Benchmarking multi-fluid plasma-electromagnetic models

Summary form only given. The dynamical behavior of plasmas is strongly dependent on frequency. At the lowest frequency the plasma is in the regime of magnetohydrodynamics (MHD) and has been the focus of extensive research in fluid plasma modeling in the past few decades. At somewhat higher frequencies, the electrons and ions can move relative to each other, behaving like two charge separated, interpenetrating fluids. This is the regime of high-frequency, non-neutral two-fluid physics and is relevant to high-density, fast MHD phenomena encountered in pulsed-power devices like dense plasma focus, Z-pinches, plasma thrusters and field-reversed configurations. Although initial work has been done on efficiently solving fast MHD phenomena, several open research problems remain. For example, implicit schemes developed for application in slow MHD can not be applied directly as pulsed-power devices commonly exhibit shocks and other sharp features in the flow. To meet this need, we have developed fully implicit schemes for solving the two fluid equations based on a combination of physics-based preconditioning and Jacobian-Free Newton Krylov solvers. Here, we present application of this approach to a range of problems, including shock physics, ambipolar expansion and shear flow. Results obtained from our approach will be compared to analytic theory and, where appropriate, magnetohydrodynamic and kinetic simulations.