Molecular Dynamics of Hot, Dense Radiative Plasmas

Frank Graziani
Lawrence Livermore National Laboratory

In large multi-physics codes describing the transport of radiation in plasmas, physics models such as ion stopping power or energy exchange rates are computed from a kinetic equation (e.g. Fokker-Planck, Lenard-Balescu, etc). How does one validate these models in regimes that are experimentally inaccessible? Such is the case for hot, dense radiative plasmas where temperatures can range from hundreds to thousands of electron volts and densities from one to hundreds of gm/cm3. These plasmas are characterized by being multi-species (electrons, protons, partially ionized ions) and having photon transport, atomic processes and thermonuclear burn. Particle collisions are governed by classical many-body effects at large distances and quantum mechanical effects at short distances

An alternative approach to the experimental validation of models derived from kinetic equations, is to use molecular dynamics to numerically compute the solution of the associated Liouville equation. In other words, use the computer to create the virtual world of a plasma. We show how classical molecular dynamics with effective two body potentials can be used to investigate charged particle energy coupling rates. We discuss the benefits and challenges of this approach. We discuss the extension of classical molecular dynamics to the quantum mechanical regime using Wigner functions and wave packet molecular dynamics.

Presentation (PowerPoint File)

Back to Workshop I: Computational Kinetic Transport and Hybrid Methods