Avalidation Test of the Flux-limited Diffusion Approximation for Radiation Hydrodynamics

This paper presents a validation test of the flux-limited diffusion (FLD) approximation for radiation hydrodynamics in the intermediate optical depth regime. We use an implementation of FLD in the ZEUS-2D astrophysical fluid dynamics code and the results of a set of laser-driven radiative shock experiments. One-dimensional simulations are performed to explore grid spacing and time step convergence without being limited by the available computational resources. The validation test compares two-dimensional simulations with the experimental results. FLD passes the validation test with a qualification: time step convergence seems very demanding for this particular problem. Given this qualification, it is uncertain whether FLD is faster than full-transport or other methods in the intermediate optical depth regime. Subject headingg s: hydrodynamics — methods: numerical — radiative transfer Online material: machine-readable tables