High-fidelity plasma simulations using a domain-hybridized model

High-fidelity simulations of plasma dynamics can involve various mathematical formulations, including the multi-species (electrons, ions, and neutrals) 5$N$-moment fluid model and the continuum kinetic model.  This work combines these models in a single domain-decomposed hybrid model where multiple formulations are used in a single simulation.  Special attention is given to the development of interface boundary conditions between formulations and determination of the parameter regimes most appropriate for each to maintain sufficient physical fidelity over the whole domain while minimizing computational expense.  The WARPXM framework developed at the University of Washington which implements these formulations using a discontinuous Galerkin spatial discretization on unstructured meshes is being used to develop the domain-decomposed hybrid model.  Simulations involving a double rarefaction wave, a plasma sheath, and the magnetized Kelvin-Helmholtz instability are presented, showing the viability of the domain-hybridized model.  In addition, linear analysis and kinetic simulations of the Dory-Guest-Harris instability are presented for the Vlasov-Maxwell continuum kinetic model, highlighting a method for benchmarking of kinetic codes for electromagnetic problems.