The Role of Non-Local and Non-Equilibrium Physics in High Energy Density Plasmas

Thomas Mehlhorn
United States Naval Research Laboratory
Center for Computational Science

There is a large class of problems in high energy density plasmas where the approximations of locality and equilibrium are invalid. In this talk I will consider three different systems: 1) K-shell Z-pinch radiation sources are not in LTE (local thermal dynamic equilibrium) and where non-local line radiation transport affects the plasma dynamics; 2) in laser generated plasmas, the mean free path of the heat conducting electrons can be greater than the temperature gradient scale length and the classical, local model can be invalid; and 3) when atomic clusters are irradiated by high-intensity ultrashort laser pulses the electric field of the laser is orders of magnitude greater than the Bohr electric field associated with the atoms, the ionization kinetics is time dependent (non-equilibrium), and all the tools and methodologies used in the isolated atom regime are negated. Simulating HED plasmas in LTE and where local transport is valid can be challenging to algorithms, databases, and computational hardware. Including these non-local and non-equilibrium effects is even more formidable, requiring trade-offs to be made between physics fidelity and computationally practicality. The choice of computational algorithm (e.g. hydrodynamics, particle-in-cell, or molecular dynamics; or diffusion, Krook, or Fokker Planck) is highly dependent upon the specific problem and degree of non-locality. This talk will provide an overview of each of these systems and their applications, the role of non-local and non-equilibrium physics, the computational physics challenge of including these effects, and a roadmap for future improvements.

• J.W. Thornhill, J.L. Giuliani, A. Dasgupta, et al., IEEE Trans. Plasma Sci., 38, 606 (2010).
• G.M Petrov, J. Davis, Phys. Plasmas 15, 056705 (2008)
• W. Mannheimer: APS DPP 2011:

In collaboration with A Dasgupta, J Davis, J Giuliani, W Mannheimer, and G Petrov, L Petrova, W Thornhill

Presentation (PDF File)

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