Multigroup Radiation Magnetohydrodynamics Based on Discrete Ordinates including Compton Scattering

Abstract We present a formulation and numerical algorithm to extend the scheme for gray radiation magnetohydrodynamics (MHD) developed by Jiang include frequency dependence via multigroup approach. The entire space can be divided into an arbitrary number of groups in lab frame, we follow time-dependent evolution frequency-integrated specific intensities along discrete rays inside each group. Spatial transport photons is done frame while all coupling terms are solved fluid rest frame. Lorentz transformation used connect different frames. equation fully implicitly time MHD equations evolved explicitly so that step not limited speed light. A finite volume approach both spatial spaces conserve energy density momentum. includes photon absorption, electron scattering, as well Compton which calculated solving Kompaneets equation. accurate wide range optical depth conditions handle radiation-pressure- gas-pressure-dominated flows. It works Cartesian curvilinear coordinate systems with adaptive mesh refinement. provide variety test problems including radiating sphere, shadow test, absorption moving gas, Bondi-type flows, collection thermal bulk scattering. also discuss examples where make big difference compared