Download Document

QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Discovering the Complexity of
Supernovae through 3D
Simulations
John M. Blondin
NC State University
AAS/AAPT
January 9, 2007
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
We begin our story in 1572…
``On the 11th day of November in the evening after
sunset, I was contemplating the stars in a clear sky.
I noticed that a new and unusual star, surpassing the
other stars in brilliancy, was shining almost directly
above my head.’’
-- Tycho Brahe
AAS/AAPT
January 9, 2007
Again in 1604…
Johannes Kepler observed a “stella nova” that became as
bright as Jupiter, but faded away after a couple months.
AAS/AAPT
January 9, 2007
For 400 years there has not
been a supernova in our Galaxy
… we are still waiting!
But, in a nearby galaxy not
long ago (February 1987)…
AAS/AAPT
January 9, 2007
We can learn even more by looking at what
is left hundreds of years later.
AAS/AAPT
January 9, 2007
Remnants of Supernova Explosions
Relic Blastwave
AAS/AAPT
Spinning Neutron Star
January 9, 2007
The iron core contains about 3 times
the mass of our Sun, but it is roughly
the size of our Earth.
This iron core collapses under its own
weight until it is small enough to fit
inside Puget Sound.
At this point the core is as dense as
the nucleus of an atom and it cannot
compress any further. The rest of the
star ‘bounces’ off this hard core and
explodes off into space???
AAS/AAPT
January 9, 2007
It all starts with core collapse…
AAS/AAPT
January 9, 2007
The Supernova story has a long
history of computational physics…
• 1966 Colgate and White
Neutrino-Driven prompt explosion
• 1985 Bethe and Wilson
Shock reheating via neutrino energy deposition
• 1992 Herant, Benz, and Colgate
Convective instability above neutrino-sphere
AAS/AAPT
January 9, 2007
The last decade has seen a great
deal of interest in multidimensional
effects:
Convection with the protoneutron star
Neutrino-driven convection
below the stalled shock
Instability of the stalled shock
All of these may operate
together!
AAS/AAPT
January 9, 2007
First generation of 2D SN models hinted at
a low-order asymmetry in the shock wave
at late times (100’s of msec after bounce).
Burrows, Hayes & Fryxell 1995
AAS/AAPT
January 9, 2007
REU Students, Summer 2000
Christine DeMarino
Brett Unks
Dana Paquin
AAS/AAPT
January 9, 2007
To investigate the dynamics of the stalled supernova shock,
we consider an idealized problem:
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
In One Dimension:
Analytical: Houck & Chevalier (1992) presented a
linear stability analysis.
Numerical: Blondin et al. (2003) perturb SAS and
watch the evolution.
Radius
Pressure Perturbation
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Time ->
AAS/AAPT
January 9, 2007
SN Code Verification
Houck and Chevalier 1992
Blondin and Mezzacappa 2005
This post-bounce model provides an opportunity to verify supernova
codes against the results of a linear perturbation analysis.
AAS/AAPT
January 9, 2007
Spherical Accretion Shock Instability
Blondin, Mezzacappa, DeMarino 2003, ApJ, 584, 971
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
The SASI is a global acoustic mode:
The spherical accretion shock acts as an acoustic cavity,
with a trapped standing wave growing exponentially with time.
AAS/AAPT
January 9, 2007
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
Must move to 3D!
This initial SASI discovery with
axisymmetric 2D simulations
pointed to the obvious need for
models in full 3D.
AAS/AAPT
January 9, 2007
Hurdles for Large-Scale 3D
Simulation code
Not a problem
Floating points
Thank you DOE
Data output
It works
Data transport
Does not work
Visualization and analysis
I can’t see!
AAS/AAPT
January 9, 2007
First Results: SASI Exists in 3D
• 3D Cartesian grid
• 100 Million zones
• 100’s of processors
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
• 100’s of GB in full run
Without interactive access to the data, this was science in the dark!
AAS/AAPT
January 9, 2007
Science Begins with Data
Scientific discovery is done with interactive access to data.
•
•
•
Must have interactive access on a
large-memory computer for
analysis and visualization.
Must have high bandwidth in
accessing the data.
Must have sufficient storage to
hold data for weeks/months.
AAS/AAPT
Shared
file
system
Cray
X1
Billion-cell
simulation
in 30 hours
generates
4 terabytes
Visualization
platform
January 9, 2007
Interactive Visualization of TB Datasets
QuickT ime ™an d a
TIFF ( Uncomp res sed) deco mpre ssor
ar e need ed to see this pictur e.
A commodity linux cluster
provides all the ‘must haves.’
Data is sliced into slabs and
stored on local disks on the
cluster nodes.
EnSight Gold provides an easy
visualization solution, including
remote client-server operation
and collaboration.
AAS/AAPT
January 9, 2007
QuickTime™ and a
Animation decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
QuickTime™ and a
Video decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
QuickTime™ and a
Video decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
QuickTime™ and a
Video decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
AAS/AAPT
January 9, 2007
QuickTime™ and a
Video decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
AAS/AAPT
January 9, 2007
AAS/AAPT
January 9, 2007
AAS/AAPT
January 9, 2007
QuickTime™ and a
Microsoft Video 1 decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
SASI
A non-rotating, spherically symmetric progenitor star can leave
behind a neutron star spinning with a period of tens of milliseconds.
AAS/AAPT
January 9, 2007
A Million Second Chandra View of Cassiopeia A
Hwang et. al. 2004
“These are most likely due to
jets of ejecta as opposed to
cavities in the circumstellar
medium, since we can reject
simple models for the latter.”
AAS/AAPT
January 9, 2007
If the progenitor star
possessed an
asymmetric stellar wind
(e.g., due to rotation),
the supernova remnant
driven into this relic
wind would reflect the
asymmetry of the wind.
In this 2D simulation,
the density in the
progenitor wind is four
times denser in the
equatorial plane than at
the poles.
AAS/AAPT
Forward shock
Reverse shock
January 9, 2007
QuickTime™ and a
Video decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
Never believe a jet in 2D…
equator
pole
q
equator
AAS/AAPT
radius
January 9, 2007
QuickTime™ and a
Video decompressor
are needed to see this picture.
AAS/AAPT
January 9, 2007
A “Jet” from a
Spherical Supernova
Shocked
Ejecta
Fast
Ejecta
Leading
Shockwave
AAS/AAPT
January 9, 2007