Download Evolution of interplanetary coronal mass ejections for different solar

Evolution of
Interplanetary Coronal Mass Ejections
for Different Solar Wind Conditions
Dasso S.1,2, Gulisano A.M.1, Demoulin P.3, Ruiz M.E.1 & Marsch E.4
1
Instituto de Astronomía y Física del Espacio (IAFE), Universidad de Buenos Aires (UBA), Argentina
2 Departamento de Física, Facultad de Ciencias Exactas y Naturales, UBA, Argentina
3 Observatoire de Paris, LESIA, Meudon, France
4 Max-Planck-Institut für Sonnensystemforschung, Lindau, Germany
Departamento de Física
Juan José Giambiagi
International Living With a Star (ILWS), October 4-9, 2009,
Ubatuba, Brazil
An ICME is an expanding flux rope in the SW
How much can be affected its expansion by local environment conditions?
Outline
Expansion from analysis of different ICMEs at different solar distances D
Expansion from analysis of a MC at fixed D (non-dimensional rate along S/C path)
Comparison of expansion for different SW conditions:
-MC in a clean SW / Overtaken MC by fast SW
Anisotropy of expansion (axial and radial expansion)
International Living With a Star (ILWS), October 4-9, 2009, Ubatuba, Brazil
Evolution of ICMEs: key parameters from different events observed
at different solar distances D (good for global expansion)
[From Liu et al., Plan. & Space Sci. 2005]
S~D0.9, Np~D-2.3, T~D-0.3, B~D-1.4
Considering other studies (more events):
S~D0.8±0.1
[e.g., Bothmer & Schwenn ‘98; Leitner et al. JGR‘07]
Is the large dispersion due to the evolution in different ambients?
International Living With a Star (ILWS), October 4-9, 2009, Ubatuba, Brazil
NOT PERTURBED
Vx
Example of MC not perturbed,
(~ linear velocity profile for full MC)
Vc
t
Example of MC perturbed at the rear
(perturbed profile of the velocity)
PERTURBED
Dimensionless local expansion coefficient
[Demoulin et al., SolPhys, 2008;
Demoulin & Dasso, A&A, 2009;
Gulisano et al., A&A, in press 2009]
Globally: S=S0(D/D0)m
use dS/dt
can't use dS/dt
S=S0(D/D0)
Helios 1&2 MCs
For Not Perturbed
Vx ~ dS/dt = mVc S/D,
= D Vx /(t Vc2)
and S ~ t Vc
=> N ~ m
NoPerturbed ~ 0.9
For Perturbed
 = D Vx /(tVc2)
~ D Vx/(SVc)
Not Perturbed MCs present no correlation,
while Perturbed ones are correlated
=>  O ~ D0 m D1-m /(S0Vc) Vx
Black solid line corresponds to the expected global expansion S ~ Dm
Green line to an example of Not Perturbed MC
Blue dashed line to one possible example of Perturbed MC
International Living With a Star (ILWS), October 4-9, 2009, Ubatuba, Brazil
Radial and axial expansion:
different expansion rates?
Adapted from [Zurbuchen &
Richardson, Space Science Rev, 2006]
Radial expansion due
to solar wind pressure
decay
Back !!
Axial expansion due to
connectivity to the Sun
(self-similar: m=1)
International Living With a Star (ILWS), October 4-9, 2009, Ubatuba, Brazil
Modelling the magnetic flux rope
From in situ
observed B

possible to ‘orient’ the flux rope
& compare with models
e.g., MV
International Living With a Star (ILWS), October 4-9, 2009, Ubatuba, Brazil
We preliminary found a nearly isotropic expansion
cos()=zcloud•xGSE
Helios 1 & 2 MCs
International Living With a Star (ILWS), October 4-9, 2009, Ubatuba, Brazil
Summary and Conclusions
•Magnetic Clouds are expanding structures as consequence of the decrease of
the solar wind pressure (ambient) and connectivity to the Sun
•A non-dimensional local expansion rate (=VD/(tVc2)) can be defined and
determined from single point (1 S/C) in situ observations
•For no-overtaken MCs, the observed local expansion () was in
a full agreement with the global expansion (m~0.8±0.1)
•Local expansion can be significantly affected by flows that overtake MCs:
SW-cloud or cloud-cloud interactions [e.g. Dasso et al., JGR’09]
•Anisotropy in MC expansion rates is expected
(axial and radial expansion are due to very different physical mechanisms)
•However, we preliminary (work in progress) found that  is nearly isotropic
(statistically supporting connectivity to the Sun of MC legs for our sample)
Thank you very much for your attention !!!
International Living With a Star (ILWS), October 4-9, 2009, Ubatuba, Brazil
Additional Slides
Different MCs observed at different solar distances D
(good for global expansion)
np~D-2.8
S~D0.97
[From Kumar & Rust, JGR 1996]
Modeling evolution of MCs
from assuming:
(i) conservation of magnetic
fluxes and H
(ii) isotropic self-similar
expansion
S~D, np~D-3, B~D-2
Large uncertainties (only a few observed events)
B~D-1.8
Improvements
Better determination of exponents
(more events): S~D0.8±0.1
[e.g., Bothmer & Schwenn ‘98; Leitner et al. JGR‘07]
Moving boundary model [Demoulin & Dasso A&A‘09]:
For SW pressure decay as Psw(D)~D-np, global expansion
S ~ Dnp/4 ~ D0.7
[Demoulin talk SW12]
Solar Wind 12, June 21-June 26, 2009, Saint Malo, France
Learning from 1 S/C observations (fixed D) of one event (model and )
From Nakwacki et al. [COLAGE’07, Mexico]
V
t
Expansion from fitting model to Vx
t  tc
Vx  Vc  Vc
t T
[e.g., Farrugia et al., JGR’95;
Nakwacki et al., JASTP’08]
T≈ 3-3.3 days
<Vx,cloud>=-794km/s
tc: center V(tc)
V D
 
2
t Vc
[Demoulin talk SW12]
Radial expansion rate:
dR/dt  (0.03-0.045) AU/day
Non-dimensional expansion rate for local expansion
(no model is assumed)
[Demoulin et al., Sol Phys’08; Gulisano et al., poster SW12]
Solar Wind 12, June 21-June 26, 2009, Saint Malo, France
Based on observations:
S(D)~S0 (D/D0)m,
If dS/dt~V then ~m
Same event observed at 1AU and 5.4AU
ACE
[see more in Nakwacki et al., poster SW12]
SACE(D=1AU)=0.22AU
ACE=0.70
Ulysses
SUlysses(D=5.4AU)=0.63AU
Ulysses=0.65
Observations according with the expected increment of size:
Sexpected,Ulysses ~ SACE 5.4 ~ [0.62-0.72]AU
Solar Wind 12, June 21-June 26, 2009, Saint Malo, France
Pealing flux ropes via magnetic reconnection
y
x
Cumulative flux Fy/L
Fy ,cloud ( x)
L
.
  dx' By ,cloud ( x' )
By,cloud
Oct 20, 01:36UT
X in
From B=0 and invariance of B
along the main axis of the cloud
(valid to a general 2D-shape!):
 dx B
Xin
x
y ,cloud
Start:
Oct 18, 1995
at 18:58UT
Different end boundaries chosen by
previous authors [Lepping et al., JGR’97;
Larson et al., GRL’97; Janoo et al., JGR’98]
( x)  0
flux
rope
Oct 19, 07:26UT
Oct 19, 17:37UT
Cancelation of Fy,cloud
at a magnetic discontinuity
[from Dasso et al., A&A 2006]
Expansion of a partially pealed flux rope that is overtaken by SW
Back
The flux rope was partially
pealed from its front.
However, the ‘back’ still
~ as before reconnection,
showing ~ properties of a flux
rope and not of SW
OVERTAKEN
MC
Back!
=0.44±0.1 < 0.7
Adapted from [Zurbuchen &
Richardson, Space Science Rev, 2006]
Solar Wind 12, June 21-June 26, 2009,
Saint Malo, France
Example with reconnection in the MC front, but non-overtaken
~18hs
MC
Reconnected flux: ~ 20%-30% of total
[Dasso et al., Sol Phys, ‘07]
MC
size~0.26AU
This event: =0.7±0.1
Same as typical value for
no overtaken MCs without
reconnection [See Gulisano et al., poster
SW12; Demoulin talk SW12]
Thus, typical value of 
for no overtaken events,
even for reconnection conditions!
Cloud-cloud interaction
Two filament eruptions
MC1: MC ~ -15°, MC ~ 125°
~ 0.08 AU
H
MC2: MC ~ 55° & MC ~ 120°
~ 0.4 AU
[From Dasso et al., JGR 2009]
MC1: Typical coherent rotation of B (flux rope) but ...
Compressed  no typical expansion
(it is significantly pushed by MC2) no typical
linear profile of V and no typical low Tp and low 
MC2: huge MC, large impact parameter
Typical expansion factor (=0.7±0.1)
MC2 is almost not affected by MC1 (relative size)
Solar Wind 12, June 21-June 26, 2009, Saint Malo, France
Transients are ejected from the Sun toward the SW
•A subset of ICMEs can be observed as
‘Magnetic Clouds’ (MCs) in the SW
•Observed properties:
From [Zurbuchen & Richardson,
Space Science Rev, 2006]
- Low Tp
- Smooth and larger rotation of enhanced B
- Low proton plasma p
•Fast MCs driven a shock wave
(and a turbulent sheath of large n)
•Cold structures (low Tp)
Snow thrower
effect
•e-s flows along B (>100eVs): proxy
of magnetic connectivity
•Smooth and large coherent
rotation of B (helical structures),
increased respect to the SW
•Low plasma beta (p)  Fmag
Parker spiral B
Evolution of MCs in the heliosphere (more cases)
from Leitner et al. [JGR’07], in agreement with previous studies [Bothmer & Schwenn, AnnGeophys 1998]
Inner heliosphere
Tp~r- 1.2.±0.7
Inner heliosphere
np~r- 2.4±0.5
np~r- 2.6±0.1
Tp~r- 1.6±0.2
Inner heliosphere
D~r1.1.±0.4
D~r0.6±0.1
Inner heliosphere
B0~r- 1.6±0.4
B0~r-1.3±0.1
4th El Leoncito Solar Physics School, El Leoncito San Juan & La Punta San Luis, Argentina, Nov 24-29, 2008
Spacecraft
Observations
(MFI/Wind):
MC observed on
Oct 18-19, 1995
•Coherent Rotation of B
•Velocity profile flat (old cloud
without significant expansion)
•Shock wave in front (A)
•Magnetic hole (B): a signature of
reconnected field?
•Strong Alfvén waves activity
after the MC
From Lepping et al. [JGR, 1997]
Modelling the magnetic flux rope
From in situ
observed B

possible to ‘orient’ the flux rope
& compare with models
IAU Symposium 257 Universal Heliophysical Processes, Ioannina, Greece, Sep 15-19, 2008
[see more in Gulisano et al., poster SW12]
NOT OVERTAKEN
Expanding MC in a ‘clean’ SW
Observed by Helios 1 on Jan 7, 1975
OVERTAKEN
Expanding MC while fast SW is overtaken it
Observed by Helios 1 on Jun 23, 1980
Magnetic Reconnection: More ingredients than MHD are needed to evolution of B
Hall Effect:

B    [( U    B)  B]   2 B,
t
Ue
 ~ n 1 enlarged in IP
•From MHD eqs: U    B  U e , then B is frozen-in to the electron fluid
•Electrons travel faster in helical motion, thus B is accelerated respect to MHD
•Current sheet is tinnier and reconnection is more efficient
From numerical simulations of 2.5D incompressible HMHD [Morales et al., JGR’05]
2nd studied case: Nov 2004
From Harra et al. [Sol Phys 2007]
•We study this MC, which is in very
strong expansion
•Decreasing V
•Decreasing B
•There are different end boundaries,
according with different proxies (criteria)
Now, we consider expansion effects on flux cancellation
observed
z
B
y ,cloud
(t ) L(t )Vx ,cloud (t ) dt  0,
flux
rope
dx
x
modelled
No axial expansion
L(t ) D(t )

, with D(t )  Din  (t  tin )Vc
Lin
Din
V
L(t )
 1  (t  tin ) c
Lin
Din
with axial expansion
[Dasso et al, SolPhys
2007, in press]
Cloud
axis:
=-10°
=275°
Two
interacting
ICMEs
[From Dasso et al., JGR 2009]
Solar Wind 12, June 21-June 26, 2009, Saint Malo, France
MC overtaken by another MC
Two filament eruptions
ICME
MC1
MC2
H
Texp
MC2
MC1
[From Dasso et al., JGR 2009]
axial B
spacecraft path
across MCs
Solar Wind 12, June 21-June 26, 2009, Saint Malo, France
axial B
[From Dasso et al., JGR 2009]
Solar Wind 12, June 21-June 26, 2009, Saint Malo, France
Grad-Shafranov (Moestl)
•Two clouds,
•The first one: the satellite is crossing
•near the axis of the MC
•For the second it crosses far away,
• the impact parameters are large,
•The MVariance method is not adapted
•First event
• Ospan observations for the flare at 13:30
UT (12:48-14:00UT) Hebe
•C1.5 Xray flare (OSPAN)
•TRACE 195
•Second event
•M8.0 X ray flare (BBSO)
The events at the Sun
EIT 195 Å image on 13 May
at 11:42 UT.
Magnetic linear force free
model of AR 10759 before
the M 8.0 flare
= -1.6 10-2 Mm-1
Negative magnetic helicity in
the AR field and surroundings
TRACE 195 Å image on 14 May at 12:45 UT. Two
post-flare arcades are visible.
•Negative helicity on the Sun and in the MCs
Open and closed fields in magnetic clouds
Suprathermal (320 eV) electron pitch angle distributions for 8 Nov 04
open
closed
Shodhan et al. [2000]
magnetic cloud
• Counterstreaming
suprathermal electrons
indicate field lines
connected to the Sun at both
ends (closed)
• On average, clouds are
nearly half open
Opening ICMEs by Interchange Reconnection
Gosling, Birn, and Hesse [1995]
• At CME liftoff
– a. Partial disconnection (closed-closed) creates flux
rope coil
Crooker, Gosling, and Kahler [2002]
– b. Interchange reconnection (closed-open)
opens coil
• As ICME moves out into
heliosphere
– Interchange reconnection at Sun
may continue to open field lines