High speed multi-ion interpenetration in a plasma fluid approximation

We continue investigations using numerical simulations of high-speed multi-ion interpenetration in a plasma fluid approximation for analysis of hohlraum physics and other low density multi-ion physics applications. A 1D test code is used to develop the methodologies for implementation in a full-physics AMR radiation hydrodynamics code, xRAGE. Issues of particular interest include the species collision rates at high drift speeds coupling species momentum, kinetic energies and thermal energies, the formulation of the electric field from the ambipolar electron momentum equation, electron-ion equilibration rates, and the inclusion of the plasma viscosity which requires implementation of energy conservation in two forms including both the species internal energy (for viscous heating) and the species total energy (for the viscous tensor work done on the fluid). Solutions for the inviscid case in a 1D hohlraum test problem have examined gold blow-off from the hohlraum wall colliding with a CH capsule expansion into the hohlraum cavity with a low density helium background. We expect to compare the inviscid and viscous plasma transport solutions, and alternate formulations for the ambipolar electric field. Several new variables and code modifications are underway to implement these physics options within xRAGE.