Physics-Based Computational Algorithm for the Multi-Fluid Plasma Model

Abstract

Abstract : A physics-based algorithm is developed based on the multi-fluid plasma model derived from moments of the Boltzmann equation. The model includes evolution equations for the electromagnetic fluids, electron fluid, ion fluid, neutral fluid, and any additional species. The large mass difference between electrons and ions introduces disparate time and spatial scales and requires a numerical algorithm with sufficient accuracy to capture the multiple scales. In addition, the characteristic time scales for the electromagnetic fields is much shorter than the time scales of the ion and neutral fluids. The physics-based computational algorithm solves fluid models for each plasma species that are appropriate for the expected physical behavior, by combining 5N-moment and 13N-moment fluid models for multicomponent plasmas. The numerical discretization is developed specifically to capture the expected physical behavior by combining high-order continuous and discontinuous spatial representations of the solution and implicit time-advance methods to accurately capture the fast and slow dynamics. The physics-based computational algorithm has also been extended to solving continuum kinetic plasma models. Solving Maxwell's equations has been improved by using a parabolic modification to ensure the errors of divergence constraint equations are properly removed and handled. Nonreflecting boundary conditions using a lacunae-based method have been implemented and provide higher solution fidelity for open boundary problems.