Transcript PowerPoint Presentation - The Center for Astrophysical

The Center for Astrophysical Thermonuclear Flashes
Overview of the Flash Center
Don Lamb
Annual Site Review
October 28-29, 2004
(http://flash.uchicago.edu)
An Advanced Simulation and Computation (ASC)
Academic Strategic Alliances Program (ASAP) Center
at The University of Chicago
The Ultimate Goal:
Understanding Astrophysical Flashes
X-ray burst: GS 1826-24
Type Ia SN: SN 1994D
Picture credits: NASA
Cosmic nucleosynthesis: how is the stuff we’re made of
produced?
Guideposts to the universe: using exploding stars as “rulers”
for the universe
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Nova Cygni 1992
Our “Overarching Goals”
To build a new generation code for computing
astrophysical thermonuclear flashes involving
compact stars
 Incorporate advances from CS, applied math, physics
 Verify and validate code and its components
To produce great science
Astrophysics and physics
Computational sciences [CS, Applied math, Math]
Training/education
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Code Highlights During Past Year
 Updated Code Project Plan
 Primary objectives for FY04 are to
 Release Flash 2.4 – Done
 Support addition of modules to Flash 2 required for astro
simulations of Type Ia SNe – Done
 Develop and implement Flash 3 Framework – Done
 Implement a basic set of units in Flash 3 – Done
 Run first application of Flash 3 (“end-to-end” test) – Done
 Identified and helped to solve a series of problems
w. ASC platforms (e.g., ALC and QSC)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
More Flash Code Highlights
 Organized and hosted Flash Tutorial
 Researched, selected, purchased, and installed
“ellipse” Linux cluster:
 Sought and received invaluable advice from CS group
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at ANL
Cluster has 16 nodes (32 processors)
Includes 13 Tbyte RAID system
Processors and graphics cards selected are identical or
similar to those used at ANL
Cluster will be used primarily for code development and
visualization
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Code Future Objectives
 Primary objectives for FY05 are to
 Implement remaining units in Flash 3
 Create Flash 3 Developer’s Guide
 Explore open design issues (I/O, gravity, particles)
 Interact successfully w.
 Astro group to support, document, maintain, and
bug-track code; and to solve platform problems
 Comp Phys group to ensure framework support
for new algorithms
 Visualization group to bring Flashview into
Flash 2 and 3
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash CS and Visualization Highlights
During Past Year
 Flash selected as Marquee application for LLNL
BlueGene/L
 Flash 3 is now running as “benchmark application”
on Blue Gene/L
 Flash 3 is driving developments in CS and Viz
 Steadily increasing importance of visualization for
astrophysics simulations has led to creation of
Visualization group w. Mike Papka as leader
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Validation Highlight: 3-D Simulations
of Shock-Cylinder Experiment
 Basic morphology of our 2-D simulations agrees
with experimental data and simulations of others,
but details differ across all groups
 With Todd Dupont (basic physics group), we
have done extensive study to determine initial
conditions consistent with experimental data
 We have developed quantitative, relevant,
practical metrics
 Our 3-D simulations demonstrate that flow field
is fully 3-D in nature
 Experimenters are planning to make measurements in vertical plane, prompted by our
simulations
Weirs et al. (2004)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Comp Phys and Validation
Future Objectives
Primary objectives during FY05 are to:
 Continue development and testing of low-Mach
number, implicit hydro solver
 Continue development and testing of level-set
flame-tracking module
 Improve flame module, taking into account results
of “Astrophysical Flame Laboratory” simulations
 Continue effort to build local radiation transfer
capability for Type Ia SN light curves and spectra
 Publish results of validation studies of LANL shock
cylinder experiments
 Initiate further validation studies w. LANL and LLNL
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Astrophysics Highlights
During Past Year
 Updated Astrophysics project plan
 Continued work on novae (Plewa, Rubini, Pan,
Truran)
 Won INCITE award of 2.7 million cpu-hours on
Seaborg for Flash simulations of Type Ia SNe
 Carried out studies of sub-grid flame model using
“Computational Astrophysical Flame Laboratory”
(Messer)
 Carried out whole-star simulations of Type Ia SN
deflagration phase (Calder)
 Octant models of central ignition
 Whole-Star models of central ignition
 Whole-Star models of off-center ignition
 Discovered possible new Type Ia SN mechanism
(Plewa)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Discovery of New Type Ia SN Mechanism
 Whole-star 3-D simulations show that slightly off-center
ignition creates hot bubble of material that rises rapidly
to surface of white dwarf
 As bubble breaks through surface, hot material flows
across surface of star at high velocity, pushing material
in surface layers of star ahead of it
 Flow converges at opposite point on surface of star;
resulting compression raises temperature and density
of surface material, initiating detonation
 First model of Type Ia SN in which detonation occurs
“naturally” (i.e., without being put in by hand)
 Star pre-expands while hot bubble material is flowing
across surface of star, so that when detonation occurs,
density of star has decreased enough that both nickel
and intermediate mass elements are produced
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Answers to Key Questions Re Type Ia SNe
In Gravitationally Confined Detonation Model
 How does insensitivity to initial conditions happen?
—off-center ignition accommodates some variations in initial
conditions, but more study definitely needed
 What produces the range of Ni masses that are observed in
Type Ia SNe that may be the origin of the Phillips relation?
—variation in initial conditions of off-center ignition produces
range in masses of hot bubble, range in amounts of preexpansion, and therefore range in amounts of Ni, but more
study definitely needed
 How does a detonation occur in a medium that has no walls
(i.e., that is gravitationally confined)?
—gravitationally confined detonation (colliding shocks in focused
flow of hot material across white dwarf surface), but more study
definitely needed
 Why do 1-D models do better than 2-D models and much better
than 3-D models?
—bubble burns only a few percent of MWD,producing a preexpanded star that is nearly spherically symmetric when
detonation occurs; i.e., mimics 1-D model!
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Criteria for Success
 “Achieving scientific leadership in the chosen application
discipline:”
 Have achieved scientific leadership in nova problem
 Are now a “player” in Type Ia supernova problem
 “Demonstration of scientific breakthroughs and/or
solutions to important problems through advanced
computational science:”
 Demonstrated viable solution to previously unsolved problem of
pre-nova mixing
 Discovered promising new Type Ia supernova mechanism
(“Gravitationally Confined Detonation”)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center-Wide Team Effort
on Type Ia SN Problem
 Pre-2003 – Flash Code developed
 Pre-2003-present – Flash Code maintained
 2003 – Flame capturing module developed and
implemented
 2003-present – Flash Code migrated to new ASC
platforms (QSC, ALC, BlueGene/L,…) and problems
solved
 2003 – 3-D entire star slightly off-center simulations
done
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Off-Center Entire Star Simulation
of Deflagration Phase of Type Ia SNe
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center-Wide Team Effort
on Type Ia SN Problem
 Pre-2003 – Flash Code developed
 Pre-2003-present – Flash Code maintained
 2003 – Flame capturing module developed and
implemented
 2003-present – Flash Code migrated to new ASC
platforms (QSC, ALC, BlueGene/L,…) and problems
solved
 2003 – 3-D entire star slightly off-center simulations
done
 2003-2004 – Multi-pole gravity developed and
implemented
 2003-2004 – Multi-grid gravity speeded up
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center-Wide Team Effort
on Type Ia SN Problem
 2004 – Tracer particles developed and implemented to
determine nucleosynthetic yields
 2004 – Distributed nuclear burning network being developed
in order to follow detonation phase
 2004 – Data transfer rate from ASC platforms improved
 2004 – Cluster purchased, installed, and operating system
problems solved
 2003-present – Flashview and visualization of Type Ia SN
deflagration phase simulations done (e.g., movies)
 2004 – Type Ia SN post-deflagration phase 2-D simulations
done
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
2-D Simulation of Post-Deflagration
Phase of Type Ia SNe
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center-Wide Team Effort
on Type Ia SN Problem
 2004 – Tracer particles developed and implemented to
determine nucleosynthetic yields
 2004 – Distributed nuclear burning network being developed
in order to follow detonation phase
 2004 – Data transfer rate from ASC platforms improved
 2004 – Cluster purchased, installed, and operating system
problems solved
 2003-present – Flashview and visualization of Type Ia SN
deflagration phase simulations done (e.g., movies)
 2004 – Type Ia SN post-deflagration phase 2-D simulations
done
 2004 – Discovery of possible new Type Ia SN mechanism
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center-Wide Team Effort
on Type Ia SN Problem
 2003-present – Boussinesq reactive flow simulations done,
leading to new insights
 2003-present – “Computational Astrophysical Flame
Laboratory” simulations done, leading to new insights and
improved sub-grid flame model
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Self-Regulating Turbulent Flame
Steady-state turbulent flame speed does not depend on small-scale physics:
Sl=1.07 x 106 cm/s
Sl=2.14 x 106 cm/s
St  Sl 
 = 2.84 x 1013 cm2
St   gLA
 = 1.41 x 1013 cm2
Messer et al. (2004)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center-Wide Team Effort
on Type Ia SN Problem
 2003-present – Boussinesq reactive flow simulations done,
leading to new insights
 2003-present – “Computational Astrophysical Flame
Laboratory” simulations done, leading to new insights and
improved sub-grid flame model
 2004 – New diagnostics developed for “Computational
Astrophysical Flame Laboratory”
 2004 – First Monte Carlo radiation transfer code calculations
of spectra for Flash Type Ia SN hydro simulations
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
First Contact Between Flash Hydro
Simulations of Type Ia SNe and Observation
Kasen and Plewa (2004)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center-Wide Team Effort
on Type Ia SN Problem
 2003-present – Boussinesq reactive flow simulations done,
leading to new insights
 2003-present – “Computational Astrophysical Flame
Laboratory” simulations done, leading to new insights and
improved sub-grid flame model
 2004 – New diagnostics developed for “Computational
Astrophysical Flame Laboratory”
 2004 – First Monte Carlo radiation transfer code calculations
of spectra for Flash Type Ia SN hydro simulations
 2004-present – Development and testing of low-Mach
number hydro solver (will allow us to investigate “smoldering
phase”)
 2004-present – Development of level-set interface capturing
module
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Future Flash Astrophysics Objectives
Primary scientific objectives during FY05 will be to
carry out large-scale, integrated, multi-physics
simulations of Type Ia SNe
 Focus on deflagration phase
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Carry out verification studies
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Resolution studies of center and off-center ignition
Carry out studies of sensitivity to initial conditions
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Parameter study of initial offset distances and
velocities
Study effect of turbulence
 Carry out 2-D simulations of detonation phase
 Study nucleosynthetic yield, using tracer
particles
 Construct spectra for some Flash models
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Program of Enrico Fermi Institute
Mini-Symposium on Type Ia SNe
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Reference Frame Column
in Physics Today by Leo Kadanoff
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Visibility of Flash Center
in Scientific Community and Beyond
 2004-present – Award of INCITE time (2.7M cpu-hours) on
Seaborg and selection of Flash code as Marquee application on
BlueGene/L
 Article on “Coming Crisis in Large-Scale Simulations” featuring
Flash Center results will appear in a future Physics Today (Doug
Post)
 Educational and public outreach
 Major upgrade of Flash Center website (incl. menu of Flash movies)
 Showing of Flash Center movies at Adler Planetarium “Short Course”
for planetarium staff and directors and disseminated to many
planetaria
 Development of 3-D movies of wind-wave mixing in novae and
deflagration phase (“jellyfish”) of Type Ia SNe
 Creation of exhibit of Flash Center results and movies for Sci-Tech,
Hands-On Science Museum in Aurora, IL
 Invitation to provide multi-projector Flash Center movies for
exhibition at Smithsonian Air and Space Museum in Washington, DC,
and for dissemination to planetaria throughout U.S.
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Visibility of Flash Center in Scientific
Community – Refereed Papers
 On Variations in the Peak Luminosity of Type Ia Supernovae (Timmes, Brown,
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and Truran, ApJ, 590, 83, 2003)
Response of Model and Astrophysical Flames to Curvature and Stretch (Dursi,
et al., ApJ, 595, 955, 2003)
Linear Instability of Astrophysical Flames in Magnetic Fields (Dursi, ApJ, 606,
1039, 2004)
Morphology of Rising Hydrodynamic and magneto-Hydrodynamic Bubbles from
Numerical Simulations (Robinson, et al. ApJ, 601, 621, 2004)
On Heavy Element Enrichment in Classical Novae (Alexakis, et al., ApJ, 602,
931, 2004)
A Comparison of High-Resolution 3D Numerical Simulations of Turbulent
Rayleigh-Taylor Instability: Alpha-Group Collabpration (Dimonte, et al., Phys.
Fluids, 16, 1668, 2004)
Validating Astrophysical Simulation Codes (Calder, et al. CiSE 6, 10, 2004)
On the Nonlinear Evolution of Wind-Driven Gravity Waves (Alexakis, et al.
Phys. Fluids, 16, 3256, 2004)
Type Ia Supernova Explosion: Gravitationally Confined Detonation (Plewa,
Calder, and Lamb, ApJ, 612, L37, 2004)
Laboratory Astrophysics Experiments for Simulation Code Validation: A Case
Study (Calder, Ap&SS, in press, 2004)
Type Ia Supernovae: Simulations and Nucleosynthesis (Brown, et al. Nuclear
Physics A, in press, 2004)
Type Ia Supernovae: An Asymmetric Deflagration Model (Calder et al., ApJ,
submitted, 2004)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Visibility of Flash Center
in Scientific Community – Talks
 2 invited talks at APS/DPP in Albuquerque in October 2003 (Dwarkadas,
Rosner)
 3 invited talks at Chicago Workshop on Type Ia SNe in November 2003
(Khoklov, Calder, Brown)
 Talk at LES Workshop at Caltech in December 2003 (Plewa)
 2 oral talks at 192nd AAS Meeting in Atlanta, GA, in January 2004
(Alexakis, Calder)
 4 invited talks at 5th HEDLA Meeting in Tucson, AZ, in March 2004
(Rosner, Khokhlov, Calder, Lamb)
 3 invited talks at Ringberg Workshop on Nuclear Astrophysics in March
2004 (Calder, Brown, Truran)
 Invited talk at Workshop on Combustion and Type Ia SNe in Sedona, AZ,
in May 2004 (Plewa)
 2 talks at ASC Alliance/Laboratory Verification and Validation Workshop,
La Jolla, CA, in July 2004 (Weirs, Plewa)
 Talk at 9th International Workshop on Physics of Compressible Turbulent
Mixing, Cambridge, UK, in July 2004 (Weirs)
 3 invited talks at Conference on AMR Simulations in Cosmology, Durham,
UK, in June 2004 (Dubey, Gallagher, Sheeler)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Visibility of Flash Center
in Scientific Community – Talks (Cont.)
 2 invited talks at INT Workshop on Supernova Theory and
Nucleosynthesis in Seattle in July 2004 (Lamb, Truran)
 4 invited talks at INT Workshop on Type Ia SNe in Seattle in August 2004
(Bronson, Calder, Lamb, Truran)
 Astronomy Department seminar at Notre Dame in September 2004
(Calder)
 Astronomy Department colloquium at Illinois in September 2004 (Plewa)
 Physics Department seminar at Illinois in September 2004 (Plewa)
 Astronomy Department colloquium at Maryland in September 2004
(Plewa)
 Astronomy Department colloquium at Vanderbilt in November 2004
(Calder)
 Astrophysics seminar at Fermilab in Winter 2005 (Plewa)
 Invited talk and contributed talk at Texas Symposium on Relativistic
Astrophysics in Palo Alto, CA, December 2004 (Khokhlov, Messer)
 4 contributed talks at AAS meeting in San Diego, CA, January 2005
(Brown, Messer, Truran, Zhang)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center Visitor Program
 Marko Arienti (Caltech) visited for two weeks in February; he
worked w. Alexei Khoklov on simulations of detonations in solids
 Dave Dearborn (LLNL) visited in April; he gave a Flash Center
colloquium on Earth-crossing asteroids
 Peter Hoeflich (U. Texas at Austin) visited for two weeks in April
and again in September; he worked w. Alexei Khokhlov to port
radiation transport modules to Chicago for eventual use in
simulating Type Ia SNe light curves and spectra, and participated
in the EFI Mini-Symposium on Type Ia SNe
 Snejana Abarzhi (Stanford Turbulence Center) visited in early
May; she gave a talk on the Rayleigh-Taylor instability
 Wolfgang Hillebrandt (Max Planck Institute fur Astrophysik),
who is on the Flash Center External Advisory Committee, visited
in early May; he gave a Cosmology Seminar on Type Ia SNe
 Luigi Iapichino (Max Planck Institute fur Astrophysik), visited for
a week in May; he worked w. people on the smoldering phase of
Type Ia SNe
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center Visitor Program (Cont.)
 Inma Dominquez (U. Granada, Spain) is visiting for a month;
she is learning to use the Flash Code and is working w. members
of the Center on models of the progenitors of Type Ia SNe
 Paul Woodward (U. Minnesota) visited in late May; he is
interested in contributing his interface tracking algorithm to Flash;
his group has great experience w. flow diagnostics from which we
can learn a great deal; visit was very productive for both sides
 Francesco Rubini (Italy) visited for six months and will return
early next year to continue working on the smoldering (preoutburst) phase of novae
 Dan Kasen (Johns Hopkins) visited for one month this summer;
he will be worked w. Tomek Plewa to do first radiation transfer
calculations of spectra for new Type Ia SN mechanism
 Marco Comparato (Italy) will visit in November and December
 Yingjie Liu (Georgia Tech) will visit in August 2005 to work on
level set methods for interface tracking
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center Folks Are Joining the Labs
 Lori Freitag (cs group)
permanent staff member, LLNL
 Scott Wunch (basic phys group) research fellow, SNL
(Livermore)
 Alex Heger (astro group)
research fellow, T Division, LANL
 Andrew Siegel (code group)
permanent staff member, MCS
Division, ANL
 Katherine Riley (code group)
staff member MCS Division,
ANL
 Frank Timmes (astro group)
National Security Fellow and
T-6 Group Leader, LANL
 Andrei Draganescu (basic phys group)
staff member,
SNL (Albuquerque)
 Greg Weirs (comp phys & validation group)
staff member,
SNL (Albuquerque)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Flash Center Folks Are Going To
Top-Notch Positions
 Ed Brown (astro group)
Assistant Professor, Department
of Physics and Astronomy, Michigan State University
 Jonathan Dursi (astro group)
Postdoctoral Fellow, CITA,
Toronto, Canada
 Andrea Mignone (astro group)
postdoc in Torino, Italy
 Alexandros Alexakis (astro group)
postdoc in NCAR
Advanced Study Program
 Annie Sandman (solar MHD)
did senior thesis w.
Flash Center and graduated spring 2004, is now graduate
student at Rice University
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Recruitment in Past Year
 New senior faculty member in A&A who is actively working
on Type Ia SN problem (Alexei Khokhlov)
 Visiting senior faculty member in math (Henri Berestycki)
 Two new postdoctoral research associates in astro
group from pool of ~ 40 applicants (Alexei Poludnenko and Ju
Zhang)
 Two new postdoctoral research associates in comp
phys and V&V group from pool of ~ 80 applicants (Dahai Yu)
 Three new staff members in code group (Katie Antypas,
Jignesh Joshi, Noel Taylor)
 New system administrator (Shawn Needham)
 Two new graduate students to work w. Flash (first-year
students Justin Johnsen in A&A and Andriy Zhyglo in Physics
 Undergraduate student to work w. Flash (Jason Sherwin)
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Education
 CS and computational science courses being taught:
 A&A, CS and Math Department courses (scientific computation,
numerical hydro, CFD, computational astrophysics, visualization)
 CS Master’s Program courses (intro. to programming, parallel
programming, adv. software engineering, Java, adv. Java)
 CS Master’s Program has been a vital source for recruiting code
group members (Gallagher, Needham, Sheeler)
 Computer Science Department degree program in
computational mathematics is in its first year and growing:
 Program involves courses in CS, Math, and other sciences
 Flash Center expects to support 2 students in this program in
2005-2006
 PhD degrees awarded and expected:
 Alexakis, Draganescu, Dursi, and Mignone graduated in 2004
 Winn expected to graduate in June 2005
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Vision for Future of Flash Center
Beyond the Next Three Years
Flash Center Type Ia SN hydro
and radiation transfer simulations
Supernova Acceleration Probe
(SNAP) scheduled for 2013-2020
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Type Ia SNe – An Overarching Theme of
Flash Center
 1997 – Flash Center proposed and funded
 1998 – Observations of Type Ia SNe led to discovery that rate of
expansion of universe is accelerating
 1997-present – Flash Code developed
 2003 – Flash Center begins work on Type Ia SNe
 2003 – DOE and NASA commit to Joint Dark Energy Mission (SNAP)
 2004 – Flash Center discovers new Type Ia SN mechanism
 2004 – First Flash Center spectra of Type Ia SNe
 2005-2013 – Flash Center will be able to contribute to design of SNAP
instruments and to scientific observing strategy
 2013-2020 – SNAP mission
 2013-2020 – Flash Center will be able to contribute to
 understanding Type Ia SNe through comparison of simulations and
observations
 minimizing systematic errors that will limit accuracy with which properties
of Dark Energy can be determined
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Specifics of Flash Center
Beyond the Next Three Years
 Code and CS
 Core support from University of Chicago
 Major additional support from ANL (CS and Viz)
 Flash code continues to be a benchmark application for world’s
fastest computers and driver for advances in CS and Viz
 Comp Phys and Validation
 Seek support through collaborations with NNSA labs to do
validation experiments (e.g., at NIF)
 Strong effort this year to renew collaboration w. Bruce
Remington and others at LLNL
 New postdoctoral research associate has been hired to
increase activity in this area
 Astrophysics
 Create “Type Ia SN center” at University of Chicago
 Support and participate in SNAP mission (e.g., in studies of
dark energyTheand
cosmology)
ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Responses to 2003 Review Team Report
Recommendation
Action
Strategic Direction:
 Develop 5-year plan for integrated simulations w. milestones
 Maintain strategic focus on Type Ia SN problem
 Prioritize implicit solvers, transport, and validation
Done
Done
Done
Flash as a Community Code:
 Develop and release explicit design documentation for Flash 3.0
Done
 Create a Developer’s Guide
Underway
 Ensure that new physics packages and code modules
are easily implemented
Done
 Visualization should be a routine feature available
to Flash users
Underway
 Flash Center should host annual workshops or conferences
for Flash user/developer community
Done
 Flash design and implementation plan needs to accommodate
production usage of Flash as well as continuous development
Done
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
More Responses to 2003 Review Team Report
Recommendation
Action
Verification and Validation:
 Rigorously pursue Verification
 Establish a V&V methodology that is an integral part
of the astrophysics research and Flash development
Underway
Underway
General:
 Keep effort to develop Flash 3.0 going
 Take advantage of existing numerical methods
and techniques wherever possible
 Enhance mentoring of staff and students
 Improve internal mechanisms for collaboration
and communication, esp. wrt. graduate students
 Strengthen visitor program
 Increase recruitment of graduate students
 Develop “curriculum” for Flash graduate students,
including formal courses as well as training and seminars
 More and improved office space for staff and post docs
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
Done
Done
Underway
Underway
Done
Underway
Underway
Underway
Issues and Challenges
 Code group needs increased manpower and resources to
 Maintain Flash code
 Support large-scale astro simulations
 Make deep changes to Flash code & research challenging code issues
 Comp phys group needs increased manpower and
resources to
 Support new astro simulations
 Simulate experiments at NNSA labs – an activity vital to future of Flash
Center beyond the next three years
 Astrophysics group needs increased manpower and
resources to exploit ability Flash code now has to address key
astrophysics problems
 Major funding issue: Alliance Centers funding uncertain at a time
when we need to
 Support diversified code effort
 Expand validation effort
 Exploit Flash code for key astrophysics problems
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
ASC Platform Usage
Monthly Usage
Frost
ALC
Cumulative Usage
QSC
Seaborg
Frost
900
ALC
QSC
Seaborg
25
800
20
CPU hours in 100000
600
500
400
300
15
10
5
200
100
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
A
ug
n
Ju
A
pr
b
Fe
D
ct
O
A
ug
n
Ju
A
pr
b
Fe
ec
D
ct
ec
0
0
O
CPU hours in 1000
700
Issues and Challenges
 Access to computational resources is a major issue:
 As was already true at the time of the 2003 site review, we can use every cycle




we can lay our hands on to do highly significant astrophysical simulations (i.e.,
we are now “cycle-bound” in the science that we are able to do).
We have aggressively sought to exploit ASC platforms to the full and have
sought access to non-ASC platforms (e.g., INCITE proposal to use Seaborg).
We are aggressively seeking access to new ASC platforms (e.g., Blue Gene/L),
but these machines will not come on line for a year or more.
ALC was designated as the main platform for Alliance centers in November
2003; however, it is an experimental machine. Close collaboration w. the
ASAP CRT and w. consultants at LLNL Computing have been instrumental in
our beginning to use ALC, but no production run has been successfully carried
out to date. Recent progress encourages us to believe that we will be able to
make full use of ALC in the near future.
The problems w. the ASC platforms temporarily placed a large burden on the
code group, delaying the start of work on Flash 3 until February 2004.
 This year we had a harder time exploiting ASC computational
resources. We are therefore appreciative that Frost will continue
to be available to the Alliance centers, and are working with LLNL
Computing to achieve reliability on ALC for Flash runs.
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago
… which brings us to
Questions and Discusson
The ASC/Alliances Center for Astrophysical Thermonuclear Flashes
The University of Chicago