Grand Challenge Problems in Computational Astrophysics

March 7 - June 10, 2005

Program Poster PDF

Participants

Organizing Committee

Willy Benz (Bern, Physikalisches Institut)
Phillip Colella (Lawrence Berkeley National Laboratory, Mathematics)
Richard Klein (University of California at Berkeley/Lawrence Livermore National Laboratory, Astronomy)
James McWilliams (UCLA, IGPP & Atmospheric Sciences)
Joseph Monaghan (Monash University, Australia, Mathematical Sciences)
Mark Morris (UCLA, Physics & Astronomy)
Stanley Osher (IPAM, Mathematics)
Chi-Wang Shu (Brown University, Applied Mathematics)
Harold Yorke (California Institute of Technology, Astrophysics)

Participants

This long-term program will involve a community of senior and junior researchers. The intent is for long-term participants to have an opportunity to learn about computational astrophysics from the perspectives of many different fields--mathematics, science and astronomy--and to meet a diverse group of people and have an opportunity to form new collaborations. In addition to these activities, there will be opening tutorials, three workshops, and a culminating workshop at Lake Arrowhead.

Full and partial support for long-term participants is available, and those interested are encouraged to fill out an online application at the bottom of this page. Support for individual workshops will also be available, and may be applied for through the online application for each workshop. We are especially interested in applicants who are interested in becoming core participants and participating in the entire program (March 7 - June 10, 2005), but give due consideration to applications for shorter periods. Funding for participants is available at all academic levels, though recent PhD's, graduate students, and researchers in the early stages of their career are especially encouraged to apply.

Encouraging the careers of women and minority mathematicians and scientists is an important component of IPAM's mission and we welcome their applications.

Activities

There will be an active program of research activities, seminars and workshops throughout the March 7 - June 10, 2005 period and core participants will be in residence at IPAM continuously for these fourteen weeks. The program will open with tutorials, and will be punctuated by three major workshops and a culminating workshop at UCLA’s Lake Arrowhead Conference Center. Several distinguished senior researchers will be in residence for the entire period. Between the workshops there will be a program of activities involving the long-term and short-term participants, as well as visitors. These activities will include:

• Tutorials. March 8 - 11, 2005.
• Workshop I: Astrophysical Fluid Dynamics. April 4 - 9, 2005.
• Workshop II: N-Body Problems in Astrophysics. April 18 - 22, 2005.
• Workshop III: Relativistic Astrophysics. May 2 - 6, 2005.
• Workshop IV: Transfer Phenomena. May 16 - 20, 2005.
• PCA Culminating Conference at Lake Arrowhead (By Invitation Only). June 5 - 10, 2005.

Between the workshops there will be numerous activities involving the long-term and short-term participants, as well as visitors. See IPAM Events calendar for details. Activities will include:

• Short courses and lecture series
  • Special Lecture: Antonio Marquina, University of Valencia. Introduction to shock capturing schemes for astrophysical hydro codes. March 16, 1:30 PM - 3:00 PM, IPAM Building, Room 1200.
  • Special Lecture: Antonio Marquina, University of Valencia. Introduction to shock capturing schemes for astrophysical hydro codes. March 18, 1:30 PM - 3:00 PM, IPAM Building, Room 1200.
  • AMR Focus Days. Organizer: Phil Colella.
    • March 21, 2:00 PM - 3:00 PM, IPAM Building, Room 1200. Dan Martin, LBNL. Introduction to Chombo and the Chombo AMRPoisson solver. Presentation (PDF File).
      
    • March 21, 3:30 PM - 5:00 PM, IPAM Oasis Area Plasma Screen. Dan Martin, LBNL. Demonstrations of Chombo AMRPoisson solver.
      
    • March 22, 9:00 AM - 5:00 PM, IPAM Oasis Area Plasma Screen. Dan Martin, LBNL. Demonstrations of Chombo AMRPoisson solver.
      
    • March 23, 9:00 AM - 12:00 PM, IPAM Oasis Area Plasma Screen. TBA.
      
    • March 28, 2:00 PM - 3:00 PM, IPAM Building, Room 1200. Terry Ligocki, LBNL. Chombo AMR Godunov interface and the ChomboVis visualization package. Presentation (PDF File).
      
    • March 28, 3:30 PM - 5:00 PM, IPAM Oasis Area Plasma Screen. TBA.
      
    • March 29, 9:00 AM - 5:00 PM, IPAM Oasis Area Plasma Screen. Terry Ligocki, LBNL. Demonstrations of the ChomboVis visualization package.
      
    • March 30, 9:00 AM - 12:00 PM, IPAM Oasis Area Plasma Screen. TBA.
      
  • Special Session on Coronal Heating: Marco Velli, University of Florence. Coronal Heating. March 28, 10:30 AM - 1:00 PM, IPAM Building, Room 1200.
  • PCA Miniworkshop - Supernovae Focus Day. April 11.
  • Mini-workshop MHD with SPH. April 12, 9:00 AM - 12:00 PM, IPAM Building, Room 1200. Speakers: Joe Monaghan, Sam Falle, Daniel Price, Steinar Borve.
• Discussion Groups (organizer: Sverre Aarseth)
  On Tuesdays of non-workshop weeks. First session on April 26. Meets 11:00 AM - 12:00 PM
  • April 26, 11:00 AM - 12:00 PM, IPAM Building, Room 1180. TBA.
    
• Special seminars and Participants' seminars (organizer: Mark Morris)
  Usually at 3:30-4:30 on wednesdays
  • March 17, 11:00 AM - 12:00 PM, IPAM Building, Room 1200. Marco Velli, University of Florence. Spherically symmetric accretion, winds and breezes , or, comments on why the solar wind is supersonic. Presentation (PowerPoint File).
    
  • March 22, 11:00 AM - 12:00 PM, IPAM Building, Room 1200. Christian Klingenberg , Bayerische-Julius-Maximilians-Universität Würzburg. Dust Modelling: Microscopic and Macroscopic.
    
  • March 23, 3:30 PM - 4:30 PM, IPAM Building, Room 1200. Michael Knoelker, National Center for Atmospheric Research. Some of the key problems in our understanding of the Sun Part I: Observations & Theory.
    
  • March 24, 3:30 PM - 4:30 PM, IPAM Building, Room 1200. Michael Knoelker, National Center for Atmospheric Research. Some of the key problems in our understanding of the Sun Part II: Grand Challange problems in Numerical Modelling .
    
  • March 30, 3:30 PM - 4:30 PM, IPAM Building, Room 1200. Christian Klingenberg , Bayerische-Julius-Maximilians-Universität Würzburg. Accretion Disk Simulations from a Mathematician's point of view. Presentation (PDF File).
    
  • March 31, 4:00 PM - 5:00 PM, IPAM Building, Room 1200. Jens Niemeyer, University of Wuerzburg. Combining AMR and LES for Simulations of Astrophysical Turbulence.
    
  • April 13, 3:30 PM - 4:30 PM, IPAM Building, Room 1200. Lia Athanassoula, Université d'Aix-Marseille I (Université de Provence). Dynamical Evolution of Barred Galaxies.
    
  • April 14, 2:00 PM - 3:00 PM, IPAM Building, Room 1200. Yann Rasera, CEA Saclay, France. AMR Cosmological Simulations: the History of the Baryon Budget.
    
  • April 15, 2:00 PM - 3:00 PM, IPAM Building, Room 1200. Yurii Dumin, Russian Academy of Sciences. N-Body Dynamics of Strongly-Coupled (Nonideal) Plasmas.
    
  • April 26, 11:00 AM - 12:00 PM, IPAM Building, Room 1180. TBA.
    
  • April 27, 3:30 PM - 4:30 PM, IPAM Building, Room 1200. Jonathan Dursi, University of Toronto. Astrophysical Thermonuclear Flames & their Instabilities.
    
  • April 29, 2:00 PM - 3:00 PM, IPAM Building, Room 1200. Yurii Dumin, Russian Academy of Sciences. Testing the "Dark-Energy"-Dominated Cosmological Models via the Solar-System Experiments.
    
  • May 10, 11:00 AM - 12:00 PM, IPAM Building, Room 1180. Sverre Aarseth, University of Cambridge. N-Body Treatment of Binaries.
    
  • May 12, 11:00 AM - 12:00 PM, IPAM Building, Room 1180. Sverre Aarseth, University of Cambridge. N-Body Treatment of Binaries - Continued.
    
  • May 12, 2:00 PM - 3:00 PM, IPAM Building, Room 1200. Benjamin M. Zuckerman, UCLA. High-Resolution Imaging of Young Planets.
    
  • May 13, 11:00 AM - 12:00 PM, IPAM Building, Room 1200. Nelly Mouawad, American University of Beirut. Mass Distribution at the Galactic Center.
    
  • May 23, 2:00 PM - 3:00 PM, IPAM Building, Room 1180. Sverre Aarseth, University of Cambridge. N-body treatment of binaries and triples.
    
  • May 25, 3:30 PM - 4:30 PM, IPAM Building, Room 1200. Joel Tohline, Louisiana State University. Modeling Unstable Mass-Transfer in Close Binary Star Systems.
    
  • May 26, 2:00 PM - 3:00 PM, IPAM Building, Room 1180. Sverre Aarseth, University of Cambridge. N-body treatment of binaries and triples.
    
  • May 26, 3:00 PM - 4:00 PM, IPAM Building, Room 1200. Fabio Iocco, National Institute of Nuclear Physics (INFN). Primordial Nucleosynthesis.
    
  • May 27, 10:00 AM - 11:00 AM, IPAM Building, Room 1200. Tim Brown, National Center for Atmospheric Research/High Altitude Observato. Atmospheres of extra Solar Planets and related pleasures.
    
• Junior seminars (organizers: Kurt Sebastian and Matthew Turk)
  Usually at 4-5 on tuesdays and 11-12 on thursdays
  • March 29, 4:00 PM - 5:00 PM, IPAM Building, Room 1180. Kurt Sebastian, U.S. Coast Guard Academy. . Presentation (PDF File).
    
  • April 28, 4:00 PM - 5:00 PM, IPAM Building, Room 1200. Fabio Iocco, National Institute of Nuclear Physics (INFN). Primordial Nucleosynthesis.
    
  • May 10, 4:00 PM - 5:00 PM, IPAM Building, Room 1180. Matthias Schaefer, Universität Kaiserslautern. Partial Space Moment Approximations for Radiative Transfer.
    
• Related UCLA seminars
  • Applied math colloquium: usually at 4-5 on wednesdays

Scientific Background

The 20^th century saw the culmination of efforts to solve the major theoretical problems of astrophysics using analytical techniques. Indeed, most of the basic underpinnings of our current understanding of stellar and galactic dynamics, gas dynamics, stellar evolution, and planetary dynamics, were laid out by the heroic efforts of several generations of theorists from Eddington, Chandrasekhar, Schwarzchild and Milne to the likes of Parker, Mestel, Zel’dovich, Ostriker, Goldreich, Rees, Shu and Blandford. However, the complexity of most astrophysical phenomena dictates that accessible analytical techniques are increasingly becoming relegated to limiting cases. In a realistic and complete description of most cosmic phenomena, one must typically face highly non-linear interactions between objects or particles, as well as non-linear couplings between different kinds of interactions, including gravitational, electromagnetic, radiative, and gas dynamical interactions. Consequently, numerical approaches to understanding astrophysical phenomena have become indispensable, and promise to dominate the methodology of theorists well into the 21^st century and presumably beyond.

The sophistication and the diversity of computational methods have grown alongside the power of computers, but there has emerged the perception amongst some theorists that we have reached certain roadblocks in this evolutionary process. While technical advances continue to be made, including massive parallelization and the development of dedicated special-purpose computers, such as GRAPE, investigators have encountered various algorithmic limitations. With the possible exception of some novel methodologies currently being explored, future progress in computational theory appears to be awaiting only the inexorable increase in raw computing power. The most advanced coding techniques, including adaptive mesh refinement (AMR), N-body tree codes, and smoothed particle hydrodynamics (SPH) and its offshoots, have been very successful, but their accuracy in the 3-dimensional realm is often problematical, especially over long time spans. The devil is often in the unresolved, small-scale details of such physical processes as turbulent cascades, turbulent energy dissipation, magnetic field line reconnection, narrow shock fronts and dynamical instabilities, among others.

Consequently, this is an appropriate time for the community to examine these algorithmic limitations to see if creative, new ways can be found to circumvent them, either for limited ranges of problems, or across the board. We therefore propose a program at IPAM aimed at stimulating exchanges among computational astrophysicists and applied mathematicians. The program would be structured to identify the barriers to algorithmic efficiency and accuracy, and to provoke the participants to either find ways of surmounting those barriers or perhaps to decisively demonstrate that certain limitations are inherently unavoidable.

The topic of astrophysical theory is chosen for a couple of reasons: first, because it is at the forefront of the development of computational techniques, as has always been the case historically. Second, astrophysical theory is an inherently rich subject calling upon every conceivable brand of numerical analysis for a very broad range of phenomena. The range of subtopics below illustrates this point.

Of course, much of what is learned from this endeavor can be applied across the board to a variety of other subjects, such as meteorology and oceanography. We will nonetheless limit the scope of this program to exclude a few important computational astrophysics topics: data analysis techniques and astronomical imaging, because we judge those to be outside the domain of astrophysical theory proper. Astronomical imaging is, in any case, the focus of a separate IPAM workshop.

There have been occasional international conferences explicitly focused on computational astrophysics. For example, in March 1998, the International Conference on Numerical Astrophysics was held in Tokyo Japan. (Proceedings published by: S.M. Miyama, K. Tomisaka, T. Hanawa: 1999, Boston: Kluwer, Astrophysics and Space Science Library vol 240).

The upcoming IPAM program, however, will be the first to bring the numericists together with applied mathematicians.

Some of the topics that will be covered in the program are:

• Those dealing with numerical technique such as Finite difference codes and AMR, SPH, GPM, and other particle methods, and N-body codes.
• Those with a dominant astrophysical theme such as hydrodynamic and magnetohydrodynamic problems, gravitational problems (e.g., stellar dynamics), radiative transfer problems, and mixed problems: accretion disks, cosmological structure formation, star formation

Contact Us:

Institute for Pure and Applied Mathematics (IPAM)
Attn: PCA2005
460 Portola Plaza
Los Angeles CA 90095-7121
Phone: 310 825-4755
Fax: 310 825-4756
Email: ipam@ucla.edu
Website: http://www.ipam.ucla.edu/programs/pca2005/