Approximate Riemann Solver for the Electronic M₁ Model Without Electric Field in the Diffusive Limit

ABSTRACT

This work is devoted to the derivation of an approximate Riemannsolver for the electronic M₁ model without electric field in the diffusive regime. The derivation of the scheme is based on an approximate Riemann solver, where the intermediate states are chosen consistent with the integral form of the approximate Riemann solver. This choice can be modified to enable the derivation of a numerical scheme which satisfies the admissible conditions and enjoys asymptotic-preserving properties recovering the correct diffusion equation. Numerical tests cases are presented and the asymptotic-preserving scheme is compared to the classical HLL (Harten et al., 1983) scheme usually used for the electronic M₁ model.

Keywords:

• Approximate Riemann solvers
• asymptotic preserving schemes
• diffusive limit
• Godunov type schemes
• moment model
• plasma physics