CRPC researchers are involved in ASCI projects that range from exploration of exploding stars and the size of the universe to simulation of advanced rockets and materials. They are working on Level 1 projects at the California Institute of Technology (Caltech), the University of Chicago, and the University of Illinois. Other institutions receiving Level 1 grants were Stanford University and the University of Utah. In addition, teams at Rice University and Los Alamos National Laboratory (LANL) are involved in projects that support ASCI research in many areas.

Center for Astrophysical Thermonuclear Flashes

Argonne National Laboratory (ANL) CRPC researchers are collaborating with the University of Chicago Center for Astrophysical Thermonuclear Flashes to study the physics of exploding stars and the nuclear detonations that occur when matter in space is crushed by gravity onto the surfaces of extremely dense stars. Exploding stars, or supernovae, emit 10 billion times more power than the sun and shine as brightly as an entire galaxy of stars. Learning more about supernovae will help answer important questions about the universe, including its true size.

"Supernovae are enormously bright, so they can be seen at great distances. And because most of them seem to shine with equal intensity, we have tried to use them to measure the distance to remote galaxies" explains Flash Center Director Robert Rosner, a professor of astrophysics at the University of Chicago. "If you read in the papers that the size of the universe just increased or decreased, it's probably because the estimate of the brightness of supernovae changed. To understand the true size of the universe, we need to determine whether these incredibly bright objects can be relied on as the universe's 'standard candles.' This project will allow us to do that."

Supernovae play another key role--that of producing the universe's heavy elements. Elements up to the density of iron are produced many millions of years before the stars explode, while the heaviest elements, like gold, platinum, and uranium, are created during the explosion.

Virtually every aspect of this study represents a computational Grand Challenge problem, so large-scale numerical simulations are at the heart of its resolution. The computational challenges and needs include development of new scalable algorithms, structuring of large complex physics codes, domain decomposition, load balancing, parallel adaptive mesh refinement, performance diagnostics, debugging tools, parallel I/O, and visualization of the highly complex three-dimensional results.

The collaboration between ANL and the University of Chicago builds on an existing joint program in computational science that makes use of an ultra-high-speed, 155 megabit-per-second computer network; a data storage system that stores and accesses 35 trillion bytes of data; and virtual reality equipment that will create three-dimensional, virtual-reality projections of the cosmic explosions. Led by CRPC researcher Rusty Lusk, the Flash Center Computer Science Group at ANL is investigating and developing computer science infrastructure elements. These include tools for performance monitoring, characterization, optimization, and distributed and parallel computing; standards for common component architecture; diagnostics for high-performance data transmission and storage; and high-performance visualization of large data sets.

For more information, see www.flash.uchicago.edu/research/org.html

Center for Simulation of Dynamic Response of Materials

Led by Principal Investigator Daniel Merion and Executive Director James Pool, both CRPC researchers at Caltech, the Center for Simulation of Dynamic Response of Materials is constructing a virtual shock physics facility in which the full three-dimensional response to a variety of target materials can be computed. This involves a wide range of compressive-, tensional-, and shear-loadings, including those loadings produced by detonation and energetic materials.

The goals of this project are to:

1. facilitate computation of a variety of experiments in which strong shock and detonation waves are made to impinge on targets consisting of various combinations of materials,

2. compute the subsequent dynamic response of the target materials, and

3. validate these computations against experimental data.

The research centers on three primary stages required to conduct a virtual experiment in the facility-detonation of high explosives, interaction of shock waves with materials, and shock-induced compressible turbulence and mixing. The modeling requirements are addressed through five integrated research initiatives that guide the key disciplinary activities:

• Modeling and simulation of fundamental processes in detonation
• Modeling dynamic response of solids
• First-principles computation of materials properties
• Compressible turbulence and mixing
• Computational and computer science infrastructure

For more information, see www.cacr.caltech.edu/ASAP/

Center for Simulation of Advanced Rockets

Based at the University of Illinois at Urbana Champaign, the Center for Simulation of Advanced Rockets (CSAR) is housed within the Computational Science and Engineering Program (CSEP), an interdisciplinary program spanning 12 departments that range from astronomy to theoretical and applied mechanics. The Center for Novel Energetic Materials to Stabilize Rockets (CNEM), sponsored by the U.S. Ballistic Missile Defense Office and the Office of Naval Research, provides specific technical design expertise and experimental validation of results, significantly leveraging the DOE-funded program.

CSAR is a microcosm of a DOE data processing laboratory in that it has designers/customers and interdisciplinary teams of scientists and researchers whose goal is to provide the designers with integrated simulation tools to evaluate various design options. Its activities and resources are organized to support integrated simulation of rocket systems as the central objective. Complex simulations of subscale physics are also being carried out that use many of the same software components developed for the system simulation.

Comprehensive simulation will provide a much safer and less expensive way to investigate technical issues in rocket design than traditional methods based on experimental trial and error. Improved understanding of the behavior of solid propellant rockets will also have direct benefits for closely related technologies, such as gas generators used for automobile air bags and fire suppression, as well as many other technological design problems that involve complex components and require similar levels of system integration. The computational capabilities developed to support this effort will be applicable to a wide variety of important problems in computational science and engineering, including fluid dynamics, combustion, and failure of materials. CRPC Researcher Dan Reed leads the Computer Science Group in this effort.

For more information, see www.csar.uiuc.edu/F_info/AboutCSAR.html

Compilers, Tools, and Runtime Technology for Terascale Systems

The Rice University ASCI Level 2 Alliance Project coordinates efforts targeting two research thrusts: compilers and tools for improving memory hierarchy performance of complex application codes, and support for portable shared-memory programming on clusters of workstations and shared-memory multiprocessors.

The objective of the compilers and tools project is to conduct research on programming environment technology that facilitates optimization of ASCI applications for a range of current and future teraflop-scale architectures. The research is motivated by the challenges of obtaining very high sustained performance on highly parallel systems with complex multi-level memory hierarchies. The specific focus is on software technology to support both automatic and interactive optimization of codes written using the explicitly parallel programming models used by ASCI scientists.

Led by CRPC Director Ken Kennedy, this project builds on a decade of research experience in combining advanced compiler techniques and interactive tools for various dialects of Fortran, including Fortran 90, PCR Fortran, and High Performance Fortran (HPF). The major compilers and tools will leverage results from previous projects at Rice, particularly ParaScope and the D System.

For more information, contact John Mellor-Crummey at johnmc@cs.rice.edu.

The Delphi Project

Directed by CRPC researcher Andrew B. White Jr. at LANL, the Delphi Project provides a capability for generating the information and infrastructure necessary for making informed, science-based decisions on questions of national importance. It will strengthen and expand on the simulation capabilities that support ASCI and the DOE Defense Program's Science-Based Stockpile-Stewardship Program.

Delphi Project participants are involved in research that addresses complex questions in national security, national economic policy, international affairs, disaster mitigation, and science and engineering that cannot be directly answered through the traditional scientific method of theory, experiment and observation. The application areas explored by the Delphi Project include global climate modeling and other complex problems of strategic significance.

According to the researchers, the best means available to study and quantify climate change involves computer modeling that couples atmospheric and oceanic general circulation models with component models for sea-ice, land-surface, and other physical and chemical processes. However, present-day coupling climate models use inadequate horizontal resolutions. The spacial resolution in the atmosphere is too coarse to evaluate regional climate effects, and the resolution in the ocean is too coarse to adequately resolve mesoscale eddies and western boundary currents such as the Gulf Stream. LANL recently completed a high-resolution simulation of the Atlantic Ocean, which demonstrated that mesoscale eddies and western boundary currents require a much finer grid spacing for adequate resolution.

Other Delphi Project research involves forecasting natural hazards, managing disasters, and protecting critical infrastructure, such as transportation, electrical power, telecommunications, banking, and finance. The capability to view the entire national infrastructure as a "system of interrelated systems" has not yet existed, but it is needed to conduct contingency analyses, vulnerability studies, and investment option assessments. It is a problem of enormous scope and challenge that includes the actions and responses of intelligent human actors in the simulation.

For more information, see www.lanl.gov/delphi

For more information on the ASCI/ASAP Program, see www.llnl.gov/asci-alliance