P. McNeely: Measurement
of ion flow in a negative ion source using a Mach probe.
Applied Physics Letters 84, 182-184 (2004).
Thumm, M., A. Arnold, G. Dammertz, G. Michel,
J. Pretterebner, D. Wagner and X. Yang: Highly Efficient
Quasi-optical Mode Converter System for a 1 MW, 140 GHz,
CW Gyrotron. 13th Joint Workshop on Electron Cyclotron
Emission and Electron Cyclotron Resonance Heating (EC-13),
2004-05-17 till 2004-05-20, Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/Thumm-MC.pdf.
Tardini, G., J. Hobirk, V. G. Igochine, M. Maraschek,
A. G. Peeters, G. V. Pereverzev, A. C. C. Sips and ASDEX
Upgrade Team: ITB Collapse and ELMs in ASDEX
Upgrade. 31st EPS Conference on Plasma Physics, London
2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Scoiety, Geneva (2004), P-4.123.
Tasso, H. and G. N. Throumoulopoulos: Instability theorem
in magnetohydrodynamics revisited. Physics of Plasmas 11,
334-335 (2004).
Thumm, M., A. Arnold, G. Dammertz, G. Michel, D. Wagner
and J. Pretterebner: An advanced dimple-wall launcher for a
140 GHz 1 MW continuous wave gyrotron. Displays and
Vacuum Electronics: Proceedings, Garmisch-Partenkirchen
2004, (Ed.) J. Mitterauer. ITG-Fachbericht 183, VDE-Verl.,
Berlin (2004) 195-200.
Terry, J. L., S. J. Zweben, B. Bose, O. Grulke, E. S. Marmar,
J. Lowrance, V. Mastrocola and G. Renda: High speed movies
of turbulence in Alcator C-Mod. Review of Scientific
Instruments 75, 4196-4199 (2004).
Timokhin, V. M., B. V. Kuteev, V. Yu. Sergeev, V. G. Skokov and
R. Burhenn: Local Enhanced Evaporation of Carbon Pellets
in a Wendelstein 7-AS Stellarator. Technical Physics Letters
30, 298-300 (2004).
Thomas, D. M., M. E. Fenstermacher, D. Finkenthal,
R. J. Groebner, L. L. Lao, A. W. Leonard, H. W. Müller,
T. H. Osborne and P. B. Snyder: Edge currents and stability in
DIII-D. 31st EPS Conference on Plasma Physics, London
2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-2.177.
Timokhin, V. M., B. V. Kuteev, V. Yu. Sergeev, V. G. Skokov,
R. Burhenn and W7-AS Team: Effect of Narrow Localized
Enhanced Ablation of Carbon Pellets in Wendelstein 7-AS
Stellarartor. Pisma v Zhurnal Tekhnicheskoi Fiziki 30, 83-87
(2004).
Toi, K., S. Ohdachi, S. Yamamoto, N. Nakajima, S. Sakakibara,
K. Y. Watanabe, S. Inagaki, Y. Nagayama, Y. Narushima,
H. Yamada, K. Narihara, S. Morita, T. Akiyama, N. Ashikawa,
X. Ding, M. Emoto, H. Funaba, M. Goto, K. Ida, H. Idei,
T. Ido, K. Ikeda, S. Imagawa, M. Isobe, K. Itoh, O. Kaneko,
K. Kawahata, T. Kobuchi, A. Komori, S. Kubo, R. Kumazawa,
J. Li, Y. Liang, S. Masuzaki, T. Mito, J. Miyazawa, T. Morisaki,
S. Murakami, S. Muto, T. Mutoh, K. Nagaoka, Y. Nakamura,
H. Nakanishi, K. Nishimura, A. Nishizawa, N. Noda, T. Notake,
I. Ohtake, N. Ohyabu, Y. Oka, S. Okamura, T. Ozaki,
B. J. Peterson, A. Sagara, T. Saida, K. Saito, R. Sakamoto,
M. Sasao, K. Sato, M. Sato, T. Satow, T. Seki, T. Shimozuma,
M. Shoji, S. Sudo, M. Y. Tanaka, N. Tamura, K. Tanaka,
K. Tsumori, T. Uda, T. Watari, A. Weller, Y. Xu, I. Yamada,
Y. Yokoyama, S. Yoshimura, Y. Yoshimura, K. Yamazaki,
K. Matsuoka, I. Motojima, Y. Hamada and M. Fujiwara: MHD
instabilities and their effects on plasma confinement in
Large Helical Device plasmas. Nuclear Fusion 44,
217-225 (2004).
Thomas, D. M., A. W. Leonard, L. L. Lao, T. H. Osborne,
H. W. Müller and D. F. Finkenthal: Measurement of
Pressure-Gradient-Driven Currents in Tokamak Edge
Plasmas. Physical Review Letters 93, 065003 (2004).
Thomas, D. M., A. W. Leonard and H. W. Mueller: Calculation
of edge toroidal current density distributions from DIII-D
lithium beam measurements using Ampère’s law. Review of
Scientific Instruments 75, 4109-4111 (2004).
Thomsen, H., R. König, Y. Feng, P. Grigull, T. Klinger,
K. McCormick, N. Ramasubramanian, U. Wenzel and W7-AS
Team: Radiative condensation and detachment in Wendelstein 7-AS stellarator. Nuclear Fusion 44, 820-826 (2004).
Thomsen, K., J. G. Cordey, O. J. W. F. Kardaun and ITPA
H-mode Database Working Group: Analysis of the bias in
H-mode confinement scaling expressions related to measurement errors in variables. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004),
P-5.145.
Toussaint, U. von, V. Dose and A. Golan: Maximum entropy
decomposition of quadrupole mass spectra. Journal of
Vacuum Science and Technology A 22, 401-406 (2004).
137
Publications and Conference Reports
Toussaint, U. von, S. Gori and V. Dose: Bayesian neural-networks-based evaluation of binary speckle data. Applied
Optics 43, 5356-5363 (2004).
B. Piosczyk, B. Plaum, D. M. S. Ronden, G. Saibene and
H. Zohm: Design of the MM-Wave System of the ITER
ECRH Upper Launcher. 13th Joint Workshop on Electron
Cyclotron Emission and Electron Cyclotron Resonance
Heating (EC-13), 2004-05-17 till 2004-05-20, Nizhny
Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/verhoeven.PDF.
Toussaint, U. von, S. Gori and V. Dose: A Prior for Neural
Networks utilizing Enclosing Spheres for Normalization.
Bayesian Inference and Maximum Entropy Methods in
Science and Engineering, Garching 2004, (Eds.) R. Fischer,
R. Preuss, U. von Toussaint. AIP Conference Proceedings 735,
American Institute of Physics, Melville, NY (2004), 328-335.
Villard, L., S. J. Allfrey, A. Bottino, M Brunetti, G. L. Falchetto,
V. Grandgirard, R. Hatzky, J. Nührenberg, A. G. Peeters,
O. Sauter, S. Sorge and J. Vaclavik: Full radius linear and nonlinear gyrokinetic simulations for tokamaks and stellarators:
zonal flows, applied ExB flows, trapped electrons and finite
beta. Nuclear Fusion 44, 172-180 (2004).
Tran, M. Q., A. Arnold, D. Bariou, E. Borie, G. Dammertz,
C. Darbos, O. Dumbrajs, G. Gantenbein, E. Giguet,
R. Heidinger, J. P. Hogge, S. Illy, W. Kasparek, C. Lievin,
R. Magne, G. Michel, B. Piosczyk, M. Thumm and
I. Yovchev: Development of high power gyrotrons for fusion
plasma applications in the EU. Conference Digest of the
Joint 29th International Conference on Infrared and
Millimeter Waves and 12th International Conference on
Terahertz Electronics, Karlsruhe 2004, (Eds.) M. Thumm,
W. Wiesbeck. University Karlsruhe (TH), Karlsruhe (2004),
59-60, PLTu.1.
Villard, L., P. Angelino, A. Bottino, S. J. Allfrey, R. Hatzky,
Y. Idomura, O. Sauter and T. M. Tran: First principles based
simulations of instabilities and turbulence. Plasma Physics
and Controlled Fusion 46, B51-B62 (2004).
Wagner, D., G. Grünwald, F. Leuterer, F. Monaco,
M. Münich, H. Schütz, F. Ryter, R. Wilhelm, H. Zohm,
T. Franke, G. Dammertz, H. Heidinger, K. Koppenburg,
M. Thumm, X. Yang, W. Kasparek, G. Gantenbein, H. Hailer,
G. G. Denisov, A. Litvak and V. Zapevalov: Status of the New
ECRH System for ASDEX Upgrade. 13th Joint Workshop on
Electron Cyclotron Emission and Electron Cyclotron
Resonance Heating (EC-13), 2004-05-17 till 2004-05-20,
Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/wagner.pdf.
Tsitrone, E., P. Andrew, X. Bonnin, P. Coad, D. Coster,
W. Fundamenski, P. Ghendrih, A. Huber, S. Jachmich,
A. Kukushkin, A. Loarte, G. Matthews, R. Pitts, J. Rapp,
D. Reiter, M. Stamp, M. Wischmeier and Contributors to the
JET EFDA Work Programme: Divertor modelling of septum
assessment experiments in JET MkIIGB. Contributions to
Plasma Physics 44, 241-246 (2004).
Turkin, Y., H. Maaßberg, C. D. Beidler, J. Geiger and
N. B. Marushchenko: Predictive transport modeling for the
W7-X. 31st EPS Conference on Plasma Physics, London
2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G, European Physical Society, Geneva (2004), P-1.198.
Wagner, D., F. Leuterer, G. Gantenbein, E. Holzhauer and
W. Kasparek: Polarizer design for multi-frequency high
power ECRH transmission lines. Conference Digest of the
2004 Joint 29th International Conference on Infrared and
Millimeter Waves and 12th International Conference on
Terahertz Electronics, Karlsruhe 2004, (Eds.) M. Thumm,
W. Wiesbeck. University of Karlsruhe (TH), Karlsruhe
(2004) 259-260, Tu7.2.
Urano, H., W. Suttrop, P. T. Lang, L. D. Horton, A. Herrmann
and ASDEX Upgrade Team: Fully pellet-controlled ELMs
sustaining identical pedestal conditions of natural ELMy
H-mode in ASDEX Upgrade. Plasma Physics and
Controlled Fusion 46, A315-A322 (2004).
Wagner, F. (Ed.): Fourteenth International Stellarator Workshop (Part 1), Greifswald, Germany, September 22-26, 2003.
Fusion Science and Technology 46, 1-223 (2004).
Valovic, M., H. Budny, L. Garzotti, X. Garbet, A. A. Korotkov,
J. Rapp, R. Neu, O. Sauter, P. de Vries, B. Alper, M. Beurskens,
J. Brzozowski, D. McDonald, H. Leggate, C. Giroud, V. Parail,
I. Voitsekhovitch and JET EFDA Contributors: Density peaking in low collisionality ELMy H-mode in JET. Plasma
Physics and Controlled Fusion 46, 1877-1889 (2004).
Wagner, F. (Ed.): Fourteenth International Stellarator Workshop (Part 2), Greifswald, Germany, September 22-26, 2003.
Fusion Science and Technology 46, 225-400 (2004).
Wanner, M., T. Andreeva, T. Bräuer and J. Kißlinger:
Accuracy of the Magnet Configuration of Wendelstein 7-X.
31st EPS Conference on Plasma Physics, London 2004,
(Eds.) P. Norreys, H. Hutchinson. ECA 28G, European
Physical Society, Geneva (2004), O-4.05.
Verhoeven, A. G. A., W. A. Bongers, A. Bruschi, S. Cirant,
B. S. Q. Elzendoorn, G. Gantenbein, M. F. Graswinckel,
R. Heidinger, W. Kasparek, O. G. Kruyt, B. Lamers,
138
Publications and Conference Reports
Wanner, M., T. Andreeva, T. Bräuer and J. Kißlinger:
Accuracy of the magnet configuration of Wendelstein 7-X.
Stellarator News 94, 6-8 (2004).
of the detachment phases in the W7-AS stellarator. Nuclear
Fusion 44, 1130-1140 (2004).
Wesson, J., D. J. Campbell, J. W. Connor, R. D. Gill, J. Hugill,
C. N. Lashmore-Davies, G. M. McCracken, H. R. Wilson,
A. E. Costley, R. J. Hastie, A. Herrmann, B. Lloyd,
G. F. Matthews, J. J. O’Rourke, D. F. Start, B. J. D. Tubbing and
D. J. Ward: Tokamaks. International Series of Monographs
on Physics 118. Clarendon Press, Oxford (2004) 749 p.
Warrier, M., R. Schneider and X. Bonnin: Subroutines for
some plasma surface interaction processes: physical sputtering, chemical erosion, radiation enhanced sublimation,
backscattering and thermal evaporation. Computer Physics
Communications 160, 46-68 (2004).
Warrier, M., R. Schneider, E. Salonen and K. Nordlund:
Modeling of the Diffusion of Hydrogen in Porous Graphite.
Physica Scripta T108, 85-89 (2004).
Wischmeier, M., R. A. Pitts, A. Alfier, Y. Andrebe, R. Behn,
D. Coster, J. Horacek, P. Nielsen, R. Pasqualotto, D. Reiter
and A. Zabolotsky: The influence of molecular dynamics on
divertor detachment in TCV. Contributions to Plasma
Physics 44, 268-273 (2004).
Warrier, M., R. Schneider, E. Salonen and K. Nordlund: Multiscale modeling of hydrogen isotope diffusion in graphite.
Contributions to Plasma Physics 44, 307-310 (2004).
Wright, J. C., P. T. Bonoli, E. D. Azevedo and M. Brambilla:
Ultrahigh resolution simulations of mode converted ion
cyclotron waves and lower hybrid waves. Computer Physics
Communications 164, 330-335 (2004).
Watanabe, K. Y., A. Weller, S. Sakakibara, Y. Narushima,
S. Ohdachi, K. Narihara, K. Tanaka, K. Ida, K. Toi, H. Yamada,
Y. Suzuki, O. Kaneko, Large Helical Device Experimental Group
and Wendelstein 7-AS Experimental Group: Progress of HighBeta Experiments in Stellarator/Heliotron. Fusion Science
and Technology 46, 24-33 (2004).
Wright, J. C., P. T. Bonoli, M. Brambilla, F. Meo,
E. D’Azevedo, D. B. Batchelor, E. F. Jaeger, L. A. Berry,
C. K. Phillips and A. Pletzer: Full wave simulations of fast
wave mode conversion and lower hybrid wave propagation
in tokamaks. Physics of Plasmas 11, 2473-2479 (2004).
Watts, C., H. J. Hartfuss and M. Häse: Comparison of different methods of electron cyclotron emission-correlation
radiometry for the measurement of temperature fluctuations
in the plasma core. Review of Scientific Instruments 75,
3177-3184 (2004).
Yamada, H., J. H. Harris, A. Dinklage, E. Ascasibar, F. Sano,
S. Okamura, U. Stroth, A. Kus, J. Talmadge, S. Murakami,
M. Yokoyama, C. D. Beidler, V. Tribaldos and K. Y. Watanabe:
Study on energy confinement time of net-current free
toroidal plasmas based on extended international stellarator
database. 31st EPS Conference on Plasma Physics, London
2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-5.099.
Weiland, J., E. Asp, X. Garbet, P. Mantica, V. Parail,
P. Thomas, W. Suttrop, T. Tala and EFDA-JET Contributors:
Effects of temperature ratio on JET transport in hot ion and
hot electron regime. 31st EPS Conference on Plasma
Physics, London 2004, (Eds.) P. Norreys, H. Hutchinson.
ECA 28G, European Physical Society, Geneva (2004),
P-1.160.
Yamada, H., J. H. Harris, A. Dinklage, E. Ascasibar, F. Sano,
S. Okamura, J. Talmadge and U. Stroth: Confinement study
based on an extended international stellarator database: An
interim report. Stellarator News 92, 6-8 (2004).
Weisen, H., A. Zabolotsky, C. Giroud, H. Leggate,
K.-D. Zastrow, C. Angioni, J. Weiland, X. Garbet, L. Zabeo,
D. Mazon, I. Furno and JET-EFDA Contributors: Shear, temperature gradient and collisionality dependences of particle
pinches in JET. 31st EPS Conference on Plasma Physics,
London 2004, (Eds.) P. Norreys, H. Hutchinson. ECA 28G,
European Physical Society, Geneva (2004), P-1.146.
Yamada, H., K. Ida, S. Murakami, K. Y. Watanabe,
E. Ascasibar, R. Brakel, A. Dinklage, J. H. Harris,
S. Okamura, F. Sano, U. Stroth, S. Inagaki, K. Tanaka,
M. Goto, K. Nishimura, K. Narihara, S. Morita,
S. Sakakibara, B. J. Peterson, R. Sakamoto, J. Miyazawa,
T. Morisaki, M. Osakabe, K. Toi, N. Tamura, K. Ikeda,
K. Yamazaki, K. Kawahata, O. Kaneko, N. Ohyabu,
A. Komori, O. Motojima and LHD Experimental Group:
Configuration Effect on Energy Confinement and Local
Transport in LHD and Contribution to the International
Stellarator Database. Fusion Science and Technology 46,
82-90 (2004).
Weller, A., S. Mohr and C. Junghans: Concepts of x-ray diagnostics for WENDELSTEIN 7-X. Review of Scientific
Instruments 75, 3962-3965 (2004).
Wenzel, U., K. McCormick, N. Ramasubramanian,
F. Gadelmeier, P. Grigull, R. König and H. Thomsen: Study
139
Publications and Conference Reports
Yoshinuma, M., K. Ida and J. Baldzuhn: Charge exchange
spectroscopy by Fabry-Pérot spectrometer in W7-AS.
Review of Scientific Instruments 75, 4136-4138 (2004).
and E. Westerhof: The ITER ECRH Upper Launcher – Physics
Goals and Design Requirements. 13th Joint Workshop on Electron
Cyclotron Emission and Electron Cyclotron Resonance Heating
(EC-13), 2004-05-17 till 2004-05-20, Nizhny Novgorod, 6 p.,
http://www.ec13.iapras.ru/papers/Zohm_Contributed.pdf.
You, J.-H. and H. Bolt: Structural analysis of a plasma-facing component reinforced with fibrous metal matrix composite laminate. Journal of Nuclear Materials 329-333,
702-705 (2004).
Zurro, B., M. A. Ochando, A. Baciero, K. J. McCarthy,
F. Medina, A. López-Sánchez, D. Rapisarda, D. Jimenez,
A. Fernández, I. Pastor, J. Herranz and R. Dux: Method to
deduce local impurity transport quantities from the evolution of tomographically reconstructed bolometer signals
during tracer injection at TJ-II. Review of Scientific
Instruments 75, 4231-4233.
You, J.-H. and O. Poznansky: Dual scale non-linear stress
analysis of a fibrous metal matrix composite. Journal of
Materials Science 39, 2121-2130 (2004).
Yu, Q., S. Günter and K. Lackner: Numerical modeling of
nonlinear growth and saturation of neoclassical tearing
modes. Physics of Plasmas 11, 140-150 (2004).
Zvejnieks, G., V. N. Kuzovkov, O. Dumbrajs, A. W. Degeling,
W. Suttrop, H. Urano and H. Zohm: Autoregressive moving
average model for analyzing edge localized mode time series
on Axially Symmetric Divertor Experiment (ASDEX)
Upgrade tokamak. Physics of Plasmas 11, 5658-5667 (2004).
Yu, Q., X. D. Zhang and S. Günter: Numerical studies on the
stabilization of neoclassical tearing modes by radio frequency current drive. Physics of Plasmas 11, 1960-1968 (2004).
Zakharov, L. E., N. N. Gorelenkov, R. B. White,
S. I. Krasheninnikov and G. V. Pereverzev: Ignited sperical
tokamaks and plasma regimes with LiWalls. Fusion
Engineering and Design 72, 149-168 (2004).
Zastrow, K.-D., J. M. Adams, Y. Baranov, P. Belo, L. Bertalot,
H. J. Brzozowski, C. D. Challis, S. Conroy, M. de Baar,
P. de Vries, P. Dumortier, J. Ferreira, L. Garzotti,
T. C. Hender, E. Joffrin, V. Kiptily, J. Mailloux,
D. C. McDonald, R. Neu, M. O’Mullane, M. F. F. Nave,
J. Ongena, S. Popovichev, M. Stamp, J. Stober, D. Stork,
I. Voitsekhovitch, M. Valovic, H. Weisen, A. D. Whiteford,
A. Zabolotsky and JET EFDA Contributors: Tritium transport experiments on the JET tokamak. Plasma Physics and
Controlled Fusion 46, B255 -B265 (2004).
Zohm, H.: The concept of ECRH/ECCD for ITER. 13th Joint
Workshop on Electron Cyclotron Emission and Electron
Cyclotron Resonance Heating (EC-13), 2004-05-17 till
2004-05-20, Nizhny Novgorod, 10 p.,
http://www.ec13.iapras.ru/papers/Zohm_Invited.pdf.
Zohm, H.: Microwave heating and current drive for performance optimisation in magnetically confined fusion plasma.
Conference Digest of the 2004 Joint 29th International
Conference on Infrared and Millimeter Waves and 12th
International Conference on Terahertz Electronics,
Karlsruhe 2004, (Eds.) M. Thumm, W. Wiesbeck. University
of Karlsruhe (TH), Karlsruhe (2004) 217-218, Tu3.1.
Zohm, H., D. Farina, R. Heidinger, B. Lloyd, S. Nowak, E. Poli,
G. Ramponi, G. Saibene, O. Sauter, A. G. A. Verhoeven, F. Volpe
140
Publications and Conference Reports
Diploma Theses
Juan Pardo, M. E.: Characterisation and Mitigation of Chemical Erosion of Doped Carbon Materials. Technische Universität München 2004.
Albrecht, A.: Der Energiemarkt und dessen techno-ökonomische Modellierung – Potentiale zukünftiger Technologien.
Universität Augsburg 2004.
Koch, B.: Angular Resolved Measurements of Particle and
Energy Fluxes to Surfaces in Magnetized Plasmas.
Humboldt-Universität Berlin 2004.
Harhausen, J.: Characterisation of a multi-channel FabryPerot spectrometer and charge exchange recombination
spectroscopy in the poloidal plane of ASDEX Upgrade.
Ludwig-Maximilians-Universität München 2004.
Kornilov, V.: Global Ion-Temperature Gradient Driven
Instabilities in Stellarators within Two-Fluid and Gyrokinetic Description. Universität Greifswald 2004.
Höllt, L.: Prädiktive Simulation von Plasmaentladungen am
Fusionsexperiment ASDEX Upgrade. Ludwig-MaximiliansUniversität München 2004.
Marburger, S. P.: Experimentelle Untersuchungen zum
Interatomaren Coulomb Zerfall an Neon Clustern: Nachweis eines ultraschnellen nichtlokalen Zerfallskanals. Technische Universität Berlin 2004.
Millet, J.: Tungsten Silicide Doped with Chromium as
Plasma-facing Material for Fusion Reactor in Case of
Coolant Loss and Air Ingress: Study of High Temperature
Corrosion Resistance. Ecole Nationale Supérieure de
Chimie, Paris 2004.
Merkl, D.: “Current Holes” and other Structures in Motional
Stark Effect Measurements. Technische Universität
München 2004.
Quintana Alonso, I.: The Deposition of Metal Containing
Carbon Films and the Characterisation of these Films.
Universidad de Navarra, San Sebastian 2004.
Mück, A.: Study of the Sawtooth Instability and its Control
in the ASDEX Upgrade Tokamak. Technische Universität
München 2004.
Reich, M.: Entwurf und Implementierung von Algorithmen
zur Eindringtiefenbestimmung von kryogenen Wasserstoffpellets von Fusionsplasmen. Fachhochschule WeidenAmberg 2004.
Popescu, C.: Processing and Characterisation of SiC-Fibre
Reinforced Cu-Matrix Composites. Technische Universität
München 2004.
Richter, S.: Beschreibung und Optimierung urbaner Energiesysteme. Universität Augsburg 2004.
Schoop, S.: Erzeugung und Nachweis negativer Wasserstoffionen in einer Hohlkathoden-Plasmaquelle. Technische Universität München 2004.
Schröder, C.: Experimental investigations on drift waves in
linear magnetized plasmas. Universität Greifswald 2004.
Warrier, M.: Multi-scale modeling of hydrogen isotope
transport in porous graphite. Universität Greifswald 2004.
Doctoral Theses
Bandyopadhyay, M.: Studies of an inductively coupled negative hydrogen ion radio frequency source through simulations
and experiments. Technische Universität München 2004.
Wiltner, A.: Untersuchungen zur Diffusion und Reaktion von
Kohlenstoff auf Nickel- und Eisenoberflächen sowie von
Beryllium auf Wolfram. Universität Bayreuth 2004.
Bauer, M.: Bestimmung der Wachstumsprecursoren für
amorphe Kohlenwasserstoffschichten in gepulsten Methanplasmen. Universität Bayreuth 2004.
Habilitation
Dux, R.: Impurity Transport in Tokamak Plasmas. Universität Augsburg 2004.
Biberacher, M.: Modelling and optimisation of future energy system using spatial and temporal methods. Universität
Augsburg 2004.
Chung, J.: Development of a MOSS system for two-dimensional spectral imaging. Universität Greifswald 2004.
Horvath, K.: Characterisation and Optimisation of WEGA
Plasmas. Universität Greifswald 2004.
141
Patents
Biedermann, Ch., R. Radtke and S. Deuchler: Hochflexibler
Membranbalg mit vorgelagertem Drehpunkt. Freigabe des
deutschen sowie des europäischen Patents: 13.10.2004.
Brockmann, R.: Kaltlecksuchkammer zum Nachweis von
Leckraten. Erfindungsmeldung: 5.2.2004. Erfindung wurde
beschränkt in Anspruch genommen.
Michel, G.: Schnelles und vielseitiges Interlocksystem.
Erfindungsmeldung: 12.10.2004.
Schacht, J. and H. Niedermeyer: Verfahren und Vorrichtung
zum Synchronisieren und Steuern von technischen Systemen. Erteilung des Patents ist rechtskräftig geworden:
7.4.2004.
Schauer, F.: Abstandhalter mit extrem niedriger Wärmeleitung. Anmeldung der Erfindung und Stellung des
Prüfantrags: 11.2.2004. Aktenzeichen 10 2004 006 779.1.
Anmeldung innerhalb der Prioritätsfrist in Europa:
20.12.2004.
Schauer, F.: Prüfeinrichtung für Kaltlecks von Rohren.
Erfindungsmeldung: 2.11.2004. Erfindung wurde unbeschränkt in Anspruch genommen: 22.12.2004.
Schauer, F.: Wärmetauscherstromleiter für TieftemperaturStromzuführungen. Erfindungsmeldung: 6.10.2004. Erfindung wurde unbeschränkt in Anspruch genommen:
30.11. 2004.
Schauer, F. and M. Nagel: Thermischer Schild. Erfindungsmeldung: 26.4.2004. Erfindung wurde unbeschränkt in Anspruch genommen: 28.4.2004. Anmeldung der Erfindung
durch Linde AG: 10.5.2004.
Sihler, Ch.: Verfahren zur aktiven elektromagnetischen
Dämpfung von Torsionsschwingungen im Wellenstrang von
großen elektrischen Maschinen. PCT-Anmeldung: 7.4.2004.
Antrag auf internationale vorläufige Prüfung: 27.10.2004.
Sihler, Ch.: Vorrichtung und Verfahren zur Anregung einer
Torsionsschwingung in einem rotierenden Antriebsstrang.
Erfindungsmeldung: 22.2.2004. Erfindung wurde unbeschränkt in Anspruch genommen: 16.3.2004. Anmeldung
der Erfindung und Stellung des Prüfantrags: 30.4.2004.
Wittenbecher, K., P. Turba, and K. Klaster: Lichtschranke
mit hoher Störsicherheit. Aufgabe des deutschen Gebrauchsmusters: 7.9.2004.
142
Lectures
Albajar, F., M. Bornatici, G. Cortes, J. Dies, F. Engelmann,
J. Garcia and J. Izquierdo: Importance of Electron
Cyclotron Wave Energy Transport in ITER. (20th IAEA
Fusion Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Bäumel, S., A. Werner, R. Semler, S. Mukherjee, D. S. Darrow,
R. Ellis, F. E. Cecil, V. Kiptily, L. Pedrick, J. Gafert and JETEFDA Contributors: Design of lost alpha particle diagnostics
for JET. (23rd Symposium on Fusion Technology (SOFT),
2004-09-20 till 2004-09-24, Venice).
Alex, J., M. Bader, H. Braune, V. Erckmann, R. Krampitz,
G. Michel, M. Müller, F. Noke, G. Pfeiffer, F. Purps, E. Sachs
and M. Winkler: Design and operation of the Wendelstein
7-X ECRH high voltage power supplies. (23rd Symposium
on Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Balden, M.: Erosion behaviour by hydrogen bombardment
of carbide-doped fine-grain graphites. (Workshop on C &
SiC Composites for Nuclear Applications, 2004-02-17 till
2004-02-18, Petten).
Balden, M.: Materialcharakterisierung. SS 2004. Vorlesung
Werkstofftechnik at Technische Universität München.
Andrew, P., J. P. Coad, Y. Corre, T. Eich, A. Herrmann,
G. F. Matthews, J. I. Paley, L. Pickworth, R. A. Pitts, M. Stamp
and JET EFDA Contributors: Outer divertor target impurity
deposition during reversed magnetic field operation in JET.
(16th International Conference on Plasma Surface Interactions in Controlled Fusion Devices (PSI-16), 2004-05-24
till 2004-05-28, Portland, Maine).
Balden, M.: Mitigation of Chemical Erosion by Doping.
(IPP Workshop on Chemical Sputtering, 2004-02-12,
Garching).
Bécoulet, M., G. Huysmans, P. Thomas, P. Monier-Garbet,
P. Ghendrih, E. Joffrin, F. Rimini, V. Parail, P. Lomas,
G. Matthews, W. Fundamenski, H. Wilson, M. Gryaznevich,
G. Counsell, A. Loarte, G. Saibene, R. Sartori, A. Leonard,
P. Snyder, T. Evans, R. Moyer, P. Gohil, Y. Kamada,
N. Oyama, T. Hatae, A. Degeling, Y. Martin, J. Lister,
J. Rapp, C. Perez, P. Lang, A. Chankin, T. Eich, A. Sips,
L. Horton, A. Herrmann, A. Kallenbach, W. Suttrop,
S. Saarelma, S. Cowley and J. Lonnroth: Edge localized
modes control: experiment and theory. (16th International
Conference on Plasma Surface Interactions in Controlled
Fusion Devices (PSI-16), 2004-05-24 till 2004-05-28,
Portland, Maine).
Angelino, P., A. Bottiono, S. J. Allfrey, R. Hatzky, O. Sauter,
T. M. Tran and L. Villard: Geometric coupling of zonal flows
on electrostatic microinstabilities. (Joint Varenna-Lausanne
International Workshop on Theory of Fusion Plasmas,
2004-08-30 till 2004-09-03, Varenna).
Angelino, P., A. Bottiono, S. J. Allfrey, R. Hatzky, O. Sauter,
T. M. Tran and L. Villard: Zonal flow effects on Tokamak
microinstabilities. (12th International Congress on Plasma
Physics, 2004-10-25 till 2004-10-29, Nice).
Angioni, C.: Particle Transport in Tokamak Plasmas:
Theory, Experiments and Implications for ITER. (IPP
Institutskolloquium, 2004-03-26, Garching).
Behler, K.: Experimentalplanung in europaweiter Zusammenarbeit am Kernfusionsexperiment ASDEX Upgrade.
(Videokonferenztechnologien und ihre Anwendungsszenarien: ”Weit entfernt und doch so nah” (Viktas-Tag 2004),
2004-04-01, Berlin, Dresden, Duisburg, Garching, Jena,
Würzburg).
Angioni, C.: Transition from TEM to ITG and consequences
on transport properties in ASDEX Upgrade plasmas. (10th
EU-US Transport Task Force Workshop, 2004-09-06 till
2004-09-09, Varenna).
Behringer, K.: Aktuelle Fragen der Plasmaphysik. SS 2004,
WS 2004/2005. Seminar at Universität Augsburg.
Asp, E., J. Weiland, X. Garbet, P. Mantica, V. Parail,
W. Suttrop and EFDA-JET Contributors: Te/Ti effects on
JET energy confinement properties. (12th International
Congress on Plasma Physics, 2004-10-25 till 2004-10-29,
Nice).
Behringer, K.: Spektroskopie von Nichtgleichgewichtsplasmen. SS 2004. Vorlesung at Universität Augsburg.
Behringer, K. and U. Fantz: Physikalisches Praktikum für
Fortgeschrittene, Teil B. SS 2004, WS 2004/2005. Vorlesung
at Universität Augsburg.
Bäumel, S., A. Werner, D. S. Darrow and F. E. Cecil: A
Scintillator Probe for Lost Alpha Measurements in JET.
(15th Topical Conference on High Temperature Plasma
Diagnostics (HTPD 2004), 2004-04-19 till 2004-04-25, San
Diego, CA).
Behringer, K., U. Fantz and T. Hamacher: Physikalische
Grundlagen der Energiewandlung und Verteilung. SS 2004,
WS 2004/2005. Seminar at Universität Augsburg.
143
Lectures
Behringer, K., U. Fantz and T. Hamacher: Probleme der
zukünftigen Energieversorgung. SS 2004, WS 2004/2005.
Seminar at Universität Augsburg.
Biedermann, C., R. Radtke, G. Fussmann, J. L. Schwob and
P. Mandelbaum: EUV Spectroscopy of Highly Charged
Xenon Ions. (12th International Conference on the Physics
of Highly Charged Ions (HCI-2004), 2004-09-06 till 200409-10, Vilnius).
Behringer, K., U. Fantz and M. Schreck: Anwendungen und
Diagnostik von Niederdruckplasmen. SS 2004. Seminar at
Universität Augsburg.
Biel, W., J. Baldzuhn, G. Bertschinger, R. Burhenn, M. von
Hellermann, R. König, A. Kreter, P. Mertens, A. Pospieszczyk
and B. Schweer: Development of Spectroscopic Systems for
the Stellarator W7-X. (2nd German-Polish Workshop on
Fusion Diagnostics and Applications (GPPD), 2004-09-08
till 2004-09-10, Krakow).
Behringer, K., M. Stritzker, U. Fantz and H. Schreck:
Diagnostik von Niederdrucktemperaturplasmen als industrielle Schlüsseltechnologie. SS 2004, WS 2004/2005.
Seminar at Universität Augsburg.
Beidler, C. D.: Results from the International Collaboration
in Neoclassical Transport. (IPP-Theory-Week Workshop,
2004-11-08 till 2004-11-12, Schloss Ringberg).
Bilato, R., M. L. Mayoral, F. G. Rimini, M. Brambilla,
D. Hartmann, A. Korotkov, Ph. Lamalle, I. Monakhov,
J.-M. Noterdaeme and R. Sartori: Influence of the plasma
shape on ICRF coupling. (6th TFH Reporting and Planning
Meeting, 2004-04-19 till 2004-04-21, Schloss Ringberg).
Beidler, C. D.: The Shotcomings of the Convertional Rippke
Avarage for Use in Determining Parallel Transport
Coefficients and their Possible Amelioration. (Kinetic
Theory Workshop, 2004-09-13 till 2004-09-15, Graz).
Bizyukov, I., K. Krieger, N. Azarenkov, S. Levchuk and
Ch. Linsmeier: Formation of D inventories and structural
modifications by deuterium bombardment of tungsten thin
films. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Berger, M., U. Fantz and K. Behringer: Diagnostik der
Dichte metastabiler Zustände in Neon- und Argonniederdruckplasmen aus Emissionslinienverhältnissen. (DPGFrühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und Plasmaphysik, 2004-03-08 till
2004-03-11, Kiel).
Bobkov, V., I. Monakhov, T. Blackman, M. Becoulet,
R. Bilato, S. Gerasimov, M.-L. Mayoral, M. Nightingale,
J.-M. Noterdaeme, P. U. Lamalle, G. Saibene, A. Walden and
P. Wouters: ICRF antenna response to ELMs on JET. (6th
TFH Reporting and Planning Meeting, 2004-04-19 till
2004-04-21, Schloss Ringberg).
Berk, H. L., B. N. Breizman, L. Chen, D. E. Eremin, G. Fu,
N. Gorelenkov, M. Gryaznevich, S. Hu, M. S. Pekker,
S. D. Pinches and S. E. Sharapov: Theoretical Studies of
Alfvén Wave-Energetic Particle Interactions. (20th IAEA
Fusion Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Bobkov, V. V., S. S. Alimov, Vl. V. Bobkov, Yu. V. Slyusarenko
and R. I. Starovoitov: Description of evolution of newborn
formations on the cathode of glow or magnetron discharges.
(9th International Conference on Plasma Surface Engineering (PSE 2004), 2004-09-13 till 2004-09-17, GarmischPartenkirchen).
Berk, H. L., S. Sharapov, M. F. Nave, S. D. Pinches and
C. Boswell: Model of n=0 energetic particle induced oscillations in JET. (46th Annual Meeting of the Division of Plasma
Physics, 2004-11-15 till 2004-11-19, Savannah, GA).
Bobkov, Vl. V., F. Braun, D. A. Hartmann, P. Lamalle,
I. Monakhov, J.-M. Noterdaeme, P. Wouters, E. Würsching
and ASDEX Upgrade Team: Influence of ELMs on
Operation of ICRF Antennas in ASDEX Upgrade. (16th
International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI), 2004-05-24 till
2004-05-28, Portland, Maine).
Bessenrodt-Weberpals, M.: Astrophysikalische Plasmen.
SS 2004. Vorlesung at Heinrich-Heine-Universität Düsseldorf.
Bessenrodt-Weberpals, M.: Einführung in die Astrophysik.
SS 2004. Vorlesung at Heinrich-Heine-Universität Düsseldorf.
Bobkov, Vl. V., J.-M. Noterdaeme and R. Wilhelm: Properties
of field emission from high voltage RF antenna. (9th
International Conference on Plasma Surface Engineering
(PSE 2004), 2004-09-13 till 2004-09-17, GarmischPartenkirchen).
Biberacher, M., T. Hamacher, A. M. Bradshaw and
R. P. Shukla: Fusion as a new supply option in long-term
energy studies. (19th World Energy Congress (WEC2004),
2004-09-05 till 2004-09-09, Sydney).
144
Lectures
Bohmeyer, W., D. Naujoks, A. Markin, I. Arkhipov, P. Carl,
B. Koch, D. Schröder and G. Fussmann: Transport and
Deposition of Hydrocarbons in the Plasma Generator PSI-2.
(IPP Workshop on Chemical Sputtering, 2004-02-12,
Garching).
Bosch, H. S.: Magneto-Hydrodynamik. WS 2004/2005. Vorlesung at Humboldt-Universität Berlin.
Bottino, A., P. Angelo, S. J. Allfrey, S. Brunner, R. Hatzky,
Y. Idomura, S. Jolliet, O. Sauter, T. M. Tran and L. Villard:
Recent Advances in Nonlinear Gyrokinetic PIC Simulations
in Tokamak Geometry. (Joint Varenna-Lausanne International Workshop on Theory of Fusion Plasmas,
2004-08-30 till 2004-09-03, Varenna).
Bohmeyer, W., D. Naujoks, A. Markin, I. Arkhipov, B. Koch,
D. Schröder and G. Fussmann: Transport and Deposition of
Injected Hydrocarbons in the Plasma Generator PSI-2. (16th
International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Bradshaw, A. M.: Fusion Research: Bringing the Sun down
to Earth. (Building Excellence: Facing the Needs of FP7,
2004-11-22, Brussels).
Bolt, H., H. Greuner, B. Böswirth, S. Lindig, W. Kühnlein,
T. Huber, K. Sato and S. Suzuki: Vacuum Plasma-Sprayed
Tungsten on EUROFER and 316L - results of characterisation and thermal loading tests. (23rd Symposium on Fusion
Technology (SOFT), 2004-09-20 till 2004-09-24, Venice).
Bradshaw, A. M.: ITER – die Kernfusion auf dem Sprung
nach vorne. (Forum in Berlin, 2004-03-29, Berlin).
Bradshaw, A. M.: ITER – die Kernfusion auf dem Weg nach
vorne. (Kolloquium, 2004-12-13, Technische Universität
München).
Bonnin, X., D. Coster, R. Schneider, D. Reiter, V. Rozhansky
and S. Voskoboynikov: Modelling and consequences of drift
effects in the edge plasma of Alcator C-mod. (16th
International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Bradshaw, A. M.: ITER: Der Weg zur Fusionsenergie. (Jahresversammlung der Deutschen Akademie der Naturforscher
Leopoldina, 2004-02-17, Magnus-Haus, Berlin).
Bradshaw, A. M.: Kernfusion, Möglichkeiten und Chancen
für die Zukunft. (Peutinger-Collegium, 2004-10-27,
München).
Boozer, A. H. and C. Nührenberg: Determination of general
toroidal plasma equilibria by perturbation theory. (46th
Annual Meeting of the Division of Plasma Physics,
2004-11-15 till 2004-11-19, Savannah, GA).
Bradshaw, A. M.: Der Weg zum Fusionskraftwerk. (PTBKolloquium, 2004-10-14, Physikalisch-Technische Bundesanstalt, Braunschweig).
Borba, D., G. D. Conway, S. Günter, G. T. A. Huysmans,
S. Klose, M. Maraschek, A. Mück, I. Nunes, S. D. Pinches,
F. Serra and ASDEX Upgrade Team: Destabilisation of TAE
modes using ICRH in ASDEX Upgrade. (20th IAEA Fusion
Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Brakel, R.: Wendelstein 7-X at the transition from procurement to assembly. (Joint Meeting of the US-Japan Workshop
and Kyoto University 21st COE Symposium on ”New
Approach in Plasma Confinement Experiment in Helical
Systems”, 2004-03-02 till 2004-03-04, Kyoto).
Borchardt, M., H. Leyh, J. Riemann and R. Schneider: Linux
Cluster Computing for Stellarator Studies. (International
Conference on Parallel Computational Fluid Dynamics
(Parallel CFD 2004), 2004-05-24 till 2004-05-27, Las
Palmas).
Brand, P., H. Braune and G. A. Müller: Design and test of a
HV device for protection and power modulation of 140
GHz/1MW CW-gyrotrons used for ECRH on W7-X. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Boscary, J., H. Greuner, K. Scheiber, B. Streibl, B. Schedler,
B. Mendelevitch and J. Schlosser: Applied technologies and
inspections for the W7-X pre-series target elements. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Braune, H., V. Erckmann, J. Hofner, F. Hollmann, L. Jonitz,
H. P. Laqua, G. Michel, F. Noke, F. Purps, T. Schulz,
M. Weissgerber, ECRH Team Stuttgart and ECRH Team
FZK: Commissioning of First Long Pulse Experiments with
the ECRH System for W7-X. (13th Joint Workshop on
Electron Cyclotron Emission and Electron Cyclotron
Resonance Heating (EC-13), 2004-05-17 till 2004-05-20,
Nizhny Novgorod).
Bosch, H. S.: Basic Nuclear Fusion. (IPP Summer
University on Plasma Physics, 2004-09-27 till
2004-10-01, Garching).
145
Lectures
Brendel, A., C. Popescu, H. Schurmann and H. Bolt:
Interface modification of SiC fibre – copper matrix composites by applying a titanium interlayer. (9 th International Conference on Plasma Surface Engineering
(PSE 2004), 2004-09-13 till 2004-09-17, Garmisch-Partenkirchen).
S. Hacquin, N. Hawkes, C. Ingesson, E. Joffrin, V. Kiptily,
M. Mantsinen, M.-L. Mayoral, L. Meneses, F. Meo,
I. Monakhov, A. Murari, J.-M, Noterdaeme, M. Santala,
A. A. Tuccillo, M. Valisa, D. Van Eester, K.-D. Zastrow and
JET EFDA Contributors: New Results on Acceleration of
Deuterons with ICRF Mode Conversion in the JET
Tokamak. (31st EPS on Controlled Fusion and Plasma
Physics, 2004-06-28 till 2004-07-02, London).
Brendel, A., C. Popescu, H. Schurmann and H. Bolt:
Interface properties of SiC fibre reinforced copper matrix
composites. (International Conference ”Advanced Metallic
Materials And Their Joining”, 2004-10-25 till 2004-10-27,
Bratislava).
Cieciwa, B. T., M. Balden, I. Quintana, E. de Juan Pardo,
A. Wiltner, M. Sikora and H. Bolt: Metal-Doped Carbon
Films Obtained by Magnetron Sputtering. (9 th International Conference on Plasma Surface Engineering (PSE
2004), 2004-09-13 till 2004-09-17, GarmischPartenkirchen).
Bunne, S., H. Pfeiffenberger, U. Schwenn and K. Stöckigt:
Programm- und Projektplanung per Videokonferenz in MaxPlanck-Gesellschaft und Helmholtz-Gemeinschaft – eine
Frage der Qualität. (18. DFN-Arbeitstagung über Kommunikationsnetze, 2004-06-01 till 2004-06-04, Düsseldorf).
Cirant, S., F. Gandini, F. Ryter, F. Leuterer, W. Suttrop
and ASDEX Upgrade Team: ∆Te modulation experiments
with ECH on ASDEX Upgrade. (20 th IAEA Fusion
Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Burhenn, R., S. Bäumel and A. Fleischmann: Radiation
Protection at W7-X. (W7-X Progress Report Seminar,
2004-10-26, IPP Greifswald).
Coad, J. P., H.-G. Esser, J. Likonen, M. Mayer, G. Neill,
V. Philipps, M. Rubel, J. Vince and EFDA-JET Contributors:
Diagnostics for studying deposition and erosion processes
in JET. (23rd Symposium on Fusion Technology (SOFT),
2004-09-20 till 2004-09-24, Venice).
Burhenn, R., J. Baldzuhn, R. Brakel, H. Ehmler,
L. Giannone, P. Grigull, J. Knauer, M. Krychowiak,
M. Hirsch, K. Ida, H. Maassberg, K. McCormick, E. Pasch,
H. Thomsen, A. Weller, W7-AS Team, ECRH Group and NI
Group: Impurity confinement studies in the Wendelstein
7-AS stellarator. (Joint Meeting of the US-Japan Workshop
and Kyoto University 21st COE Symposium on ”New
Approach in Plasma Confinement Experiment in Helical
Systems”, 2004-03-02 till 2004-03-04, Kyoto).
Coster, D. P., X. Bonnin, A. Chankin, G. Corrigan, S. K. Erents,
W. Fundamenski, J. Hogan, A. Huber, A. Kallenbach,
G. Kirnev, A. Kirschner, T. Kiviniemi, S. Kuhn, A. Loarte,
J. Lönnroth, G. F. Matthews, R. A. Pitts, S. Sipilä, J. Spence,
J. Strachan, F. Subba, E. Tsitrone, D. Tskhakaya, S. Wiesen,
M. Warrier, M. Wischmeier, R. Zanino and Contributors to the
EFDA-JET Work Programme: Integrated modelling of material migration and target plate power handling at JET. (20th
IAEA Fusion Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Burhenn, R., J. Baldzuhn, R. Brakel, H. Ehmler,
L. Giannone, P. Grigull, J. Knauer, M. Krychowiak,
M. Hirsch, K. Ida, H. Maassberg, K. McCormick, E. Pasch,
H. Thomsen, A. Weller, C. Wendland, W7-AS Team, NBI
Group and ECRH Group: Impurity confinement studies in
the Wendelstein 7-AS stellarator. (LHD Seminar,
2004-03-06, NIFS, Toki).
Coster, D. P., X. Bonnin, G. Corrigan, G. S. Kirnev,
G. Matthews, J. Spence and Contributors to the EFDA-JET
Work Programme: Benchmarking Tokamak edge modelling
codes. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Buttery, R. J., P. Belo, D. P. Brennan, S. Coda,
L.-G. Eriksson, B. Goncalves, J. P. Graves, S. Günter,
C. Hegna, T. C. Hender, D. F. Howell, H. R. Koslowski,
R. J. La Haye, M. Maraschek, M. L. Mayoral, A. Mück,
M. F. F. Nave, O. Sauter, E. Westerhof, C. G. Windsor,
ASDEX Upgrade Team, DIII-D Team and JET-EFDA
Contributors: Cross-machine NTM physics studies and
implications for ITER. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Dammertz, G., D. Bariou, P. Brand, H. Braune, V. Erckmann,
G. Gantenbein, E. Giguet, W. Kasparek, H. P. Laqua, C. Lievin,
W. Leonhardt, G. Michel, G. Müller, G. Neffe, B. Piosczyk,
M. Schmid and M. Thumm: 140-GHz high-power gyrotron
development for the stellarator W7-X. (23rd Symposium on
Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Castaldo, C., R. Cesario, A. Cardinali, Y. Andrew,
P. Beaumont, L. Bertalot, D. Bettella, R. Felton, C. Giroud,
146
Lectures
DeBoo, J. C., S. Cirant, T. C. Luce, A. Manini, C. C. Petty,
F. Ryter, M. E. Austin, D. R. Baker, K. Gentle,
C. M. Greenfield, J. E. Kinsey, G. M. Staebler and ASDEX
Upgrade Team: Search for a critical electron temperature
gradient in DIII D L-mode discharges. (20th IAEA Fusion
Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Dux, R., R. Neu, A. Herrmann, V. Hynönen, A. Kallenbach,
B. Kurzan, T. Kurki-Suonio, J. Neuhauser, C. Maggi,
H. Maier, R. Pugno, T. Pütterich, V. Rohde, A. Stäbler and
ASDEX Upgrade Team: Plasma Surface Interaction with
Tungsten in ASDEX Upgrade. (16th International Conference on Plasma Surface Interactions in Controlled Fusion
Devices (PSI-16), 2004-05-24 till 2004-05-28, Portland,
Maine).
Dinklage, A.: Data Analysis with Matlab. SS 2004.
Vorlesung at Universität Greifswald.
Dux, R., R. Neu, C. F. Maggi, A. G. Peeters, G. Pereverzev,
A. Mück, F. Ryter, J. Stober, B. Zaniol and ASDEX Upgrade
Team: Impurity Transport and Control in ASDEX Upgrade.
(20th IAEA Fusion Energy Conference, 2004-11-01 till
2004-11-06, Vilamoura).
Dinklage, A.: Integrated Data Analysis. (3rd Workshop on
Fusion Data Processing, Validation and Analysis,
2004-09-15 till 2004-09-17, Cadarache).
Dinklage, A., R. Fischer, J. Svensson and Y. Turkin: Integrated Data Analysis and interpretative Modelling. (24th
International Workshop on Bayesian Inference and
Maximum Entropy Methods in Science and Engineering
(MaxEnt ‘04), 2004-07-25 till 2004-07-30, Garching).
Dyckhoff, W.: Als Physiker/in in der Max-Planck-Gesellschaft/Großforschung. (Arbeitsamt, 2004-03-11, München).
Eich, T.: Power deposition onto PFC in poloidal divertor
tokamaks during ELMs and disruptions. (16th International
Conference on Plasma Surface Interactions in Controlled
Fusion Devices (PSI-16), 2004-05-24 till 2004-05-28,
Portland, Maine).
Doerner, R. P., M. J. Baldwin, S. I. Krasheninnikov and
K. Schmid: High temperature erosion of Beryllium. (16th
International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Endler, M., I. Garcia-Cortés, C. Hidalgo, G. F. Matthews,
ASDEX Upgrade Team and JET Team: The fine structure of
ELMs. (31st EPS Conference on Plasma Physics, 2004-0628 till 2004-07-02, London).
Dose, V.: A decade of Bayesian analysis at IPP - A historical
review. (24th International Workshop on Bayesian Inference
and Maximum Entropy Methods in Science and Engineering
(MaxEnt ‘04), 2004-07-25 till 2004-07-30, Garching).
Ezumi, N., Z. Kiss’ovski, W. Bohmeyer and G. Fussmann:
Ion sensitive probe measurement in the linear plasma device
PSI-2. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-04-28, Portland, Maine).
Dreier, H., A. Dinklage, R. Fischer, M. Hirsch and
J. Svensson: Concepts for Diagnostics Performance
Optimization. (24th International Workshop on Bayesian
Inference and Maximum Entropy Methods in Science and
Engineering (MaxEnt ‘04), 2004-07-25 till 2004-07-30,
Garching).
Falter, H. D., M. Bandyopadhyay, U. Fantz, P. Franzen,
B. Heinemann, W. Kraus, P. McNeely, R. Riedl, E. Speth,
A. Tanga and R. Wilhelm: Status and Plans for the Development of an RF Negative Ion Source for ITER NBI.
(20th IAEA Fusion Energy Conference, 2004-11-01 till
2004-11-06, Vilamoura).
Dremel, M., A. Mack, C. Day, H. Jensen, E. Speth,
H. D. Falter, R. Riedl, J. J. Cordier and B. Gravil: Design of
cryosorption pumps for testbeds of ITER relevant neutral
beam injectors. (23rd Symposium on Fusion Technology
(SOFT), 2004-09-20 till 2004-09-24, Venice).
Falter, H. D. and NBI Group: Achievements and prospects
of the RF source development. (CCNB Meeting,
2004-11-30 till 2004-12-02, Madrid).
Düchs, D.: Plasma, ein komplexes und nichtlineares
System; Methoden zur theoretischen Beschreibung. SS
2004. Vorlesung at Ruhr-Universität Bochum.
Falter, H. D. and NBI Group: Status of the preparations for
long pulse operation & ITER half size source. (CCNB
Meeting, 2004-06-08 till 2004-06-09, Dublin).
Düweke, J., T. Hamacher, M. Biberacher and R. P. Shukla:
The role of fusion in the energy economy of the 21st century.
(Jahrestagung Kerntechnik, 2004-05-25 till 2004-05-27,
Düsseldorf).
Fantz, U.: Basics of plasma spectroscopy. (European Marie
Curie Training Course on “Low Temperature Plasma
147
Lectures
Physics: Basics and Applications”, 2004-09-26 till
2004-10-05, Bad Honnef).
Devices (PSI-16), 2004-05-24 till 2004-05-28, Portland,
Maine).
Fantz, U.: Comparison of plasma parameters between RF
and arc sources. (CCNB Meeting, 2004-11-30 till
2004-12-02, Madrid).
Faugel, H., P. Angene, W. Becker, V. Bobkov, F. Braun,
B. Eckert, F. Fischer, G. Heilmaier, J. Kneidl,
J.-M. Noterdaeme, G. Siegl and E. Würsching: The ASDEX
Upgrade ICRF System: Operational Experience and
Developments. (23rd Symposium on Fusion Technology
(SOFT), 2004-09-20 till 2004-09-24, Venice).
Fantz, U.: Diagnostics of molecules in technology and
fusion plasmas. (Kolloquium, 2004-05-27, Stockholm).
Fantz, U.: Diagnostics of reactive plasmas. (Physikalisches
Kolloquium,
2004-01-21, Technische
Universität
Chemnitz).
Fischer, R.: Diagnostic Design with Bayesian Probability
Theory. (3rd Workshop on Fusion Data Processing,
Validation and Analysis, 2004-09-15 till 2004-09-17,
Cadarache).
Fantz, U.: Effective rate coefficients for molecular processes
of hydrogen and hydrocarbons in edge plasmas. (CRP (Coordinated Research Project) on ”Data for Molecular
Processes in Edge Plasmas”, 2004-11-01 till 2004-11-02,
Vienna).
Fischer, R., A. Dinklage, H.-J. Hartfuss and J. Svensson:
Integrated Data Analysis of BPX Diagnostics. (6th ITPA
Topical Group Meeting on Diagnostics, 2004-04-23 till
2004-04-24, San Diego, CA).
Fantz, U.: Emissionsspektroskopie an molekularen
Niederdruckplasmen. (DPG-Frühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und
Plasmaphysik, 2004-03-08 till 2004-03-11, Kiel).
Franzen, P.: Development of an RF source for ITER NBI:
Recent progress and perspectives. (IPP Institutskolloquium,
2004-09-17, Garching).
Franzen, P., H.-D. Falter, M. Bandyopadhyay, U. Fantz,
B. Heinemann, W. Kraus, P. McNeely, R. Riedl, E. Speth,
A. Tanga and R. Wilhelm: Status and Plans for the
Development of an RF Negative Ion Source for ITER NBI.
(23rd Symposium on Fusion Technology (SOFT),
2004-09-20 till 2004-09-24, Venice).
Fantz, U.: Molecular diagnostics of fusion and laboratory
plasmas. (146th International Toki Conference on Plasma
Physics and Controlled Nuclear Fusion and 4th International
Conference on Atomic and Molecular Data and Their
Applications (Joint ITC14 and ICAMDATA2004),
2004-10-05 till 2004-10-08, Gifu).
Franzen, P., J. Sielanko, H. P. L. de Esch, B. Heinemann,
R. Riedl and E. Speth: Progress on the MIRS concept.
(CCNB Meeting, 2004-11-30 till 2004-12-02, Madrid).
Fantz, U.: Die physikalische Natur von Regenbogen, Blitzen
und Polarlichtern. (Naturwissenschaftliche Projektwoche,
2004-04-19, Gymnasium Bad Aibling).
Franzen, P., J. Sielanko, B. Heinemann, R. Riedl and
E. Speth: Possible future work on the magnetic residual ion
dump. (CCNB Meeting, 2004-11-30 till 2004-12-02,
Madrid).
Fantz, U.: Plasmaphysik und Fusionsforschung I.
WS 2004/2005. Vorlesung at Universität Augsburg.
Fantz, U.: Plasmaphysik und Fusionsforschung II.
SS 2004. Vorlesung at Universität Augsburg.
Fuchs, J. C., T. Eich, A. Herrmann, K. F. Mast and ASDEX
Upgrade Team: Radiation distribution and energy balance
during type-I ELMs in ASDEX Upgrade. (16th International
Conference on Plasma Surface Interactions in Controlled
Fusion Devices (PSI-16), 2004-05-24 till 2004-05-28,
Portland, Maine).
Fantz, U., M. Bandyopadhyay, H. D. Falter, P. Franzen,
B. Heinemann, W. Kraus, P. McNeely, R. Riedl, E. Speth,
A. Tanga and R. Wilhelm: Diagnostics of the Cesium amount
in a RF negative ion source and the correlation with the
extracted current density. (23rd Symposium on Fusion
Technology (SOFT), 2004-09-20 till 2004-09-24, Venice).
Fussmann, G.: Einführung in die Plasmaphysik. SS 2004,
WS 2004/2005. Vorlesung at Humboldt-Universität Berlin.
Fantz, U., S. Meir and ASDEX Upgrade Team: Correlation
of the intensity ratio of C2/CH molecular bands with the flux
ratio of C2Hy/CH4 particles. (16th International Conference
on Plasma Surface Interactions in Controlled Fusion
Fussmann, G., N. Ezumi, T. Lunt and W. Bohmeyer:
Experimental Investigations with Respect to the Applicability of the Bohm Criterion. (16th International Con148
Lectures
ference on Plasma Surface Interactions in Controlled Fusion
Devices (PSI-16), 2004-05-24 till 2004-05-28, Portland,
Maine).
des W7-X. (IPP Institutskolloquium, 2004-10-08, Garching).
Greuner, H., B. Böswirth, T. Franke, P. McNeely and N. Rust:
Design, Performance and Construction of a 2 MW Ion
Beam Test Facility for Plasma Facing Components. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Gál, K., S. Kálvin, G. Kocsis, P. T. Lang, R. Schneider,
G. Veres and ASDEX Upgrade Team: Modeling the ablation
of cryogenic deuterium pellets induced by hot plasmas. (2nd
Hungarian Plasma Physics Workshop, 2004-04-22 till
2004-04-24, Budapest).
Grieger, G.: Hermann Renner und die WendelsteinStellaratoren. Sonderkolloquium anlässlich des Ausscheidens von Dr. Hermann Renner. (IPP Institutskolloquium,
2004-07-30, Garching).
Gao, L., J. Gstöttner, R. Emling, M. Balden, C. Linsmeier,
A. Wiltner, W. Hansch and D. Schmitt-Landsiedel: Thermal stability of titanium nitride diffusion barrier films for advanced
silver interconnects. (Materials for Advanced Metallization
(MAM 2004), 2004-03-07 till 2004-03-10, Brussels).
Gruber, O.: Development of an ITER relevant advanced scenario at ASDEX Upgrade. (46th Annual Meeting of the
Division of Plasma Physics, 2004-11-15 till 2004-11-19,
Savannah, GA).
Gao, L., J. Gstöttner, R. Emling, Ch. Linsmeier, M. Balden,
A. Wiltner, W. Hansch and D. Schmitt-Landsiedel: Silver
Metallization with Reactively Sputtered TiN Diffusion
Barrier Films. (2004 MRS Spring Meeting, 2004-04-12 till
2004-04-16, San Francisco, CA).
Gruber, O.: Device schedules and programme elements in
2005. (3rd Joint Workshop of IEA Implementing Agreements
on ”Implementation of the ITPA Coordinated Research
Recommendations”, 2004-12-08 till 2004-12-10, Near
Oxford).
Gao, L., P. Härter, Ch. Linsmeier, J. Gstöttner, R. Emling
and D. Schmitt-Landsiedel: Metalorganic chemical vapor
deposition of silver thin films by direct liquid injection system for future interconnects. (E-MRS Spring Meeting 2004,
2004-05-24 till 2004-05-28, Strasbourg).
Gruber, O.: Report of ITPA TG on MHD, disruption and
control. (5th Meeting of the ITPA Coordinating Committee,
2004-06-10 till 2004-06-11, Shanghai).
García Muñoz, M., A. Bergmann, J. Kisslinger,
H.-U. Fahrbach, J. Neuhauser, S. Pinches, A. Stäbler and
H. Zohm: Fast Ion Losses in ASDEX Upgrade. (DPGFrühjahrstagung der Fachverbände Extraterrestrische
Physik, Kurzzeitphysik und Plasmaphysik, 2004-03-08 till
2004-03-11, Kiel).
Gruber, O.: Report on tokamak physics basis chapters 3 and
8. (5th Meeting of the ITPA Coordinating Committee,
2004-06-10 till 2004-06-11, Shanghai).
Gruber, O. and ASDEX Upgrade Team: ASDEX Upgrade –
status and plans. (18th Executive Committee Meeting on
IEA Cooperation among Large Tokamak Facilities,
2004-06-14 till 2004-06-15, Naka).
Gasparotto, M., V. Erckmann, W. Gardebrecht, T. Rummel,
T. Schauer, M. Wanner, L. Wegener and W7-X Team: W7-X
Progress. (16th ANS Topical Meeting on the Technology of
Fusion Energy (16th TOFE), 2004-09-14 till 2004-09-16,
Madison, WI).
Gruber, O., D. Merkl, J. Hobirk, P. J. McCarthy,
E. Strumberger and ASDEX Upgrade Team: Current holes at
ASDEX Upgrade. (Large Tokamak Workshop W56 on
”Physics of Current Holes”, 2004-02-03 till 2004-02-04,
Mito).
Gasparotto, M., J. Simon-Weidner, F. Elio, B. Heinemann,
N. Jaksic, B. Mendelevitch and B. Streibl: The Wendelstein
7-X Mechanical Structure Support Elements: Design and
Tests. (23rd Symposium on Fusion Technology (SOFT),
2004-09-20 till 2004-09-24, Venice).
Gruber, O. and H. Zohm: Power requirements for NTM stabilization by ECRF on ITER. (5th Meeting of the ITPA TG
on MHD, Disruption and Control, 2004-11-08 till
2004-11-10, Lisbon).
Geiger, J.: Analysis of diamagnetic measurements on
W7-AS. (3rd Workshop on Fusion Data Processing, Validation
and Analysis, 2004-09-15 till 2004-09-17, Cadarache).
Grulke, O., J. L. Terry, B. LaBombard and S. J. Zweben:
Characterization of turbulent SOL fluctuation structures in
the ALCATOR C-Mod tokamak. (16th International
Conference on Plasma Surface Interactions in Controlled
Greuner, H.: Konzeptentwicklung, Design und Erprobung
der Plasma belasteten Komponenten für den Langpulsbetrieb
149
Lectures
Fusion Devices (PSI-16), 2004-05-24 till 2004-05-28,
Portland, Maine).
D. Zasche, T. Zehetbauer, H.-P. Zehrfeld, M. Zilker and
H. Zohm: Overview of ASDEX Upgrade Results. (20th IAEA
Fusion Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Grulke, O., J. L. Terry, B. LaBombard and S. J. Zweben:
Propagation of turbulent structures in the SOL of ALCATOR
C-Mod: Comparison between Ohmic and EDA discharges.
(31st EPS Conference on Plasma Physics, 2004-06-28 till
2004-07-02, London).
Guglielmetti, F., R. Fischer, W. Voges, G. Boese and V. Dose:
Source Detection and Background Estimation with Bayesian
Inference. (Integral Workshop, 2004-02-16 till 2004-02-20,
München).
Günter, S.: Experimentelle Plasmaphysik I. WS 2004.
Vorlesung at Technische Universität München.
Hallatschek, K. and K. Itoh: Forces on Zonal Flows in
Stationary Tokamak Core Turbulence. (20 th IAEA Fusion
Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Günter, S.: Instabilities and wave-particle interaction in
magnetically confined plasmas. (SFB 591 Kolloquium,
2004-05-11, Ruhr-Universität Bochum).
Hamacher, T., B. Chateau, M. Biberacher and VLEEM
Consortium: The Very Long Energy and Enviromental
Model (VLEEM): Outline of the Methodology. (Annual
Meeting of the International Energy Workshop (IEW),
2004-06-22 till 2004-06-24, Paris).
Günter, S., C. Angioni, M. Apostoliceanu, C. Atanasiu,
M. Balden, G. Becker, W. Becker, K. Behler, K. Behringer,
A. Bergmann, R. Bilato, I. Bizyukov, V. Bobkov, T. Bolzonella,
D. Borba, K. Borrass, M. Brambilla, F. Braun, A. Buhler,
A. Carlson, A. Chankin, J. Chen, S. Cirant, G. Conway,
D. Coster, T. Dannert, K. Dimova, R. Drube, R. Dux, T. Eich,
K. Engelhardt, H.-U. Fahrbach, U. Fantz, L. Fattorini,
M. Foley, P. Franzen, J. C. Fuchs, J. Gafert, K. Gal,
G. Gantenbein, M. Garcia Munoz, O. Gehre, A. Geier,
L. Giannone, O. Gruber, G. Haas, D. Hartmann, B. Heger,
B. Heinemann, A. Herrmann, J. Hobirk, H. Hohenöcker,
L. Horton, M. Huart, V. Igochine, A. Jacchia, M. Jakobi,
F. Jenko, A. Kallenbach, S. Kalvin, O. Kardaun,
M. Kaufmann, A. Keller, A. Kendl, M. Kick, J.-W. Kim,
K. Kirov, S. Klose, R. Kochergov, G. Kocsis, H. Kollotzek,
C. Konz, W. Kraus, K. Krieger, T. Kurki-Suonio, B. Kurzan,
K. Lackner, P. T. Lang, P. Lauber, M. Laux, F. Leuterer,
J. Likonen, A. Lohs, A. Lorenz, R. Lorenzini, A. Lyssoivan,
C. Maggi, H. Maier, K. Mank, A. Manini, M.-E. Manso,
P. Mantica, M. Maraschek, P. Martin, K. F. Mast, H. Mayer,
M. Mayer, P. McCarthy, D. Meisel, H. Meister, S. Menmuir,
F. Meo, P. Merkel, R. Merkel, D. Merkl, V. Mertens,
F. Monaco, A. Mück, H. W. Müller, M. Münich, H. Murmann,
Y.-S. Na, R. Narayanan, G. Neu, R. Neu, J. Neuhauser,
D. Nishijima, Y. Nishimura, J.-M. Noterdaeme, I. Nunes,
M. Pacco-Düchs, G. Pautasso, A. G. Peeters, G. Pereverzev,
S. Pinches, E. Poli, T. Pütterich, R. Pugno, E. Quigley,
I. Radivojevic, G. Raupp, M. Reich, R. Riedl, T. Ribeiro,
V. Rohde, J. Roth, F. Ryter, S. Saarelma, W. Sandmann,
J. Santos, G. Schall, H.-B. Schilling, J. Schirmer,
W. Schneider, G. Schramm, J. Schweinzer, S. Schweizer,
B. Scott, U. Seidel, F. Serra, C. Sihler, A. Silva, A. Sips,
E. Speth, A. Stäbler, K.-H. Steuer, J. Stober, B. Streibl,
D. Strintzi, E. Strumberger, W. Suttrop, G. Tardini,
C. Tichmann, W. Treutterer, M. Troppmann, M. Tsalas,
H. Urano, P. Varela, D. Wagner, F. Wesner, E. PosthumusWolfrum, E. Würsching, M. Y. Ye, S.-W. Yoon, Q. Yu, B. Zaniol,
Hamacher, T., J. Düweke, T. Haase and H. Weber:
Integration of Large Scale Wind Power into the Electricity
Grid. (Power-Gen Europe, 2004-05-25 till 2004-05-27,
Barcelona).
Hamacher, T., T. Haase and H. Weber: Einfluss der Einspeisung von Windenergie auf die Struktur des Kraftwerkparks und des Übertragungsnetzes. (VDE-Kongress,
2004-10-18 till 2004-10-20, Berlin).
Harmeyer, E., A. Wieczorek and H. Wobig: Optimization of
the Power Supply for a Helias Reactor Superconducting Coil
System. (23rd Symposium on Fusion Technology (SOFT),
2004-09-20 till 2004-09-24, Venice).
Hartfuss, H.-J.: Diagnostic Opportunities of W7-X. (2nd
German-Polish Conference on Plasma Diagnostics for
Fusion and Applications (GPPD-2004), 2004-09-08 till
2004-09-10, Cracow).
Hartfuss, H.-J.: Diagnostics in a harsh environment. (12th
European Fusion Physics Workshop, 2004-12-06 till
2004-12-08, Witney).
Hartfuss, H.-J.: Diagnostik von Hochtemperaturplasmen. Physikalisches Praktikum für Fortgeschrittene I.
WS 2003/2004. Vorlesung at Universität Greifswald.
Hartfuss, H.-J.: Diagnostik von Hochtemperaturplasmen. Physikalisches Praktikum für Fortgeschrittene II.
SS 2004. Vorlesung at Universität Greifswald.
150
Lectures
Hartfuss, H.-J.: Diagnostik von Hochtemperaturplasmen.
Physikalisches Praktikum für Fortgeschrittene I.
WS 2004/2005. Vorlesung at Universität Greifswald.
scale. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Hartfuss, H.-J.: Kosmische Radiostrahlung. (Lange Nacht
der Sterne, 2004-09-18, Universität Greifswald).
Herrmann, A., J. Neuhauser, G. Pautasso, V. Bobkov, R. Dux,
T. Eich, C. J. Fuchs, O. Gruber, C. Maggi, H. W. Müller,
V. Rohde, M. Y. Ye and ASDEX Upgrade Team: Wall and
Divertor Load during ELMy H-mode and Disruptions in
ASDEX Upgrade. (20th IAEA Fusion Energy Conference,
2004-11-01 till 2004-11-06, Vilamoura).
Hartfuss, H.-J.: W7-X project and diagnostic opportunities.
(15th Topical Conference on High Temperature Plasma
Diagnostics, 2004-04-19 till 2004-04-22, San Diego, CA).
Hartfuss, H.-J., V. Erckmann, M. Hirsch, H. Laqua,
S. Ullrich, F. Gandini and S. Cirant: ECRH Stray Radiation
Material Test Chamber. (15th Topical Conference on High
Temperature Plasma Diagnostics, 2004-04-19 till 2004-04-22,
San Diego, CA).
Herrmann, A., J. Neuhauser, V. Rohde, R. Dux, T. Eich,
C. J. Fuchs, M. Ye and ASDEX Upgrade Team: Interaction of
ELMs and fast particles with in vessel components in
ASDEX Upgrade. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Hartmann, D., A. Lyssoivan, J.-M. Noterdaeme, V. Bobkov,
T. Blackman, M. Cox, P. de Vries, E. Gauthier, M. Graham,
A. Huber, A. Kaye, R. Koch, K. Lawson, P. J. Lomas,
M. Mantsinen, G. Matthews, M.-L. Mayoral, A. Meigs,
Ph. Mertens, I. Monakhov, M. Nightingale, R. Pearce,
V. Philipps, M. Santala, M. Stamp, D, Stork, A. Walden and
D. Van Eester: ICRF Plasma Production for Wall
Conditioning on JET. (6th TFH Reporting and Planning
Meeting, 2004-04-19 till 2004-04-21, Schloss Ringberg).
Hildebrandt, D., D. Naujoks and D. Sünder: Surface
Temperature Measurements of Carbon Materials in Fusion
Devices. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Hirsch, M.: Energieerzeugung durch Kernfusion - Wie in
der Sonne so im Reaktor? (Vortragsreihe der OlbersGesellschaft e.V., 2004-11-16, Bremen).
Hatzky, R., A. Könies and A. Mishchenko: Electromagnetic
PIC simulations with a δf method constructing the adiabatic
current. (Joint Varenna-Lausanne International Workshop on
Theory of Fusion Plasmas, 2004-08-30 till 2004-09-03,
Varenna).
Hirsch, M.: Interferometrie zur Messung der Elektronendichte in Fusions- und Laborplasmen. (Seminar, 2004-11-30,
Universität Greifswald).
Hirsch, M.: Microwave Diagnostics for Fusion Plasmas. (2nd
German-Polish Conference on Plasma Diagnostics for
Fusion and Applications (GPPD-2004), 2004-09-09 till
2004-09-10, Crakow).
Heikkinen, J. A., A. Salmi, Vl. V. Bobkov, T. Hellsten,
P. U. Lamalle, M. Mantsinen and J.-M. Noterdaeme: Parasitic
absorption, dependence on spectrum, consequences for the
JET-EP design. (6th TFH Reporting and Planning Meeting,
2004-04-19 till 2004-04-21, Schloss Ringberg).
Hobirk, J. and C. D. Challis: Neutral beam current drive
experiments in JET. (6th TFH Reporting and Planning
Meeting, 2004-04-19 till 2004-04-21, Schloss Ringberg).
Hennig, C.: Datenerfassung an einem physikalischen
Großexperiment. (Informatica Feminale, Sommeruniversität
für Frauen in der Informatik, 2004-09-06 till 2004-09-17,
Universität Bremen).
Höllt, L., W. Suttrop, L. Giannone, C. Sihler, A. C. C. Sips,
D. Zasche and ASDEX Upgrade Team: ”Flight Simulator”
for ASDEX Upgrade Plasmas. (DPG-Frühjahrstagung der
Fachverbände Extraterrestrische Physik, Kurzzeitphysik und
Plasmaphysik, 2004-03-08 till 2004-03-11, Kiel).
Hentges, R., O. Kugeler, D. Rolles, G. Prümper, M. Braune,
T. Lischke, S. Marburger, J. Viefhaus, U. Hergenhahn and
U. Becker: Intramolekulare Streuung von Auger-Elektronen
in dissoziierenden Molekülen hoher Symmetrie. (DPG – 68.
Physikertagung und AMOP-Frühjahrstagung, 2004-03-22
till 2004-03-26, München).
Horton, L.: H-mode physics at ASDEX Upgrade. (IPP
Institutskolloquium, 2004-04-30, Garching).
Horton, L. D., A. V. Chankin, Y. P. Chen, G. D. Conway,
D. P. Coster, T. Eich, B. Kurzan, J. Neuhauser, I. Nunes,
M. Reich, S. Saarelma, J. Schirmer, J. Schweinzer,
Herrmann, A.: Thermal properties of plasma exposed carbon and heat flux calculation on a few micrometer spatial
151
Lectures
E. Wolfrum and ASDEX Upgrade Team: Characterisation of
the H-mode Edge Barrier at ASDEX Upgrade. (20th IAEA
Fusion Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Jacob, W.: Redeposition of Hydrocarbon Layers in Fusion
Devices. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
ITPA H-Mode Database Working Group and J. G. Cordey:
The scaling of confinement in ITER with‚ and collisionality.
(20th IAEA Fusion Energy Conference, 2004-11-01 till
2004-11-06, Vilamoura).
Jacob, W.: Tutorial: Chemical Sputtering of Carbon: Review
of Literature Data and Actual Results. (IPP Workshop on
Chemical Sputtering, 2004-02-12, Garching).
Jacob, W., C. Hopf, M. Schlüter and T. Schwarz-Selinger: A
Microscopic Model for Chemical Sputtering of Carbon.
(16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Igitkhanov, Yu., E. Polunovsky, C. D. Beidler and
K. Yamazaki: Impurity Dynamics in Stellarator Plasmas.
(14th International Toki Conference on Plasma Physics and
Controlled Nuclear Fusion and 4th International Conference
on Atomic and Molecular Data and Their Applications,
2004-10-05 till 2004-10-08, Gifu).
Jauregi, E., D. Ganuza, F. García, J. M. Del Río, J. Lucas,
T. Rummel and F. Füllenbach: Commissioning of the 10
power supplies of the control coils of Wendelstein 7-X
experiment. (23rd Symposium on Fusion Technology
(SOFT), 2004-09-20 till 2004-09-24, Venice).
Jacchia, A., C. Angioni, S. Cirant, F. De Luca, A. Manini,
P. Mantica, F. Ryter, M. Apostoliceanu, G. Conway,
H.-U. Fahrbach, K. K. Kirov, F. Leuterer, M. Reich,
W. Suttrop, J. Weiland and ASDEX Upgrade Team: Electron
Heat Transport Studies Using Transient Phenomena in
ASDEX Upgrade. (20th IAEA Fusion Energy Conference,
2004-11-01 till 2004-11-06, Vilamoura).
Jenko, F.: Electromagnetic effects on plasma turbulence and
transport. (10th EU-US Transport Task Force Workshop,
2004-09-06 till 2004-09-09, Varenna).
Jacchia, A., F. De Luca, F. Ryter, A. Bruschi, F. Leuterer,
R. Neu, G. Pereverzev, W. Suttrop, D. Wagner and ASDEX
Upgrade Team: Non-linear pertubative electron heat transport
study in ASDEX Upgrade tokamak. (10th EU-US Transport
Task Force Workshop, 2004-09-06 till 2004-09-09, Varenna).
Jenko, F.: Non-linear gyrokinetic description of burning
plasmas. (12th European Fusion Physics Workshop,
2004-12-06 till 2004-12-08, Witney).
Jenko, F.: Turbulenz in magnetisierten Hochtemperaturplasmen. (DPG-Frühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und Plasmaphysik,
2004-03-08 till 2004-03-11, Kiel).
Jacchia, A., F. De Luca, F. Ryter, A. Bruschi, F. Leuterer,
R. Neu, G. Pereverzev, W. Suttrop, D. Wagner and ASDEX
Upgrade Team: Non-linear pertubative electron heat transport study in ASDEX Upgrade tokamak. (Transport Task
Force Workshop on Electron Transport, 2004-02-19 till
2004-02-20, Milano).
Jenko, F., T. Dannert and C. Angioni: Heat and particle
transport: nonlinear gyrkokinetic simulations. (10th EU-US
Transport Task Force Workshop, 2004-09-06 till
2004-09-09, Varenna).
Jacob, C.: Optimierung der Spannungsreglung einer
schleifringlosen Synchronmaschine. (11. Symposium
”Maritime Elektrotechnik, Elektronik und Informationstechnik”, 2004-06-03 till 2004-06-04, Rostock).
Joffrin, E., A. C. C. Sips, A. Becoulet, R. Budny, P. Buratti, P. da
Silva Aresta Belo, C. D. Challis, F. Crisanti, M. de Baar,
P. de Vries, C. Gormezano, C. Giroud, O. Gruber,
G. T. A. Huysmans, F. Imbeaux, A. Isayama, X. Litaudon,
P. J. Lomas, D. C. McDonald, Y. S. Na, S. D. Pinches,
A. Staebler, T. Tala, A. Tuccillo, K.-D. Zastrow and JET-EFDA
Contributors to the Work Programme: The ”hybrid” scenario
in JET: towards its validation for ITER. (20th IAEA Fusion
Energy Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Jacob, W.: Chemische Zerstäubung von Kohlenstoff durch
Wasserstoff. (11. Erfahrungsaustausch Oberflächentechnologie mit Plasmaprozessen, 2004-03-02 till 2004-03-04,
Mühlleithen).
Jacob, W.: A Quantitative Model for Chemical Sputtering of
Carbon Materials in Thermonuclear Fusion Devices. (7th
International Workshop on Hydrogen Isotopes in Fusion
Reactor Materials, 2004-05-20 till 2004-05-21, Portland,
Maine).
Käsemann, C.-P., L. Van Lieshout, M. Huart and C. Sihler:
Thyristor crowbar system for the high current power supplies of ASDEX Upgrade. (23rd Symposium on Fusion
Technology (SOFT), 2004-09-20 till 2004-09-24, Venice).
152
Lectures
Kallenbach, A.: Energy and particle exhaust control in a
burning plasma. (12th European Fusion Physics Workshop,
2004-12-06 till 2004-12-08, Witney).
Kaufmann, M.: Zwischenbericht eines Forscherlebens. Sonderkolloquium anläßlich des Ausscheidens von Prof. Dr. Rolf
Wilhelm. (IPP Institutskolloquium, 2004-02-20, Garching).
Kallenbach, A.: Energieszenarien für das 21. Jahrhundert.
SS 2004, WS 2004/2005. Vorlesung at Universität
Hannover.
Kendl, A. and B. Scott: Flux surface shaping effects on tokamak edge turbulence and flows. (12th International Congress
on Plasma Physics, 2004-10-25 till 2004-10-29, Nice).
Kallenbach, A.: Stand und Perspektiven der Kernfusion mit
magnetischem Einschluss. (Kolloquium, 2004-12-14,
Universität Hannover).
Kim, B. Y. and J. H. You: FEM-based shakedown analysis of
fiber-reinforced composites for variable thermomechanical
loading. (22. CAD-FEM Users’ Meeting 2004 –
Internationale FEM-Technologietage & ANSYS CFX &
ICEM CFD Conference, 2004-11-10 till 2004-11-12,
Dresden).
Kallenbach, A.: Stand und Perspektiven der Kernfusion mit
magnetischem Einschluss. SS 2004. Vorlesung at
Universität Hannover.
Kirnev, G. S., G. Corrigan, D. Coster, S. K. Erents and
G. F. Matthews: Edge code simulations of SOL flows
in JET. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Kallenbach, A., N. Asakura, A. Korotkov, D. Mossessian and
G. D. Porter: Multi-machine comparisons of H-Mode separatrix densities and edge behaviour in the ITPA SOL and
divertor physics topical group. (16th International Conference on Plasma Surface Interactions in Controlled Fusion
Devices (PSI-16), 2004-05-24 till 2004-05-28, Portland,
Maine).
Kirschner, A., V. Phillips, D. P. Coster, S. K. Erents,
H. G. Esser, G. Federici, A. S. Kukushkin, A. Loarte,
G. F. Matthews, J. Roth, U. Samm and JET EFDA
Contributors: Experimental observations and modelling of
carbon transport in the inner divertor of JET and extrapolations to ITER. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Kallenbach, A., P. T. Lang, R. Dux, C. Fuchs, A. Herrmann,
H. Meister, V. Mertens, R. Neu, T. Pütterich, T. Zehetbauer
and ASDEX Upgrade Team: Integrated exhaust control with
divertor parameter feedback and pellet ELM pacemaking in
ASDEX Upgrade. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Kisslinger, J. and T. Andreeva: Correction Possibilities of
Magnetic Field Errors in Wendelstein 7-X. (23rd Symposium
on Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Kasparek, W., H. Braune, G. Dammertz, V. Erckmann,
G. Gantenbein, F. Hollmann, M. Grünert, H. Kumric,
L. Jonitz, H. P. Laqua, W. Leonhardt, G. Michel, F. Noke,
B. Plaum, M. Schmid, T. Schulz, K. Schwörer, M. Thumm and
M. Weissgerber: Status of the 140 GHz/10 MW CW transmission system for ECRH on the stellarator W7-X.
(23rd Symposium on Fusion Technology (SOFT), 2004-0920 till 2004-09-24, Venice).
Klinger, T.: Experimental Control of Plasma Instabilities.
(Hamiltonian Systems, Control and Plasma Physics,
2004-10-21 till 2004-10-23, Fréjus).
Koch, B., W. Bohmeyer and G. Fussmann: Angular
Dependence of Energy and Particle Fluxes in a Magnetized
Plasma. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Kasparek, W., G. Dammertz, V. Erckmann, G. Gantenbein,
E. Holzhauer, H. Kumric, H. P. Laqua, F. Leuterer,
G. Michel, U. Niethammer, B. Plaum, K. Schwörer,
D. Wagner, R. Wacker and M. Weissgerber: High-power millimetre wave transmission systems and components for electron cyclotron heating of fusion plasmas. (NATO Advanced
Research Workshop on Quasi-Optical Control of Intense
Microwave Transmission, 2004-02-17 till 2004-02-20,
Nizhny Novgorod).
Koch, B., W. Bohmeyer and G. Fussmann: Angular Dependence of Energy Particle Fluxes in a Magnetized Plasma. (2nd
German-Polish Conference on Plasma Diagnostics for
Fusion and Applications (GPPD-2004), 2004-09-08 till
2004-09-10, Cracow).
Kaufmann, M.: Plasmaphysik und Fusionsforschung I.
WS 2004/2005. Vorlesung at Universität Bayreuth.
Könies, A.: Growth and damping rates of Alfvén eigenmodes using kinetic MHD. (Joint Varenna-Lausanne
153
Lectures
International Workshop on Theory of Fusion Plasmas,
2004-08-30 till 2004-09-03, Varenna).
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
König, R., J. Chung, J. Howard and T. Klinger: First
Investigations of the Capabilities of a Time-resolved 2D
Modulated Coherence-imaging Spectrometer. (2nd GermanPolish Conference on Plasma Diagnostics for Fusion and
Applications (GPPD-2004), 2004-09-08 till 2004-09-10,
Cracow).
Lackner, K.: Magnetically confined thermonuclear grade
plasmas. (Brijuni-Conference on Matter under Extreme
Conditions, 2004-08-30 till 2004-09-01, Brijuni).
König, R., K. Grosser, D. Hildebrandt, O. Ogorodnikova,
C. von Sehren and T. Klinger: Development of actively
cooled periscopes for divertor observation during quasicontinuous operation of the W7-X stellarator. (23rd Symposium
on Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Lackner, K.: The virtual tokamak: modelling aspects of
fusion power generation. (Workshop on Computational
Approach to Energy R&D, 2004-11-11, Berlin).
Lackner, K.: Magnetically confined thermonuclear grade
plasmas. (Kolloquium, 2004-09-15, Innsbruck).
Lamalle, P., M. Mantsinen, L. Bertalot, V. Bobkov,
G. Ericsson, V. Kiptily, M. Laxaback, E. Lerche,
J.-M. Noterdaeme, M. Santala, M. Tardocchi, P. de Vries,
M. de Baar, B. Alper, P. Beaumont, S. Conroy and
K. Lawson: ICRF experiments with fundamental and second
harmonic tritium heating. (6th TFH Reporting and Planning
Meeting, 2004-04-19 till 2004-04-21, Schloss Ringberg).
König, R., O. Ogorodnikova, D. Hildebrandt, C. von Sehren,
K. Grosser, J. Baldzuhn, R. Burhenn, P. Mertens,
A. Pospieszczyk, B. Schweer, H. Schmidt and T. Klinger:
Development of cooled UV, visible and IR windows for
quasi-continuous operation of the W7-X stellarator. (15th
High Temperature Plasma Diagnostic Conference,
2004-04-19 till 2004-04-22, San Diego, CA).
Lamalle, P. U., M. J. Mantsinen, J.-M. Noterdaeme,
T. Blackman, Vl. V. Bobkov, C. Castaldo, F. Durodié,
L.-G. Eriksson, J. Heikkinen, T. Hellsten, A. Lyssoivan,
M.-L. Mayoral, F. Meo, I. Monakhov, A. Salmi,
M. I. K. Santala, S. Sharapov, D. Van Eester, B. Weyssow and
JET EFDA Contributors: Expanding the operating space of
ICRF on JET with a view to ITER. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Kornilov, V. and R. Kleiber: 3D ITG modes in toroidal plasmas within a gyrokinetic and a two-fluid description. (Joint
Varenna-Lausanne International Workshop on Theory of
Fusion Plasmas, 2004-08-30 till 2004-09-03, Varenna).
Kraus, W., B. Heinemann, H. Falter, U. Fantz, T. Franke,
P. Franzen, D. Holtum, Ch. Martens, P. McNeely, R. Riedl,
E. Speth and R. Wilhelm: RF Source Development for ITER:
Large Area H-Beam Extraction, Modifications for Long
Pulse Operation and Design of a Half Size ITER Source.
(23rd Symposium on Fusion Technology (SOFT),
2004-09-20 till 2004-09-24, Venice).
Lang, P. T.: Active ELM frequency control and mitigation in
tokamak H-mode plasmas. (IPP Institutskolloquium,
2004-12-17, Garching).
Lang, P. T.: The ASDEX Upgrade pellet injection system: a
decade of experience in flexibility. (ITER Pellet Workshop,
2004-05-18, Garching).
Krieger, K., A. Geier, J. Likonen, M. Mayer, R. Pugno,
V. Rohde, E. Vainonen-Ahlgren and ASDEX Upgrade Team:
Tungsten redistribution patterns in ASDEX Upgrade. (16th
International Conference on Plasma Surface Interactions
in Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Lang, P. T.: ELM pace making and amelioration at ASDEX
Upgrade. (2nd Hungarian Plasma Physics Workshop,
2004-04-22 till 2004-04-24, Budapest).
Lang, P. T.: ELM pace making and amelioration at ASDEX
Upgrade. (EFDA-JET Seminar, 2004-02-23, Abingdon).
Kündig, A., F. Schauer, Y. Bozhko and C. P. Dhard: Helium
refrigeration system for Wendelstein 7-X. (20th International
Cryogenic Engineering Conference, 2004-05-11 till
2004-05-14, Beijing).
Lang, P. T.: Pellets as tool for ELM pace making and amelioration. (2nd Hungarian Plasma Physics Workshop,
2004-04-23, Budapest).
Kukushkin, A. S., H. D. Pacher, D. P. Coster, G. W. Pacher
and D. Reiter: ITER divertor performance in conditions of
carbon re-erosion. (16th International Conference on Plasma
Lang, P. T., A. Kallenbach, J. Bucalossi, G. D. Conway,
A. Degeling, R. Dux, T. Eich, L. Fattorini, O. Gruber,
S. Günter, A. Herrmann, L. D. Horton, S. Kalvin, G. Kocsis,
154
Lectures
J. Lister, M. E. Manso, M. Maraschek, Y. Martin,
P. J. McCarthy, V. Mertens, R. Neu, J. Neuhauser, I. Nunes,
T. Pütterich, W. Schneider, A. C. C. Sips, W. Suttrop,
W. Treutterer, H. Zohm and ASDEX Upgrade Team:
Integrated Exhaust Scenarios with Actively Controlled
ELMs. (20th IAEA Fusion Energy Conference, 2004-11-01
till 2004-11-06, Vilamoura).
Lederer, H.: MIGENAS Project Status Overview. (MPG
Bioinformatics Meeting: Microbial Genomes, 2004-07-14,
Berlin).
Lederer, H.: Status des FP6 EU-Projekts DEISA zu
Distributed European Supercomputing ZKI-Tagung.
(Treffen des ZKI-Arbeitskreises “Supercomputing”,
2004-09-23 till 2004-09-24, RRZN Hannover).
Laqua, H., V. Erckmann, N. Marushchenko, H. Maassberg
and W. Kasparek: Elektron-Zyklotron-Wellen. (DPGFrühjahrstagung der Fachverbände Extraterrestrische
Physik, Kurzzeitphysik und Plasmaphysik, 2004-03-14 till
2004-03-18, Kiel).
Lederer, H.: Supercomputing Applications in the Max
Planck Society. (2004-08-04, Sandia National Laboratories,
Albuquerque, NM).
Lederer, H.: Zur Europäisierung des Supercomputings – das
DEISA-Projekt. (ZKI-Tagung, 2004-03-04, Stuttgart).
Laux, M., W. Schneider, B. Jüttner, M. Balden, S. Lindig,
I. Beilis and B. Djakov: Ignition and Burning of Vacuum
Arcs on Tungsten Layers. (21st International Symposium on
Discharges and Electrical Insulation in Vacuum (ISDEIV),
2004-09-27 till 2004-10-01, Yalta, Crimea Peninsula).
Leuterer, F., G. Grünwald, F. Monaco, M. Münich, H. Schütz,
F. Ryter, D. Wagner, H. Zohm, T. Franke, W. Kasparek,
G. Gantenbein, H. Hailer, G. Dammertz, H. Heidinger,
K. Koppenburg, M. Thumm, X. Yang, G. Denisov,
V. Nichporenko, V. Miasnikov and V. Zapevalov: Status of the
new ECRH system for ASDEX Upgrade. (23rd Symposium
on Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Laux, M., W. Schneider, B. Jüttner, S. Lindig, M. Mayer,
M. Balden, I. Beilis and B. Djakov: Modification of
Tungsten Layers by Arcing. (16th International Conference
on Plasma Surface Interactions in Controlled Fusion
Devices (PSI-16), 2004-05-24 till 2004-05-28, Portland,
Maine).
Leuterer, F., G. Grünwald, F. Monaco, M. Münich, H. Schütz,
F. Ryter, D. Wagner, R. Wilhelm, H. Zohm, T. Franke,
M. Thumm, G. Dammertz, H. Heidinger, K. Koppenburg,
X. Yang, W. Kasparek, G. Gantenbein, H. Hailer,
G. G. Denisov, A. Litvak and V. Zapevalov: Progress in the
New ECRH System for ASDEX Upgrade. (31st IEEE
International Conference on Plasma Science (ICOPS 2004),
2004-06-28 till 2004-07-01, Baltimore, MD).
Lebedev, S. V., V. E. Golant, F. Ryter, H. U. Fahrbach,
M. Reich, W. Suttrop, H. Zohm and ASDEX Upgrade Team:
L-H transition at low densities in ASDEX Upgrade. (6th
ITPA Meeting of the Confinement Database and Modeling
Topical Group, 2004-03-08 till 2004-03-11, Naka).
Lechon, Y., H. Cabal, M. Varela, C. Eherer, M. Baumann,
J. Düweke, T. Hamacher and G. Tosato: Global energy
model with fusion. (23rd Symposium on Fusion Technology
(SOFT), 2004-09-20 till 2004-09-24, Venice).
Levchuk, S., A. Brendel, H. Maier and H. Bolt: Development
on thin films for the control of interface properties of SiCfibre/steel composites. (9th International Conference on
Plasma Surface Engineering (PSE 2004), 2004-09-13 till
2004-09-17, Garmisch-Partenkirchen).
Lederer, H.: DEISA: Building a Virtual European
Supercomputing Facility. (34th Speedup Workshop,
2004-04-01 till 2004-04-02, Lugano).
Lindig, S., V. Alimov, H. Bolt, B. Böswirth, H. Greuner,
T. Huber, G. Matern and Plansee AG Reutte/Tirol:
Characterisation of Plasma Sprayed Boron Carbide and
Tungsten Layers for Fusion Applications. (E-MRS 2004
Spring Meeting, 2004-05-24 till 2004-05-28, Strasbourg).
Lederer, H.: The DEISA Project and its Joint Research
Activities. (2nd Annual RealityGrid Workshop, 2004-06-15
till 2004-06-16, London).
Lederer, H.: High Performance Computing: Garching
Computing Centre of the Max Planck Society.
(Supercomputer Conference 2004, 2004-06-23 till
2004-06-24, Heidelberg).
Linsmeier, C.: Carbon-containing components on fusionrelated surfaces: Thermal and ion-induced formation and
erosion. (22nd Summer School and International Symposium
on the Physics of Ionized Gases (SPIG 2004), 2004-08-23
till 2004-08-27, National Park Tara, Serbia and
Montenegro).
Lederer, H.: The MIGENAS Project: Partners, evolution,
layout. (2004-07-15, MPI for Infection Biology, Berlin).
155
Lectures
Linsmeier, C.: Chemical erosion of thin C films by deuterium ions. (IPP Workshop on Chemical Sputtering,
2004-02-12, Garching).
Maier, H.: Atomare Beschichtungsverfahren. SS 2004. Vorlesung Werkstofftechnik at Technische Universität München.
Maier, H.: Development of Tungsten Coatings for Application in Fusion Experiments. (Gordon Research Conference on High Temperature Materials, Processes &
Diagnostics, 2004-08-01 till 2004-08-06, Waterville, ME).
Linsmeier, C., A. Wiltner and K. U. Klages: Enhanced erosion of thin carbon films on metals by deuterium ions. (15th
International Workshop on Inelastic Ion Surface Collisions
(IISC-15), 2004-10-17 till 2004-10-22, Ise-Shima, Mie,
Japan).
Maier, H.: Development of Tungsten Coatings for Application
in Fusion Experiments. (5th Pacific Rim International Conference on Advanced Materials and Processing (PRICM-5),
2004-11-02 till 2004-11-05, Beijing).
Lott, F., G. F. Counsell, J. Dowling, T. Eich, A. Herrmann
and A. Kirk: Power accounting in MAST during ELMs. (16th
International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Maier, J.: Arbeitssitzungen der Gruppe Datenerfassung in
Garching und Greifswald. (Videokonferenztechnologien
und ihre Anwendungsszenarien: ”Weit entfernt und doch so
nah” (Viktas-Tag 2004), 2004-04-01, Berlin, Dresden,
Duisburg, Garching, Jena, Würzburg).
Lyssoivan, A., D. A. Hartmann, J.-M. Noterdaeme, R. Koch,
V. Bobkov, T. Blackman, F. Braun, M. Cox, P. de Vries,
H. G. Esser, H.-U. Fahrbach, J. Gafert, E. Gauthier,
O. Gehre, M. Graham, G. Haas, A. Huber, K. Lawson,
P. J. Lomas, M. Mantsinen, G. Matthews, M.-L. Mayoral,
A. Meigs, Ph. Mertens, V. Mertens, I. Monakhov,
J. Neuhauser, V. Philipps, V. Rohde, M. Santala, W. Suttrop,
A. Walden, D. Van Eester, F. Wesner, ASDEX Upgrade Team
and JET EFDA Contributors: Development of ICRF wall
conditioning technique on divertor-type tokamaks ASDEX
Upgrade and JET. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI),
2004-05-24 till 2004-05-28, Portland, Maine).
Manini, A., F. Ryter, C. Angioni, M. Apostoliceanu, A. G. Peeters,
J. Stober, G. Tardini, F. Leuterer, C. F. Maggi, D. Nishijima,
A. Stäbler, W. Suttrop, D. Wagner and ASDEX Upgrade Team:
Electron heat transport in low density H-mode plasmas in
ASDEX Upgrade. (Seminar, 2004-02-17, Lausanne).
Manini, A., F. Ryter, C. Angioni, M. Apostoliceanu,
A. G. Peeters, J. Stober, G. Tardini, F. Leuterer, C. F. Maggi,
D. Nishijima, A. Stäbler, W. Suttrop, D. Wagner and ASDEX
Upgrade Team: Experimental study of electron heat transport in NBI heated low density H-mode plasmas in ASDEX
Upgrade. (Transport Task Force Workshop on Electron
Transport, 2004-02-19 till 2004-02-20, Milano).
Lyssoivan, A., R. Koch, M. Vervier, R. Waynants, H. G. Esser,
V. Philipps, E. Gauthier, D. A. Hartmann, J.-M. Noterdaeme,
F. Braun, I. Monakhov, A. Walden, TEXTOR Team, TORE
SUPRA Team, ASDEX Upgrade Team and JET EFDA Team:
Development of ITER relevant ICRF wall conditioning
technique on European tokamaks. (10th International
Conference and School on Plasma Physics and Controlled
Fusion, 2004-09-13 till 2004-09-18, Alushta, Crimea).
Manini, A., F. Ryter, C. Angioni, A. G. Peeters and ASDEX
Upgrade Team: Recent development of the Te/Ti studies in
ASDEX Upgrade. (7th ITPA Meeting of the Confinement and
Modeling Topical Group, 2004-11-08 till 2004-11-11, Lisbon).
Maraschek, M., G. Gantenbein, T. P. Goodman, S. Günter,
D. F. Howell, F. Leuterer, A. Mück, O. Sauter, H. Zohm,
Contributors to the EFDA-JET Workprogramme and
ASDEX Upgrade Team: Active Control of MHD Instabilities
by ECCD in ASDEX Upgrade. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Maassberg, H. and C. D. Beidler: Neoclassical Transport
Modelling for Impurities in the Tracer Limit. (Workshop on
Kinetic Theory in Stellarators, 2004-09-13 till 2004-09-15,
Graz).
Maassberg, H. and C. D. Beidler: Self-consistent
Neoclassical Modelling for Tokamaks with Er included.
(Workshop on Kinetic Theory in Stellarators, 2004-09-13
till 2004-09-15, Graz).
Martin, Y. R., F. Ryter, A. Degeling, L. Horton, P. T. Lang,
J. B. Lister, A. C. C. Sips, W. Suttrop and ASDEX Upgrade
Team: Influence of edge ECH/ECCD on the ELM cycle in
ASDEX Upgrade. (20th IAEA Fusion Energy Conference,
2004-11-01 till 2004-11-06, Vilamoura).
Madani, R., C. Ionita, R. Schrittwieser and T. Klinger: First
results on a laser-heated emissive probe. (12th International
Congress on Plasma Physics, 2004-10-25 till 2004-10-29,
Nice).
Marushchenko, N. B.: High-field-side ECE Diagnostics
for W7-X: some features and advantages. (Workshop on
156
Lectures
Kinetic Theory in Stellarators, 2004-09-13 till 2004-09-15,
Graz).
Meyer-Spasche, R.: Frauen in Mathematik und Naturwissenschaften. (Herbst-Universität für Oberstufenschülerinnen
an Gymnasien, 2004-11-02, München).
Mayer, M., P. Coad, P. Wienhold and JET-EFDA Contributors:
Carbon Deposition Pattern in JET and TEXTOR. (IPP
Workshop on Chemical Sputtering, 2004-02-12, Garching).
Meyer-Spasche, R.: Spektren und Pseudospektren – Theorie,
Numerik und Anwendungen. WS 2004/2005. Vorlesung at
Technische Universität München.
Mayer, M., V. Rohde, J. Likonen, E. Vainonen-Ahlgren,
J. Chen, X. Gong, K. Krieger and ASDEX Upgrade Team:
Carbon Deposition and Deuterium Inventory in ASDEX
Upgrade. (20th IAEA Fusion Energy Conference,
2004-11-01 till 2004-11-06, Vilamoura).
Michel, G.: A fast and versatile interlock system. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Miri, A. M., C. Sihler and ASDEX Upgrade Team: Development of a stabilizer for oscillating torques in synchronous
machines. (9th International Conference on Optimization of
Electrical and Electronic Equipment (OPTIM ‘04), 200405-20 till 2004-05-22, Brasov).
Mayer, M., V. Rohde, J. Likonen, E. Vainonen-Ahlgren,
K. Krieger, X. Gong, J. Chen and ASDEX Upgrade Team:
Carbon erosion and deposition on the ASDEX Upgrade
divertor tiles. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Mishchenko, A., A. Könies and R. Hatzky: Gyrokinetic simulations with a particle discretization of the field equations.
(Joint Varenna-Lausanne International Workshop on Theory
of Fusion Plasmas, 2004-08-30 till 2004-09-03, Varenna).
McCormick, K.: Essential Elements of the High Density
H-Mode. (2nd Hungarian Plasma Physics Workshop,
2004-04-22 till 2004-04-24, Budapest).
Morisaki, T., S. Masuzaki, A. Komori, N. Ohyabu,
M. Kobayashi, Y. Feng, F. Sardei, N. Ashikawa, M. Emoto,
H. Funaba, M. Goto, K. Ida, K. Ikeda, S. Inagaki, O. Kaneko,
K. Kawahata, S. Kubo, J. Miyazawa, S. Morita, K. Nagaoka,
Y. Nagayama, H. Nakanishi, K. Narihara, K. Ohkubo, Y. Oka,
M. Osakabe, B. J. Peterson, T. Shimozuma, M. Shoji, Y. Takeiri,
S. Sakakibara, R. Sakamoto, K. Sato, K. Tanaka, K. Toi,
K. Tsumori, K. Y. Watanabe, H. Yamada, I. Yamada,
Y. Yoshimura, M. Yoshinuma, O. Motojima and LHD
Experimental Group: Local Island Divertor Experiments on
LHD. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
McCormick, K., P. Grigull, H. Ehmler, Y. Feng, G. Haas,
F. Sardei, NBI-Team, ECRH-Team and W7-AS Team: Neutral
pressure behavior for diverted discharges in the Wendelstein
7-AS stellarator. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
McCormick, K., A. Huber, C. Fuchs, C. Ingesson, J. Fink,
W. Zeidner, A. Guigon and S. Sanders: New bolometry cameras for the JET enhanced performance phase. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Mück, A., T. Goodman, M. Maraschek, F. Ryter, H. Zohm and
ASDEX Upgrade Team: NTM control via sawtooth tailoring
in ASDEX Upgrade. (DPG-Frühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und
Plasmaphysik, 2004-03-08 till 2004-03-11, Kiel).
McNeely, P.: Latest Results for RF Negative Ion Source
Development at IPP. (CCNB Meeting, 2004-06-08 till
2004-06-09, Dublin).
McTaggart, N., R. Zagorski, X. Bonnin, A. Runov,
R. Schneider, T. Kaiser, T. Rognlien and M. Umansky: 3D
edge energy transport in stellarator configuration. (16th
International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Nagel, M., S. Y. Shim and F. Schauer: Thermal and structural
analysis of the W7-X magnet heat radiation shield. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Meir, S., U. Fantz and K. Behringer: Einfluss verschiedener
Wandmaterialien auf die Vibrationsbesetzung von molekularem Wasserstoff. (DPG-Frühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und Plasmaphysik, 2004-03-08 till 2004-03-11, Kiel).
Naujoks, D.: Computer Simulation in der Plasmaphysik.
WS 2004/2005. Vorlesung at Humboldt-Universität Berlin.
Naujoks, D.: Transport and deposition of hydrocarbons. (IPP
Workshop on Chemical Sputtering, 2004-02-12, Garching).
157
Lectures
Nazikian, R., B. Alper, H. L. Berk, D. Borba, C. Boswell,
R. V. Budny, K. H. Burrell, C. Z. Cheng, E. J. Doyle,
E. Edlund, R. J. Fonck, A. Fukuyama, N. N. Gorelenkov,
C. M. Greenfield, D. J. Gupta, M. Ishikawa, R. J. Jayakumar,
G. J. Kramer, Y. Kusama, R. J. La Haye, G. R. McKee,
W. A. Peebles, S. D. Pinches, M. Porkolab, J. Rapp,
T. L. Rhodes, S. E. Sharapov, K. Shinohara, J. A. Snipes,
W. M. Solomon, E. J. Strait, M. Takechi, M. A. van Zeeland,
W. P. West, K. L. Wong, S. Wukitch and L. Zeng: Observation
of energetic particle driven modes relevant to advanced
tokamak regimes. (20th IAEA Fusion Energy Conference,
2004-11-01 till 2004-11-06, Vilamoura).
Nishijima, D., T. Sugimoto, M. Ye, T. Iwakiri, N. Yoshida,
N. Ohno and S. Takamura: Damage and gas retention of
tungsten surface with deuterium and helium mixture plasma
irradiation. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Neu, R.: Heisser als die Sonne, ITER der Weg zu einer neuen
Energiequelle. (Physikalisches Kolloquium, 2004-11-24,
Universität Tübingen).
Noterdaeme, J.-M., B. Beaumont, Ph. Lamalle, F. Durodié,
M. Nightingale, I. Monakhov, ASDEX Upgrade Team, JET
EFDA Contributors and Tore Supra Team: Matching to
Elmy Plasmas in the ICRF Domain. (23rd Symposium on
Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Noterdaeme, J.-M.: Kernreactortheorie. WS 2004. Vorlesung at Universiteit Gent.
Noterdaeme, J.-M.: Theorie van de kernreactor, vermogenverdeling. SS 2004. Vorlesung at Universiteit Gent.
Neu, R.: The physics of magnetically confined plasmas: En
route to a fusion reactor. (Graduierten Kolleg, 2004-07-09,
Tübingen).
Noterdaeme, J.-M., F. Durodié, M. Mantsinen, D. Moreau
and A. Walden: Overview of the 2005 Campaingns. (6th TFH
Reporting and Planning Meeting, 2004-04-19 till
2004-04-21, Schloss Ringberg).
Neu, R.: Plasmaphysik und Fusionsforschung. SS 2004.
Vorlesung at Universität Tübingen.
Neu, R.: Spectroscopy Data Needs of Next Generation
Devices for Magnetically Confined Fusion. (8th International Colloquium on Atomic Spectra and Oscillator
Strengths for Astrophysical and Laboratory Plasmas
(ASOS8), 2004-08-08 till 2004-08-12, Madison, WI).
Nunes, I., J. Santos, F. Salzedas, M. Manso, F. Serra,
G. D. Conway, L. D. Horton, J. Neuhauser, W. Suttrop, CFN
Team and ASDEX Upgrade Team: Density Profile Evolution
during Dynamic Processes in ASDEX Upgrade. (20th IAEA
Fusion Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Neu, R., R. Dux, A. Kallenbach, C. F. Maggi, T. Pütterich,
M. Balden, J. C. Fuchs, T. Eich, O. Gruber, A. Herrmann,
H. Maier, H. W. Müller, M. O’Mullane, R. Pugno,
I. Radivojevic, V. Rohde, A. C. C. Sips, W. Suttrop,
A. Whiteford, M. Y. Ye and ASDEX Upgrade Team:
Tungsten: An option for divertor and main chamber plasma facing components in future fusion devices. (20 th
IAEA Fusion Energy Conference, 2004-11-01 till
2004-11-06, Vilamoura).
Nührenberg, J.: Remarks on Transport in Stellarators. (Lecture, 2004-01-28 till 2004-01-29, University of Gothenburg).
Ogorodnikova, O., R. König, J. Linke and G. Pintsuk:
Thermo-stress analysis of optical materials for high heat
flux applications. (23rd Symposium on Fusion Technology
(SOFT), 2004-09-20 till 2004-09-24, Venice).
Neuner, U., R. König, O. Ogorodnikova, D. Hildebrandt,
C. von Sehren, H. Schmidt, J. Baldzuhn, R. Burhenn,
K. Grosser, P. Mertens, A. Pospieszczyk, B. Schweer and
T. Klinger: Thermal Calculations and Prototype Tests of
Diagnostics for Quasi-Continuous Operation at the W7-X
Stellarator. (2nd German-Polish Conference on Plasma
Diagnostics for Fusion and Applications (GPPD-2004),
2004-09-08 till 2004-09-10, Cracow).
Osiac, M., D. O’Connel, T. Schwarz-Selinger, T. Gans and
U. Czarnetzki: Investigations of the Plasma Boundary
Sheath Dynamics in the Afterglow of a Pulsed Inductively
Coupled rf Plasma in Hydrogen. (17th Europhysics Conference on Atomic and Molecular Physics of Ionized Gases
(ESCAMPIG), 2004-09-01 till 2004-09-05, Constanta,
Romania).
Paccagnella, R., T. Bolzonella, M. Cavinato, S. Ortolani,
G. Pautasso, W. Schneider, V. Lukash and H. Strauss: Vertical
displacement events simulations for Tokamak plasmas. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Nieckchen, P.: Das Unteilbare teilen – Atom-Modelle von
der Antike bis zur Gegenwart. (Hauptversammlung der
Max-Planck-Gesellschaft, 2004-06-24, Stuttgart).
158
Lectures
Peeters, A. G.: Theoretical understanding of observed transport phenomena. (20th IAEA Fusion Energy Conference,
2004-11-01 till 2004-11-06, Vilamoura).
Contributors to the EFDA-JET Workprogramme: Edge and
divertor physics with reversed toroidal field in JET. (16th
International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Peeters, A. G., C. Angioni, M. Apostoliceanu, G. V. Pereverzev,
F. Ryter, D. Strintzi, E. Quigley, F. Jenko, U. Fahrbach,
C. Fuchs, O. Gehre, J. Hobirk, B. Kurzan, C. F. Maggi,
A. Manini, P. J. McCarthy, H. Meister, J. Schweinzer,
J. Stober, W. Suttrop, G. Tardini and ASDEX Upgrade Team:
Understanding of the density profile shape, electron heat
transport and internal barriers observed in ASDEX Upgrade.
(20th IAEA Fusion Energy Conference, 2004-11-01 till
2004-11-06, Vilamoura).
Pochelon, A., Y. Camenen, R. Behn, A. Bortolon, A. Bottino,
S. Coda, B. P. Duval, E. Fable, T. P. Goodman,
M. A. Henderson, A. N. Karpushov, J.-M. Moret, A. Mück,
E. Nelson-Melby, L. Porte, O. Sauter, A. Scarabosio,
G. Zhuang and TCV Team: Effect of plasma shape on electron heat transport in the presence of extreme temperature
gradient variations in TCV. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Pereverzev, G. V.: Beam Tracing Technique: Applications for
RF Heating and Stability in Tokamak. (Joint VarennaLausanne International Workshop on Theory of Fusion
Plasmas, 2004-08-30 till 2004-09-03, Varenna).
Podoba, Y., K. Horvath, H. P. Laqua, J. Lingertat and
F. Wagner: Electron cyclotron resonance heating in the
WEGA stellarator. (DPG-Frühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und
Plasmaphysik, 2004-03-14 till 2004-03-18, Kiel).
Pinches, S. D.: MHD in advanced regimes – comments on
open MHD problems in advances scenarios. (EFDA-JET S2
Planning Meeting, 2004-06-08, Cadarache).
Podoba, Y., K. Horvath, H. P. Laqua, M. Otte, J. Lingertat,
D. Zhang and F. Wagner: Electron cyclotron heating at the
WEGA Stellarator. (International Conference and School on
Plasma Physics and Controlled Fusion, 2004-09-13 till
2004-09-18, Alushta, Crimea).
Pinches, S. D.: Negative helicity modes – do we see negative
poloidal mode numbers? (EFDA-JET Task Force M
Meeting, 2004-01-29, Abingdon).
Pinches, S. D.: Status of TF M data analysis – comments on
outstanding MHD analysis and publications. (EFDA-JET
JPEC Meeting, 2004-09-15, Abingdon).
Poli, E.: Kinetic effects on the dynamics of magnetic
islands. (IPP Institutskolloquium, 2004-10-15, Garching).
Poli, E., A. Bergmann, A. G. Peeters, L. Appel and
S. D. Pinches: Kinetic Calculations of the NTM Polarisation:
Reduction for Small Island Widths and Sign Reversal Near the
Diamagnetic Frequency. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Pinches, S. D., R. J. Buttery and D. Borba: Summary of significant TFM results during C8-C14. (EFDA-JET Campaign
Reporting, 2004-09-15, Abingdon).
Piosczyk, B., A. Arnold, H. Budig, G. Dammertz, O. Dumbrajs,
R. Heidinger, S. Illy, J. Jin, G. Michel, T. Rzesnicki, M. Thumm
and X. Yang: Experiments on a 170 GHz coaxial cavity gyrotron. (23rd Symposium on Fusion Technology (SOFT),
2004-09-20 till 2004-09-24, Venice).
Poulipoulis, G., G. N. Throumoulopoulos and H. Tasso:
Multi-toroidal configurations as equilibrium-flow eigenstates. (12th International Congress on Plasma Physics,
2004-10-25 till 2004-10-29, Nice).
Piosczyk, B., A. Arnold, G. Dammertz, O. Dumbrajs,
R. Heidinger, S. Illy, J. Jin, K. Koppenburg, G. Michel,
T. Rzesnicki, M. Thumm and X. Yang: Research on advanced
high power gyrotrons at FZK. (15th International Conference
on High-Power Particle Beams, 2004-07-19 till 2004-07-23,
St. Petersburg).
Pugno, R., A. Kirschner, K. Krieger, A. Kallenbach and
D. Coster: Last Results from the Hydrocarbon Puff
Experiment in the ASDEX Upgrade Divertor. (IPP
Workshop on Chemical Sputtering, 2004-02-12, Garching).
Pugno, R., A. Krieger, A. Kirschner, A. Kallenbach,
D. Coster, R. Dux, U. Fantz, J. Likonen, H. W. Müller,
J. Neuhauser, V. Rohde and E. Vainonen-Ahlgren: Parameter
dependence of carbon chemical erosion in ASDEX Upgrade
divertor IIb. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Pitts, R. A., P. Andrew, X. Bonnin, A. V. Chankin, Y. Corre,
G. Corrigan, D. Coster, I. Duran, T. Eich, S. K. Erents,
W. Fundamenski, A. Huber, S. Jachmich, G. Kirnev,
M. Lehnen, P. J. Lomas, A. Loarte, G. F. Matthews, J. Rapp,
C. Silva, M. F. Stamp, J. D. Strachan, E. Tsitrone and
159
Lectures
Pütterich, T., R. Dux, J. Gafert, A. Kallenbach, R. Neu,
R. Pugno, S.-W. Yoon and ASDEX Upgrade Team: Carbon
sources in the main chamber of ASDEX Upgrade. (IPP
Workshop on Chemical Sputtering, 2004-02-12, Garching).
a:C-H layer formation at ASDEX Upgrade. (16th International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Radtke, R., C. Biedermann and G. Fussmann: Hochgeladene Ionen in EBIT. (DPG-Frühjahrstagung der
Fachverbände Extraterrestrische Physik, Kurzzeitphysik und
Plasmaphysik, 2004-03-08 till 2004-03-11, Kiel).
Roth, J., V. Philipps and A. Loarte: Aims and Strategies of
the EU Task Force on Plasma Wall Interaction. (IPP
Workshop on Chemical Sputtering, 2004-02-12, Garching).
Rozhansky, V., E. Kaveeva, S. Voskoboynikov, D. Coster and
R. Schneider: Generation of toroidal rotation by gas puffing. Simulations of MAST experiments with B2SOLPS5.0.
(16th International Conference on Plasma Surface Interactions in Controlled Fusion Devices (PSI-16), 2004-05-24
till 2004-05-28, Portland, Maine).
Rampp, M.: A workflow engine for microbial genome
research. (Verleihung des Heinz-Billing-Preises für wissenschaftliches Rechnen, 2004-11-18, Göttingen).
Rapp, J., P. Monier-Garbet, G. F. Matthews, R. Sartori,
V. Corre, T. Eich, R. Felton, A. Huber, S. Jachmich,
H. R. Koslowski and JET EFDA Contributors: Strongly radiating type-III ELMy H-mode in JET – an integrated scenario for ITER. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Rummel, T., K. Riße and H. Ehmler: Manufacture and test of
the non-planar coils for Wendelstein 7-X. (23rd Symposium
on Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Rust, N., M. Kick and E. Speth: W7-X Neutral-BeamInjection: Transmission, Power-Load to the Duct and Inner
Vessel and Consequences of the Stellarator Stray Field. (23rd
Symposium of Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Raupp, G., G. Neu, W. Treutterer, V. Mertens, D. Zasche and
Th. Zehetbauer: Control process structure of ASDEX
Upgrade’s new control and data acquisition system. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Ryter, F., C. Angioni, A. Manini, A. G. Peeters,
M. Apostoliceanu, C. Conway, H.-U. Fahrbach and ASDEX
Upgrade Team: Investigation of TEMs in ASDEX Upgrade:
threshold and stabilisation by collisions. (10th EU-US
Transport Task Force Workshop, 2004-09-06 till
2004-09-09, Varenna).
Regler, M., U. Fantz and K. Behringer: Vergleich von
Wasserstoff- und Deuteriumentladungen in einer Quelle für
negative Ionen. (DPG-Frühjahrstagung der Fachverbände
Extraterrestrische Physik, Kurzzeitphysik und Plasmaphysik, 2004-03-08 till 2004-03-11, Kiel).
Reich, J., W. Gardebrecht, B. Hein, B. Missal, J. Tretter,
M. Wanner, F. Leher and S. Langone: Manufacture of the
vacuum vessels and the ports of Wendelstein 7-X. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Ryter, F., C. Angioni, A. G. Peeters, M. Apostoliceanu,
H. U. Fahrbach, F. Leuterer, H. Meister, W. Suttrop and
ASDEX Upgrade Team: Experimental studies of TEMs in
ASDEX Upgrade: threshold and stabilisation by collisions.
(7th ITPA Meeting of the Confinement Database and Modeling Topical Group, 2004-11-08 till 2004-11-11, Lisbon).
Riegg, S., U. Fantz, K. Behringer and WEGA Team:
Vergleich spektroskopischer Methoden zur Bestimmung von
ne und Te. (DPG-Frühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und Plasma-physik,
2004-03-08 till 2004-03-11, Kiel).
Ryter, F., C. Angioni, A. G. Peeters, M. Apostoliceanu,
H. U. Fahrbach, F. Leuterer, W. Suttrop, D. Wagner and
ASDEX Upgrade Team: Experimental studies of TEMs in
ASDEX Upgrade: threshold and stabilisation by collisions.
(Transport Task Force Workshop on Electron Transport,
2004-02-19 till 2004-02-20, Milano).
Rohde, V.: Carbon deposition measurement in ASDEX
Upgrade with quartz microbalance monitoring. (IPP
Workshop on Chemical Sputtering Workshop, 2004-02-12,
Garching).
Ryter, F., A. G. Peeters, C. Giroud, E. Joffrin, H. Leggate,
G. Maddison, M. Mantsinen, J. Ongena, D. Van Eester and
K.-D. Zastrow: Ti modulation in JET. (EFDA-JET Task
Force T Workshop, 2004-01-28 till 2004-01-30, Abingdon).
Rohde, V., M. Mayer, J. Likonen, R. Neu, R. Pugno,
T. Pütterich and E. Vainonen-Ahlgren: Carbon erosion and
160
Lectures
Sawada, A., A. Suzuki, H. Maier, F. Koch, T. Terai and
T. Muroga: Fabrication of Yttrium Oxide and Erbium Oxide
Coatings by PVD Methods. (23rd Symposium on Fusion
Technology (SOFT), 2004-09-20 till 2004-09-24, Venice).
Schwarz-Selinger, T.: Analysis of hydrogen plasmas with an
energy-dispersive mass spectrometer. (SFB 591 Kolloquium, 2004-01-16, Ruhr-Universität Bochum).
Schwarz-Selinger, T., C. Hopf and W. Jacob: Deposition
and erosion of hydrocarbon films with nitrogen containing hydrocarbon plasmas. (16th International Conference
on Plasma Surface Interactions in Controlled Fusion
Devices (PSI-16), 2004-05-24 till 2004-05-28, Portland,
Maine).
Schauer, F., H. Bau, Y. Bozhko, C. P. Dhard, U. Meyer,
M. Nagel, M. Pietsch and S. Raatz: Kryotechnik für die
Supraleiterspulen des Wendelstein 7-X. (Deutsche KälteKlima-Tagung 2004, 2004-11-17 till 2004-11-19, Bremen).
Schauer, F., M. Nagel, Y. Bozhko, M. Pietsch, F. Kufner,
F. Leher, A. Binni, H. Posselt and S. Y. Shim: Thermal insulation of the Wendelstein 7-X superconducting magnet system. (20th International Cryogenic Engineering Conference,
2004-05-11 till 2004-05-14, Beijing).
Schwarz-Selinger, T., H. D. Kang, R. Preuss and V. Dose:
Bayesian Decomposition of Quadrupole Mass Spectra.
(DPG – 68. Physikertagung und AMOP-Frühjahrstagung,
2004-03-22 till 2004-03-26, München).
Schmid, K., M. Baldwin and R. Doerner: Influence of
Beryllium plasma seeding on the erosion of Carbon. (16th
International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Schwarz-Selinger, T., H. D. Kang, R. Preuss and V. Dose:
Bayesian Decomposition of Quadrupole Mass Spectra. (24th
International Workshop on Bayesian Inference and
Maximum Entropy Methods in Science and Engineering
(MaxEnt ‘04), 2004-07-25 till 2004-07-30, Garching).
Schmidt, A., M. Balden and H. Maier: Vorlesung Werkstofftechnik. Lehrveranstaltungen ab dem 5. Fachsemester.
SS 2004. Vorlesung at Technische Universität München.
Schwarz-Selinger, T., H. D. Kang, R. Preuss and V. Dose:
Bayessche Analyse von Quadrupol-Massenspektren: Was
steckt in den Daten? (Seminar zu Aktuellen Problemen der
Technischen und Festkörperphysik, 2004-06-04, Technische
Universität Chemnitz).
Schmidt, M., H. Maassberg and N. B. Marushchenko:
Hybrid Fokker-Planck Monte Carlo Techniques. (Kinetic
Theory Workshop, 2004-09-13 till 2004-09-15, Graz).
Schwarz-Selinger, T., H. D. Kang, R. Preuss und V. Dose:
Quantitative Mass Spectrometry with the help of Bayesian
Data Analysis. (Seminar SFB 591 “Universelles Verhalten
gleichgewichtsferner Plasmen”, 2004-06-18, Bochum).
Schneider, R.: Computational physics. WS 2004/2005. Block
Lecture with Exercises at University of Technology, Helsinki.
Schwarz-Selinger, T., H. D. Kang, R. Preuss and V. Dose:
Zerlegung von Massenspektren mit Hilfe der Bayes’schen
Datenanalyse. (11. Erfahrungsaustausch Oberflächentechnologie mit Plasmaprozessen, 2004-03-02 till 2004-03-04,
Mühlleithen).
Schneider, R.: Computational Science. SS 2004. Vorlesung
at Universität Greifswald.
Schneider, R.: Edge plasma physics - a bridge between several disciplines. (2nd Hungarian Plasma Physics Workshop,
2004-04-22 till 2004-04-24, Budapest).
Schweinzer, J.: Status of the Li-beam diagnostic on ASDEX
Upgrade. (2nd Hungarian Plasma Physics Workshop,
2004-04-22 till 2004-04-24, Budapest).
Schneider, R.: Generalized coordinates, basic concepts and
applications. WS 2003/2004. Vorlesung at Universität
Greifswald.
Schwenn, U.: H.323 videoconferencing. (EFDA Remote
Participation Training & Workshop, 2004-05-17 till
2004-05-22, Budapest).
Schneider, R.: Generalized coordinates, basic concepts and
applications. WS 2004/2005. Vorlesung at Universität
Greifswald.
Schwenn, U.: 5 Jahre Videoconferencing in der MPG – Was
bleibt zu tun? (21. DV-Treffen der MPG, 2004-11-17 till
2004-11-19, Göttingen).
Schott, A. and I. Weidl: Umstellung des Regatta p690
Hochleistungsrechners am RZG vom SP Switch2 auf den
HPS (”Federation”) Switch. (AIX-AK Frühjahrstreffen 2004,
2004-03-25 till 2004-03-26, Technische Universität
Darmstadt).
Scott, B.: Self consistent transport computations in tokamak
global fluxtube geometry. (DPG-Frühjahrstagung der Fachver161
Lectures
bände Extraterrestrische Physik, Kurzzeitphysik und Plasmaphysik, 2004-03-08 till 2004-03-11, Kiel).
Tokamak Physics Activity Database. (20th IAEA Fusion
Energy Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Scott, B., T. Dannert, F. Jenko, A. Kendl, T. Ribeiro and
D. Strintzi: The Confluence of Edge and Core Turbulence
and Zonal Flows in Tokamaks. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Soddemann, T.: The MiGenAS Workflow Engine. (12th
Global Grid Forum (GGF12), 2004-09-20 till 2004-09-23,
Brussels).
Soddemann, T.: Web Services and Service Oriented
Architectures. (DELAMAN Workshop, International Expert
Meeting on Access Management, 2004-11-29 till 2004-11-30,
Nijmegen).
Sharapov, S. E., V. Kiptily, M. Mantsinen, B. Alper, D. Borba,
C. Boswell, C. D. Challis, P. de Vries, L.-G. Eriksson,
P. Lomas, M.-L. Mayoral, J.-M. Noterdaeme, S. Pinches,
P. Sandquist and A. Tuccillo: Production of fast particles
with ICRF, Transport of fast particles depending on q(r),
Further possible experiments with this method. (6th TFH
Reporting and Planning Meeting, 2004-04-19 till
2004-04-21, Schloss Ringberg).
Solano, E., Y. Corre, F. Villon, N. Hawkes, S. Jachmich,
A. Loarte, K. Guenther, A. Koroktov, M. Stamp, P. Andrew,
S. A. Arshad, T. Eich, J. Conboy, T. Bolzonella, A. Cenedese,
E. Rachlew, M. Kempenaars, R. A. Pitts and JET EFDA
Contributors: ELMs and strike point jumps. (16th
International Conference on Plasma Surface Interactions in
Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
Shimada, M., D. Campbell, R. Stambaugh, A. Polevoi,
V. Mukhovatov, N. Asakura, A. E. Costley, A. J. H. Donne,
E. J. Doyle, G. Federici, C. Gormezano, Y. Gribov,
O. Gruber, W. Houlberg, S. Ide, Y. Kamada, A. S. Kukushkin,
A. Leonard, B. Lipschultz, S. Medvedev, T. Oikawa and
M. Sugihara: Progress in physics basis and its impact on
ITER. (20th IAEA Fusion Energy Conference, 2004-11-01
till 2004-11-06, Vilamoura).
Speth, E., H. D. Falter, P. Franzen, B. Heinemann,
M. Bandyopadhyay, U. Fantz, W. Kraus, P. McNeely,
R. Riedl, A. Tanga and R. Wilhelm: Development of a RF
Source for ITER NBI: First Results with D-operation. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Shimizu, T., W. Jacob, H. Thomas, G. Morfill, T. Abe,
Y. Watanabe and N. Sato: Particle-growth in hydrogenmethane plasmas. (7th Asia-Pacific Conference on Plasma
Science and Technology (APCPST) and 17th Symposium on
Plasma Science for Materials (SPSM), 2004-06-29 till
2004-07-02, Fukuoka).
Staebler, A., A. C. C. Sips, M. Brambilla, R. Bilato, R. Dux,
O. Gruber, J. Hobirk, L. D. Horton, C. F. Maggi, A. Manini,
M. Maraschek, A. Mück, Y.-S. Na, R. Neu, G. Tardini and
ASDEX Upgrade Team: The Improved H-Mode at ASDEXUpgrade: a Candidate for an ITER Hybrid Scenario. (20th
IAEA Fusion Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Sihler, C., C. P. Käsemann, M. Huart, P. Müller and A. Sigalov:
Thyristorgesteuertes Dämpfungsmodul für Torsionsschwingungen in Synchronmaschinen. (11. Symposium
Maritime Elektrotechnik, Elektronik und Infor-mationstechnik, 2004-06-03 till 2004-06-04, Rostock).
Starke, P., U. Fantz and M. Balden: Systematic investigations of chemical erosion of carbon materials in hydrogen
and deuterium low pressure plasmas. (16th International
Conference on Plasma Surface Interactions in Controlled
Fusion Devices (PSI-16), 2004-05-24 till 2004-05-28,
Portland, Maine).
Sips, A. C. C.: Development of the Hybrid Scenario for
Tokamaks. (IPP Institutskolloquium, 2004-01-16, Garching).
Sips, A. C. C.: Advanced scenarios for ITER operation. (12th
International Congress on Plasma Physics, 2004-10-25 till
2004-10-29, Nice).
Starke, P., U. Fantz and K. Behringer: Deuteriumemission
aus Kohlenstoff bei Untersuchungen zur chemischen
Erosion. (DPG-Frühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und Plasmaphysik,
2004-03-08 till 2004-03-11, Kiel).
Sips, A. C. C., E. J. Doyle, C. Gormezano, Y. Baranov,
E. Barato, R. Budny, P. Gohil, F. Imbeaux, E. Joffrin, T. Fujita,
N. Kirneva, X. Litaudon, T. Luce, M. Murakami, J. Rice,
O. Sauter, M. Wade for the International ITB Database
Working Group, the Transport Physics Group of the ITPA and
the Steady State Operation Group of the ITPA: Study of
Advanced Tokamak Performance Using the International
Stober, J.: ASDEX Upgrade and JET – a European Step
Ladder to ITER. (DPG-Frühjahrstagung der Fachverbände
Extraterrestrische Physik, Kurzzeitphysik und Plasmaphysik,
2004-03-08 till 2004-03-11, Kiel).
162
Lectures
using tritium in JET plasmas. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Stober, J., P. Lomas, G. Saibene, Y. Andrew, P. Belo,
G. D. Conway, L. D. Horton, M. Kempenaars, H.R. Koslowski, A. Loarte, G. P. Maddison, M. Maraschek,
D. C. McDonald, A. G. Meigs, P. Monier-Garbet,
D. A. Mossessian, M. F. F. Nave, N. Oyama, V. Parail,
C. P. Perez, F. Rimini, R. Sartori, A. C. C. Sips, P. R. Thomas,
contributors to the EFDA-JET work programme and ASDEX
Upgrade Team: Small ELM regimes with good confinement
on JET and comparison to those on ASDEX Upgrade,
Alcator C-mod, and JT-60U. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Streibl, B., J. Boscary, H. Greuner, P. Grigull, J. Kisslinger,
C. Lister, B. Mendelevitch, T. Pirsch, N. Rust, S. Schweizer,
A. Vorkörper and M. Weissgerber: Manufacturing of the
W7-X divertor and wall protection. (23rd Symposium on
Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Sugiyama, K., T. Tanabe, K. Krieger, R. Neu and N. Bekris:
Tritium distribution on plasma-facing tiles from ASDEX
Upgrade. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Stoeckigt, K.: Building and maintaining GnuGK.
(TelOzConf 3, 2004-09-16, AARNet IP Telephony Working
Group, Australia).
Stoeckigt, K.: H.323 videoconferencing. (4th Annual New
Zealand Network Operators Conference (NZNOG’04),
2004-01-29 till 2004-01-30, Hamilton).
Suttrop, W., V. Hynönen, T. Kurki-Suonio, P. T. Lang,
M. Maraschek, R. Neu, A. Stäbler, G. D. Conway,
S. Hacquin, M. Kempenaars, P. J. Lomas, M. F. F. Nave,
R. A. Pitts, K.-D. Zastrow, ASDEX Upgrade Team and
Contributors to the JET-EFDA Workprogramme: Studies of
the ”Quiescent H-mode” regime in ASDEX Upgrade and
JET. (20th IAEA Fusion Energy Conference, 2004-11-01 till
2004-11-06, Vilamoura).
Stoeckigt, K.: An OpenSource Gatekeeper – GnuGK in practice. (18th APAN Meeting / QUESTnet 2004, 2004-07-02 till
2004-07-07, Cairns).
Stoeckigt, K.: Traversing H.323 audio/video through firewalls. (EFDA Remote Participation Training & Workshop,
2004-05-17 till 2004-05-22, Budapest).
Suttrop, W., T. Kurki-Suonio, A. Stäbler, G. D. Conway,
M. Maraschek, C. F. Maggi, H. Meister, R. Neu and ASDEX
Upgrade Team: Stationary ELM-free H-mode in ASDEX
Upgrade. (DPG-Frühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und Plasmaphysik,
2004-03-08 till 2004-03-11, Kiel).
Stoeckigt, K.: ViDe & GDS. (EFDA Remote Participation
Training & Workshop, 2004-05-17 till 2004-05-22,
Budapest).
Svensson, J.: Bayesian Graphical Models. (3rd Workshop on
Fusion Data Processing, Validation and Analysis, 2004-09-15
till 2004-09-17, Cadarache).
Stoeckigt, K.: Vorteile, Probleme und Erfahrungen bei
Videokonferenzen über Kontinente hinweg. (Videokonferenztechnologien und ihre Anwendungsszenarien: ”Weit
entfernt und doch so nah” (Viktas-Tag 2004), 2004-04-01,
Berlin, Dresden, Duisburg, Garching, Jena, Würzburg).
Svensson, J. and A. Dinklage: Integrated Measurements and
Analysis in Fusion Plasmas. (Institutskolloquium, 2004-01-15,
FZ Jülich).
Stoeckigt, K. and U. Schwenn: Experiences with an
OpenSource Solution for the H.323 Firewall Issues.
(SURA/ViDe 6th Annual Video Workshop, 2004-03-22 till
2004-03-25, Indianapolis, IN).
Svensson, J., M. von Hellermann and R. König: Neural
Network Application at the JET Tokamak. (Progress in
Electromagnetic Research Symposium (PIERS 2004),
2004-03-28 till 2004-03-31, Pisa).
Storck, D., K.-D. Zastrow, M. Adams, L. Bertalot, J.H. Brzowski, C. D. Challis, S. Conroy, M. de Baar, P. de
Vries, G. Ericsson, L. Garzotti, G. Gorini, N. C. Hawkes,
T. C. Hender, E. Joffrin, V. Kiptily, P. Lamalle, A. Loarte,
P. J. Lomas, J. Mailoux, M. Mantsinen, D. C. McDonald,
A. Murari, R. Neu, J. Ongena, S. Popovichev, G. Saibene,
M. Santala, S. Sharapov, M. Stamp, J. Stober,
I. Voitsekhovitch, H. Weisen, A. D. Whiteford, V. Yavorskij,
A. Zabolotsky and JET EFDA Contributors: Overview of
transport, fast particle and heating and current drive physics
Tabarés, F. L., D. Tafalla, V. Rohde, M. Stamp,
G. F. Matthews, G. Esser, V. Philipps, R. Doerner and
M. Baldwin: Studies of a-C:D film inhibition by nitrogen
injection in laboratory plasmas and divertors. (16th
International Conference on Plasma Surface Interactions
in Controlled Fusion Devices (PSI-16), 2004-05-24 till
2004-05-28, Portland, Maine).
163
Lectures
Tanga, A.: The first ITER NB Injector and the ITER NB Test
Facility: Design. (CCNB Meeting, 2004-11-30 till 2004-12-02,
Madrid)
advanced high-power gyrotrons for nuclear fusion plasma
heating. (NATO Advanced Research Workshop on QuasiOptical Control of Intense Microwave Transmission, 200402-17 till 2004-02-20, Nizhny Novgorod).
Tanga, A., M. Bandyopadhyay, H. Falter, U. Fantz,
P. Franzen, B. Heinemann, W. Kraus, P. McNeely, R. Riedl,
E. Speth and R. Wilhelm: Diagnostics and Modeling of the
Plasma in BATMAN Radio Frequency Ion Source. (23rd
Symposium on Fusion Technology (SOFT), 2004-09-20 till
2004-09-24, Venice).
Thumm, M., G. Dammertz, V. Erckmann, G. Gantenbein,
W. Kasparek, H. P. Laqua, G. Michel, W. Leonhardt,
G. Müller, G. Neffe and M. Schmid: Status of the 10 MW
140 GHz, CW ECRH system for the stellarator W7-X.
(31st IEEE International Conference on Plasma Science
(ICOPS 2004), 2004-06-28 till 2004-07-01, Baltimore, MD).
Tanga, A.; Bandyopadhyay, M. and NBI Group: Plasma
source diagnostics and modelling. (CCNB Meeting,
2004-11-30 till 2004-12-02, Madrid).
Toussaint, U. von: Online evaluation of fusion diagnostics.
(3rd Workshop on Fusion Data Processing, Validation and
Analysis, 2004-09-15 till 2004-09-17, Cadarache).
Tasso, H. and G. N. Throumoulopoulos: Lyapunov stability
of certain MHD systems. (International Sherwood Fusion
Theory Conference, 2004-04-26 till 2004-04-28, Missoula,
MO).
Toussaint, U. von, S. Gori and V. Dose: Denoising of
Speckle Data with Bayesian Neural Networks. (24th
International Workshop on Bayesian Inference and
Maximum Entropy Methods in Science and Engineering
(MaxEnt ‘04), 2004-07-25 till 2004-07-30, Garching).
Tasso, H. and G. N. Throumoulopoulos: Lyapunov stability
of certain MHD systems. (Workshop on Non-linear Stability
and Instability for Kinetic and Fluid Models in Astrophysics
and Plasmaphysics, 2004-09-06 till 2004-09-10, Bayreuth).
Treutterer, W., T. Zehetbauer, G. Neu, V. Mertens, G. Raupp
and D. Zasche: Plasma feedback controller reorganisation
for ASDEX Upgrade’s new CODAC. (23rd Symposium on
Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Terry, J. L., S. J. Zweben, O. Grulke, B. LaBombard,
M. J. Greenwald, T. Munsat and B. Veto: Comparisons of
Edge/SOL Turbulence in L- and H-mode Plasmas of Alcator
C-Mod. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Tsalas, M., N. Tsois, V. Rohde, J. Neuhauser and ASDEX
Upgrade Team: Langmuir probe measurements in the lower
x-point vicinity of the ASDEX Upgrade divertor tokamak.
(16th International Conference on Plasma Surface Interactions in Controlled Fusion Devices (PSI-16), 2004-05-24
till 2004-05-28, Portland, Maine).
Thomsen, H., T. Klinger, R. König, A. Alonso and C. Hidalgo:
Edge plasma turbulence imaging and application of pattern
recognition techniques. (2nd German-Polish Conference on
Plasma Diagnostics for Fusion and Applications (GPPD2004), 2004-09-08 till 2004-09-10, Cracow).
Turkin, Y.: Simulation of toroidal current evolution for
W7-X. (IPP-Theory-Week Workshop, 2004-11-08 till
2004-11-12, Schloss Ringberg).
Throumoulopoulos, G. N. and H. Tasso: Hall-MHD axisymmetric equilibria with flow. (International Sherwood Fusion
Theory Conference, 2004-04-26 till 2004-04-28, Missoula,
MO).
Vainonen-Ahlgren, E., J. Likonen, T. Renvall, V. Rohde,
R. Neu, M. Mayer, R. Pugno, K. Krieger and ASDEX
Upgrade Team: Studies on 13C transport and deposition at
ASDEX Upgrade. (16th International Conference on Plasma
Surface Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Thumm, M., A. Arnold, E. Borie, G. Dammertz,
R. Heidinger, S. Illy, J. Jin, K. Koppenburg, G. Michel,
B. Piosczyk, T. Rzesnicki, D. Wagner and X. Yang: Advanced
high power gyrotrons for ECRH & CD applications in
fusion plasmas. (31st IEEE International Conference on
Plasma Science (ICOPS 2004), 2004-06-28 till 2004-07-01,
Baltimore, MD).
Verhoeven, A. G. A., W. A. Bongers, A. Bruschi, S. Cirant,
I. Danilov, B. S. Q. Elzendoorn, J. W. Genuit, M. F. Graswinckel,
R. Heidinger, W. Kasparek, K. Kleefeldt, O. G. Kruijt, S. Nowak,
B. Piosczyk, B. Plaum, T. C. Plomp, D. M. S. Ronden and
H. Zohm: Design of the mm-wave system of the ECRH upper
launcher for ITER. (23rd Symposium on Fusion Technology
(SOFT), 2004-09-20 till 2004-09-24, Venice).
Thumm, M., A. Arnold, O. Drumm, J. Jin, G. Michel,
T. Rzesnicki, D. Wagner and X. Yang: QO mode converters in
164
Lectures
Viebke, H., T. Rummel, K. Riße, R. Schroeder and R. Winter:
Fabrication of the planar coils for Wendelstein 7-X.
(23rd Symposium on Fusion Technology (SOFT), 2004-09-20
till 2004-09-24, Venice).
T. Rummel, C. Sborchia, F. Schauer, R. Schröder, U. Schultz,
S. Schweizer, J. Simon-Weidner, M. Sochor, L. Sonnerup,
B. Streibl, J. Tretter, M. Thumm, H. Viebke, M. Wanner,
L. Wegener, M. Weissgerber, A. Werner and M. Winkler:
Physics, Technologies and Status of the Wendelstein 7-X
Device. (20th IAEA Fusion Energy Conference, 2004-11-01
till 2004-11-06, Vilamoura).
Wagner, F.: Energie im Allgemeinen und Fusion im
Besonderen. (Vortrag, 2004-05-13, Neustadt a.d. Aisch).
Wagner, F.: Fusion und die im TI Greifswald Arbeiten.
(Kolloquiumsvortrag, 2004-05-28, Fachhochschule Stralsund).
Wegener, L.: Technologische Herausforderungen beim
Aufbau des Fusionsexperimentes Wendelstein 7-X.
(11. Symposium Maritime Elektrotechnik, Elektronik und
Informationstechnik, 2004-06-03 till 2004-06-04, Rostock).
Wagner, F.: Fusionstechnik – eine künftige Option der Elektroenergiewandlung. (6. Gastvortrag im Rahmen der Reihe
”Aktuelle Probleme der elektrischen Energietechnik”,
2004-05-17, Technische Universität Ilmenau).
Wegener, L. and W7-X Team: Wendelstein 7-X at the transition to assembly. (23rd Symposium on Fusion Technology
(SOFT), 2004-09-20 till 2004-09-24, Venice).
Wagner, F.: Köpfe und Karriere. (IHK Unternehmertag,
2004-09-30, Neubrandenburg).
Weisen, H., C. Angioni, A. Bortolon, C. Bourdelle,
L. Carraro, I. Coffey, R. Dux, X. Garbet, L. Garzotti,
C. Giroud, N. Hawkes, D. Kalupin, H. Leggate, P Mantica,
M. Mattioli, D. Mazon, D. McDonald, R. Neu, V. Parail,
M. E. Puiatti, M. Tokar, M. Valisa, M. Valovic, J. Weiland,
L. Zabeo, A. Zabolotsky, K.-D. Zastrow and Contributors to
the JET-EFDA Workprogramme: Anamalous particle and
impurity transport in JET. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Wagner, F.: Magnetic Confinement. (Vorlesung Sommerakademie, 2004-07-16, Greifswald).
Wagner, F.: Physics, technologies and status of the
Wendelstein 7-X device. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Wagner, F.: Progress in Fusion Research. (Kolloquiumsvortrag, 2004-04-19, Dresden).
Weller, A.: Hoch-Beta Plasmen im W7-AS Stellarator.
(Kolloquium ”Experimentelle Plasmaphysik”, 2004-11-16,
Humboldt-Universität Berlin).
Wagner, F.: Research on Nuclear Fusion in Greifswald.
(Vorlesung Sommerakademie, 2004-07-16, Greifswald).
Weller, A.: Interaction of fast ions with Alfvén modes in the
W7-AS stellarator. (12th European Fusion Physics Workshop, 2004-12-06 till 2004-12-08, Witney).
Wagner, F.: Stand und Zukunft der Fusionsforschung mit
magnetischem Einschluss. (Wiener Physikalisches Kolloquium, 2004-06-14, Technische Universität Wien).
Weller, A.: Soft X-Ray Emission Diagnostics of Magnetically Confined Hot Plasmas. (2nd German-Polish Conference on Plasma Diagnostics for Fusion and Applications
(GPPD-2004), 2004-09-08 till 2004-09-10, Cracow).
Wagner, F.: Wendelstein Stellarators. (Seminar, 2004-06-17,
Kurchatov Institute, Moscow).
Wagner, F., T. Andreeva, J. Baldzuhn, A. Benndorf, H. Bolt,
J. Boscary, H. S. Bosch, T. Bräuer, R. Brakel, P. Brand,
A. Cardella, M. Czerwinski, C. Damiani, G. Dammertz,
A. Dübner, H. Ehmler, F. Elio, M. Endler, V. Erckmann,
J. H. Feist, M. Fillunger, G. Gantenbein, W. Gardebrecht,
M. Gasparotto, B. Giesen, H. Greuner, H. Greve, P. Grigull,
H. Grote, E. Harmeyer, H. J. Hartfuss, D. Hartmann,
B. Hein, B. Heinemann, D. Holtum, M. Huguet, F. Hurd,
N. Jaksic, W. Kasparek, J. Kisslinger, T. Klinger, J. Knauer,
R. Krampitz, H. Laqua, H. Lentz, K. Liesenberg, J. Maier,
R. Maix, B. Mendelevitch, G. Michel, M. Nagel, D. Naujoks,
H. Niedermeyer, C. Nührenberg, A. Opitz, G. Pfeiffer,
M. Pietsch, J. Reich, K. Risse, P. Rong, K. Rummel,
Weller, A., S. Mohr and C. Junghans: Concepts of x-ray
diagnostics for Wendelstein 7-X. (15th Topical Conference
on High-Temperature Plasma Diagnostics, 2004-04-19 till
2004-04-22, San Diego,CA).
Werner, A.: Long-time integration of Magnetic Diagnostics.
(3rd Workshop on Fusion Data Processing, Validation and
Analysis, 2004-09-15 till 2004-09-17, Cadarache).
Werner, A., J. Geiger, A. Weller and S. Zegenhagen: Magnetic
Diagnostics for long pulse operation in Wendelstein 7-X.
(15th Topical Conference on High Temperature Plasma
Diagnostics, 2004-04-19 till 2004-04-25, San Diego, CA).
165
Lectures
Wienhold, P., A. Litnovski, V. Phillips, B. Schweer, G. Sergienko,
P. Oelhafen, M. Ley, W. Schneider, D. Hildebrandt, M. Laux,
M. Rubel and B. Emmoth: Exposition von MolybdänSpiegeln am Plasmarand von TEXTOR. (DPG-Frühjahrstagung der Fachverbände Extraterrestrische Physik, Kurzzeitphysik und Plasmaphysik, 2004-03-08 till 2004-03-11,
Kiel).
Confinement Relevant Alfvén Instabilities in Wendelstein
7-AS. (20th IAEA Fusion Energy Conference, 2004-11-01
till 2004-11-06, Vilamoura).
Yamada, H., J. H. Harris, A. Dinklage, E. Ascasibar, F. Sano,
S. Okamura, J. Talmadge and U. Stroth: Confinement Study
of Net-Current Free Toroidal Plasmas Based on Extended
International Stellarator Database. (20th IAEA Fusion
Energy Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Wienhold, P., A. Litnovski, V. Phillips, B. Schweer,
G. Sergienko, P. Oelhafen, M. Ley, W. Schneider,
D. Hildebrandt, M. Laux, M. Rubel and B. Emmoth: Exposure
of Molybdenum Mirrors in the Scrape-off Layer of TEXTOR. (16th International Conference on Plasma Surface
Interactions in Controlled Fusion Devices (PSI-16),
2004-05-24 till 2004-05-28, Portland, Maine).
Yamamoto, S., K. Toi, N. Nakajima, S. Ohdachi, S. Sakakibara,
C. Nührenberg, K. Y. Watanabe, S. Murakami, M. Osakabe,
N. Ohyabu, K. Kawahata, M. Goto, Y. Takeiri, K. Tanaka,
T. Tokuzawa, K. Narihara, Y. Narushima, S. Masuzaki,
S. Morita, I. Yamada, H. Yamada and LHD Experimental
Group: Configuration Dependence of Energetic Ion Driven
Alfvén Eigenmodes in the Large Helical Device. (20th IAEA
Fusion Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Wilhelm, R.: 50 Jahre Plasmaphysik – Ein Rückblick. (IPP
Institutskolloquium, 2004-08-23, Garching).
Wilhelm, R.: Plasmaphysik I. WS 2003/2004. Vorlesung at
Technische Universität München.
Yang, X., G. Dammertz, R. Heidinger, K. Koppenburg,
F. Leuterer, B. Piosczyk, D. Wagner and M. Thumm: Design
of an ultra-broadband single-disk output window for a frequency step-tunable 1 MW gyrotron. (23rd Symposium on
Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Wilhelm, R.: Plasmaphysik II. SS 2004. Vorlesung at
Technische Universität München.
Wiltner, A., T. Jacob and C. Linsmeier: Reaction and dissolution of carbon films on Ni (111), Ni (100) and Fe (110).
(Symposium on Surface Science 2004 (3S’04), 2004-02-29
till 2004-03-06, St. Christoph am Arlberg).
Ye, M. E.: Fundamental investigations on plasma-surface
interaction in divertor plasma simulator. (Kolloquium,
2004-01-28, Humboldt Universität Berlin).
Wright, J. C., L. A. Berry, P. T. Bonoli, D. B. Batchelor,
E. F. Jaeger, M. D. Carter, E. D. Azevedo, C. K. Phillips,
H. Okuda, R. W. Harvey, D. N. Smithe, J. R. Myra,
D. A. D’Ippolito, M. Brambilla and R. J. Dumont: Nonthermal
Particle and Full-Wave Diffraction Effects on Heating and
Current Drive in the ICRF and LHRF Regimes. (20th IAEA
Fusion Energy Conference, 2004-11-01 till 2004-11-06,
Vilamoura).
Ye, M. E., H. Maier, H. Bolt, V. Rohde, A. Herrmann,
R. Neu, J. Neuhauser and ASDEX Upgrade Team: W-coated
CFC Limiter Tests in ASDEX Upgrade. (Japan-EUMeeting on Refractory Alloys, 2004-03-15 till 2004-03-16,
Garching).
Ye, M. E., H. Maier, A. Herrmann, V. Rohde, H. Bolt,
R. Neu, J. Neuhauser and ASDEX Upgrade Team: Tungsten
Limiter Tests in ASDEX Upgrade. (16th International
Conference on Plasma Surface Interactions in Controlled
Fusion Devices (PSI-16), 2004-05-24 till 2004-05-28,
Portland, Maine).
Wright, J. C., P. T. Bonoli, C. K. Phillips, M. Brambilla and
E. D’Azevedo: An analysis of lower hybrid wave diffraction
and focusing with a 2D toroidal full-wave code.
(International Sherwood Fusion Theory Conference,
2004-04-26 till 2004-04-28, Missoula,MO).
Zaccaria, P., A. Antipenkov, V. Antoni, A. Coniglio, S. Dal Bello,
C. Day, M. Dremel, R. Hemsworth, T. Jones, A. Mack,
D. Marcuzzi, A. Masiello, M. Pillon, S. Sandri, E. Speth,
A. Tanga and P. L. Mondino: Maintenance schemes for the
ITER neutral beam injector test facility. (23rd Symposium on
Fusion Technology (SOFT), 2004-09-20 till 2004-09-24,
Venice).
Wünderlich, D., U. Fantz and K. Behringer: Anwendung
eines Stoß-Strahlungsmodells mit nichtlinearem Solver zur
Diagnostik an Niederdruckplasmen. (DPG-Frühjahrstagung
der Fachverbände Extraterrestrische Physik, Kurzzeitphysik
und Plasmaphysik, 2004-03-08 till 2004-03-11, Kiel).
Yakovenko, Y. V., Y. I. Kolesnichenko, V. V. Lutsenko, A. Weller,
A. Werner, S. Zegenhagen, J. Geiger and A. Dinklage:
166
Lectures
Zakharov, L. E., S. N. Gerasimov and G. V. Pereverzev:
Equilibrium reconstruction and tokamak simulations with
ESC-ASTRA. (International Sherwood Fusion Theory
Conference, 2004-04-26 till 2004-04-28, Missoula, MO).
Zarnstorff, M., A. Weller, J. Geiger, E. Fredrickson,
S. Hudson, J. Knauer, A. Reiman, A. Dinklage, G. Fu, L. Ku,
D. Monticello, C. Nührenberg, A. Werner, W7-AS Team and
NBI-Group: Equilibrium and Stability of High-Beta
Plasmas in Wendelstein 7-AS. (20th IAEA Fusion Energy
Conference, 2004-11-01 till 2004-11-06, Vilamoura).
Zehetbauer, Th., D. Zasche, T. Vijverberg, R. Cole,
K. Lüddecke, G. Neu, G. Raupp and W. Treutterer:
Commissioning tests for control processes in ASDEX
Upgrade’s new CODAC. (23rd Symposium on Fusion Technology (SOFT), 2004-09-20 till 2004-09-24, Venice).
Zohm, H.: Large scale instabilities in magnetically confined
plasmas. (Kolloquium, 2004-04-21, Katlenburg-Lindau).
Zohm, H.: Neues von der Fusionsforschung mit magnetischem Einschluss. (Kolloquium, 2004-07-04, Bonn).
Zohm, H.: Recent results from ASDEX Upgrade. (Seminar,
2004-02-10, San Diego,CA).
Zohm, H.: Plasmaphysik. SS 2004. Vorlesung at Universität
München.
Zohm, H. and ASDEX Upgrade Team: Recent results from
ASDEX Upgrade. (RFX Seminar, 2004-05-03, Padova).
Zohm, H. and S. Günter: Small and large scale instabilities
in magnetically confined plasmas at low collisionality.
(Solar System Seminar S3, International Max Planck
Research School, 2004-04-21, Katlenburg-Lindau).
167
Laboratory Reports
Internal IPP-Reports
IPP 9/135
Bauer, M.: Bestimmung der Wachstumsprecursoren für
amorphe Kohlenwasserstoffschichten in gepulsten Methanplasmen.
IPP 1/332
Merkl, D.: “Current Holes” and other Structures in Motional
Stark Effect Measurements.
IPP 10/26
Bosch, H.-S. (Ed.): ASDEX Upgrade Results. Publications
and Conference Contributions. Period 1/03 to 12/03.
IPP 1/333
Bosch, H.-S. (Ed.): ASDEX Upgrade Results. Publications
and Conference Contributions. Period 1/03 to 12/03.
IPP 10/27
Dux, R.: Impurity Transport in Tokamak Plasmas.
IPP II/7
Mück, A.: Study of the Sawtooth Instability and its Control
in the ASDEX Upgrade Tokamak.
IPP 13/3
Feng, Y., R. Liu, J. Kisslinger and F. Sardei: Connection
length calculation for the divertor relevant vacuum magnetic
configurations of W7-X.
IPP II/8
Bosch, H.-S. (Ed.): ASDEX Upgrade Results. Publications
and Conference Contributions. Period 1/03 to 12/03.
IPP 15/5
Schröder, C.: Experimental investigations on drift waves in
linear magnetized plasmas.
IPP 4/283
Encheva, A.: Design and performance of an inter-pulse
cooled calorimeter for low power measurements.
IPP 16/1
Hamacher, T. and J. Sheffield: Development of Fusion
Power: What role could fusion play in transitional and developing countries?
IPP 4/284
Bandyopadhyay, M.: Studies of an inductively coupled negative hydrogen ion radio frequency source through simulations and experiments.
IPP 16/3
Albrecht, A.: Der Energiemarkt und dessen technoökonomische Modellierung – Potentiale zukünftiger Technologien.
IPP 5/105
Pfirsch, D. and D. Correa-Restrepo: New method of deriving local energy and momentum-conserving Maxwell-collisionless drift-kinetic and gyrokinetic theories: basic theory.
IPP 17/1
Popescu, C.: Processing and Characterisation of SiC-Fibre
Reinforced Cu-Matrix Composites.
IPP 5/106
Correa-Restrepo, D. and D. Pfirsch: New method of deriving local energy and momentum-conserving Maxwell-collisionless drift-kinetic and gyrokinetic theories: conservation
laws and their structures.
IPP 17/2
Balden, M.: Assessment of the Si content of Si impregnated
Carbon-Carbon Fibre composite.
IPP 5/107
Correa-Restrepo, D. and D. Pfirsch: The electromagnetic gauge
in the variational formulation of kinetic and other theories.
IPP 17/3
Juan Pardo, M. E.: Characterisation and Mitigation of
Chemical Erosion of Doped Carbon Materials.
IPP 5/108
Bosch, H.-S. (Ed.): ASDEX Upgrade Results. Publications
and Conference Contributions. Period 1/03 to 12/03.
External Reports
INDC(NDS)-457
Fantz, U. and D. Wünderlich: Franck-Condon factors, transition probabilities and radiative lifetimes for hydrogen molecules and their isotopomeres. IAEA, Vienna.
IPP 5/109
McGuinness, H. and E. Strumberger: GEOM: Discrete
Geometric Mapping for Toroidal Devises.
IPP 5/111
Meyer-Spasche, R.: On Difference Schemes for Quasilinear
Evolution Problems.
168
Teams
ASDEX Upgrade Team
R. Akers*, C. Brickley*, A. Sykes*, M. J. Walsh*,
S. M. Kaye*, C. Bush*, D. Hogewei*, Y. Martin*, A. Cote*,
G. Pacher*, J. Ongena*, F. Imbeaux*, G. T. Hoang*,
S. Lebedev*, A. Chudnovskiy*, V. Leonov*.
C. Angioni, M. Apostoliceanu, C. V. Atanasiu*, M. Balden,
G. Becker, W. Becker, K. Behler, K. Behringer,
A. Bergmann, R. Bilato, I. Bizyukov, V. Bobkov,
T. Bolzonella*, D. Borba*, M. Brambilla, F. Braun,
A. Buhler, A. Chankin, J. Chen, S. Cirant*, G. Conway,
D. P. Coster, T. Dannert, K. Dimova, R. Drube, R. Dux,
T. Eich, K. Engelhardt, H.-U. Fahrbach, U. Fantz,
L. Fattorini*, M. Foley*, J. C. Fuchs, J. Gafert, K. Gál,
G. Gantenbein*, M. García Muñoz, O. Gehre, L. Gianonne,
O. Gruber, S. Günter, G. Haas, D. Hartmann, B. Heinemann,
A. Herrmann, J. Hobirk, H. Hohenöcker, L. Horton,
M. Huart, V. Igochine, A. Jacchia*, F. Jenko, A. Kallenbach,
S. Kálvin*, O. Kardaun, M. Kaufmann, M. Kick,
G. Kocsis*, H. Kollotzek, C. Konz, W. Kraus, K. Krieger,
T. Kurki-Suonio*, B. Kurzan, K. Lackner, P. T. Lang,
P. Lauber, M. Laux, F. Leuterer, J. Likonen*, A. Lohs,
A. Lorenz, A. Lyssoivan*, C. Maggi, H. Maier, K. Mank,
A. Manini, M.-E. Manso*, P. Mantica*, M. Maraschek,
P. Martin*, M. Mayer, P. McCarthy*, H. Meister,
S. Menmuir*, F. Meo*, P. Merkel, R. Merkel, D. Merkl,
V. Mertens, H. Meyer*, F. Monaco, A. Mück, H. W. Müller,
M. Münich, H. Murmann, Y.-S. Na, R. Narayanan, G. Neu,
R. Neu, J. Neuhauser, D. Nishijima, J.-M. Noterdaeme,
I. Nunes*, M. Pacco-Düchs, G. Pautasso, A. G. Peeters,
G. Pereverzev, S. Pinches, E. Poli, E. Posthumus-Wolfrum,
T. Pütterich, R. Pugno, E. Quigley*, I. Radivojevic,
G. Raupp, M. Reich, T. Ribeiro*, R. Riedl, V. Rohde,
J. Roth, F. Ryter, W. Sandmann, J. Santos*, G. Schall,
H.-B. Schilling, J. Schirmer, W. Schneider, G. Schramm,
J. Schweinzer, S. Schweizer, B. Scott, U. Seidel, F. Serra*,
C. Sihler, A. Silva*, A. C. C. Sips, E. Speth, A. Stäbler,
K.-H. Steuer, J. Stober, B. Streibl, D. Strintzi,
E. Strumberger, W. Suttrop, G. Tardini, C. Tichmann,
W. Treutterer, M. Troppmann, M. Tsalas*, H. Urano,
P. Varela*, D. Wagner, F. Wesner, R. Wolf, E. Würsching,
M. Y. Ye, Q. Yu, B. Zaniol*, D. Zasche, T. Zehetbauer,
M. Zilker, H. Zohm.
NBI-Group
B. Heinemann, R. Kairys, S. Knoll, P. McNeely, O. Raths,
R. Riedl, B. Rogge, P. Rong, N. Rust, R. Schröder, E. Speth.
NBI-Team
M. Bandyopadhyay, A. Encheva, H.-D. Falter, U. Fantz,
Th. Franke, P. Franzen, M. Fröschle, B. Heinemann,
D. Holtum, M. Kick, W. Kraus, Ch. Martens, P. McNeely,
R. Riedl, N. Rust, E. Speth, A. Stäbler, A. Tanga,
R. Wilhelm.
W7-AS Team
T. Andreeva, S. Bäumel, J. Baldzuhn, C. Beidler,
T. Bindemann, R. Brakel, H. Braune, R. Burhenn, J. Chung,
A. Dinklage, A. Dodhy, H. Ehmler, M. Endler, V. Erckmann,
Y. Feng, M. Fink, C. Franck, F. Gadelmeier, J. Geiger,
L. Giannone, P. Grigull, O. Grulke, E. Harmeyer,
H.-J. Hartfuss, D. Hartmann, F. Herrnegger, M. Hirsch,
E. Holzhauer*, K. Horvath, Yu. L. Igitkhanov, R. Jaenicke,
F. Karger, W. Kasparek*, M. Kick, J. Kisslinger, T. Klinger,
S. Klose, J. Knauer, R. König, G. Kühner, A. Kus, H. Laqua,
K. D. Lee, J. Lingertat, R. Liu, H. Maaßberg, S. Marsen,
N. B. Marushchenko, K. McCormick, G. Michel,
G. Müller*, R. Narayanan, U. Neuner, M. Otte,
M. G. Pacco-Düchs, E. Pasch, A. Pasternak,
E. Polunovsky*, A. Reichert, N. Ruhs, J. Saffert,
E. Sallander, J. Sallander, F. Sardei, F. Schneider,
M. Schmidt, C. Schröder, M. Schubert, A. Stark,
J. Svensson, H. Thomsen, Y. Turkin, F. Volpe, F. Wagner,
A. Weller, A. Werner, H. Wobig, E. Würsching, D. Zhang,
D. Zimmermann.
ECRH-Group
H. Braune, V. Erckmann, F. Hollmann, L. Jonitz, H. Laqua,
G. Michel, F. Noke, F. Purps, T. Schulz, M. Weissgerber.
ITPA H-Mode Database Working Group
J. A. Snipes*, M. Greenwald*, L. Sugiyama*,
O. J. W. F. Kardaun, F. Ryter, A. Kus, J. Stober,
J. C. DeBoo*, C. C. Petty*, G. Bracco*, M. Romanelli*,
Z. Cui*, Y. Liu*, J. G. Cordey*, K. Thomsen*,
D. C. McDonald*, Y. Miura*, K. Shinohara*, K. Tsuzuki*,
Y. Kamada*, T. Takizuka*, H. Urano*, M. Valovic*,
*external authors
169
Appendix
Appendix
How to reach IPP in Garching
172
Appendix
How to reach Greifswald Branch Institute of IPP
173
Appendix
Organisational structure
of Max-Planck-Institut für Plasmaphysik
Max Planck Society
Advisory Board
Prof. Dr. R. Parker
(Chairman)
Supervisory Board
Prof. Dr. P. Gruss
(Chairman)
Board of Scientific
Directors
Prof. Dr. A. Bradshaw
(Chairman)
Directorate
Prof. Dr. A. Bradshaw
Prof. Dr. M. Kaufmann
Dr.-Ing. K. Tichmann
Prof. Dr. F. Wagner
Scientists
Representative Council
Dr. R. Neu
Scientific-technical
Bureau
Dr. W. Dyckhoff
Offices of the
administrative
Director
Steering Committee
Dr. U. Finzi
(Chairman)
Staff
Representative Councils
G. Hussong (Garching)
Dr. H. Grote (Greifswald)
Experimental Plasma
Physics 1
Prof. Dr. M. Kaufmann
Experimental Plasma
Physics 3
Prof. Dr. F. Wagner
Computer Center
Garching
Dipl.-Inf. S. Heinzel
Experimental Plasma
Physics 2
Prof. Dr. H. Zohm
Experimental Plasma
Physics 5
Prof. Dr. T. Klinger
Central
Technical Services
Dr. U. Schneider
Experimental Plasma
Physics 4
Prof. Dr. K. Behringer
Stellarator Physics
Prof. Dr. J. Nührenberg
Administration
General Services
Dr. M. Winkler
Tokamak Physics
Prof. Dr. S. Günter
Prof. Dr. K. Lackner
Technology
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Enterprise
WENDELSTEIN 7-X
Prof. Dr. F. Wagner
Administration
Greifswald
Dr. W. König
Project Coordination
Dr. H.-S. Bosch
Basic Device
Dr. M. Wanner
Materials Science
Prof. Dr. H. Bolt
System Engineering
Dr. M. Gasparotto
Assembly
Dr. L. Wegener
Surface Physics
Prof. Dr. V. Dose
Prof. Dr. J. Küppers
Physics
Prof. Dr. T. Klinger
Garching
Greifswald
174
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Further Information
This work was performed under the terms
of the agreement between Max-PlanckInstitut für Plasmaphysik and the European
Atomic Energy Community to conduct joint
research in the field of plasma physics.
All rights reserved.
Reproduction – in whole or in part – subject to prior written consent of IPP and
inclusion of the names of IPP and the
author.