Radiative hydrodynamic equations with nonequilibrium radiative transfer

This paper presents a kinetic model for the coupled evolution of radiation, electrons, and ions in a radiation plasma system. The model is solved using two methods. The gas-kinetic scheme (GKS) for electron and ion hydrodynamics and the unified gas-kinetic scheme (UGKS) for nonequilibrium radiative transfer. The UGKS accurately captures multiscale photon transport from free streaming to diffusion across varying fluid opacities. This approach enables the scheme to model equilibrium plasma with nonequilibrium radiation transport. The model is validated through several test cases, including radiative transfer in kinetic and diffusion regimes, Marshak wave, radiative shock, three-temperature double lax shock tube problem, two-dimensional Sedov blast wave, and two-dimensional top hat based problem. These tests demonstrate the current scheme's capability to handle diverse radiation plasma scenarios.