Mesh-free simulation of long-range N-body systems with parallel tree codes

Datum

11.01.2012

Zeit

17:00 - 18:00

Sprecher

Paul Gibbon

Zugehörigkeit

Forschungszentrum Juelich

Sprache

en

Hauptthema

Physik

Andere Themen

Physik

Host

IMPRS Seminar

Beschreibung

Numerical plasma modeling traditionally involves one of two different approaches: i) the fluid approach, which delivers information on ‘macroscopic’ scales; or ii) kinetic particle simulation, which can resolve nonlinear wave-particle interaction and ‘non-Maxwellian’ behavior. Both of these techniques typically rely on the use of a spatial mesh to solve a set of coupled partial differential equations for the fluid or particle properties. Recently a new modeling paradigm has been established – mesh-free plasma simulation [1] – in which fast summation techniques replace the solution of the field equations on the mesh. The key innovation behind this development is the hierarchical tree algorithm, a rapid O(N log N) technique for evaluating mutual (Coulomb) forces due to an ensemble of charged particles. At JSC we have developed a parallel tree-code (PEPC) capable of running on the entire 294912 processors of the BlueGene/P supercomputer Jugene [2], a milestone which makes it feasible to perform ab initio electrostatic molecular dynamics simulations using well over 109 particles. Applications of this code to various topical problems in plasma physics will be demonstrated, including: simulations of ion acceleration by high intensity lasers, heating and dynamics of nanostructured targets, and modeling of edge-plasmas in tokamaks. Besides electrostatics, the present tree code is also being applied to other ‘action-at-a-distance’ problems, such as vortex fluids, astrophysical objects and magnetoinductive ‘Darwin’ plasmas, examples of which will also be shown. [1] P. Gibbon, R. Speck, A. Karmakar, L. Arnold, W. Frings, B. Berberich, D. Reiter, M. Mašek, Progress in Mesh-Free Plasma Simulation With Parallel Tree Codes, IEEE Transactions on Plasma Science 38, 2367–2376, (2010). [2] M. Winkel, R. Speck, H. Hübner, L. Arnold, R. Krause, P. Gibbon, A massively parallel, multi-disciplinary Barnes-Hut tree code for extreme-scale N-body simulations, Comp. Phys. Commun. (2011, in press).

Letztmalig verändert: 11.01.2012, 08:35:32