Implicit-explicit Runge-Kutta for radiation hydrodynamics I: Gray diffusion

Ben S. Southworth, Hyeongkae Park, Svetlana Tokareva, Marc Charest

Abstract: Highlights•Implicit-explicit Runge-Kutta integration for hydrodynamics coupled to gray radiation diffusion.•Develop temperature closure to treat non-stiff nonlinear coupling in opacity explicitly.•2nd-order accuracy observed on radiative shocks.•Error 3–5 orders of magnitude smaller than Lie-Trotter operator split.