MONTE CARLO RADIATION-HYDRODYNAMICS WITH IMPLICIT METHODS

Abstract

We explore the application of Monte Carlo transport methods to solving\ncoupled radiation-hydrodynamics problems. We use a time-dependent,\nfrequency-dependent, 3-dimensional radiation transport code, that is special\nrelativistic and includes some detailed microphysical interactions such as\nresonant line scattering. We couple the transport code to two different\n1-dimensional (non-relativistic) hydrodynamics solvers: a spherical Lagrangian\nscheme and a Eulerian Godunov solver. The gas-radiation energy coupling is\ntreated implicitly, allowing us to take hydrodyanimcal time-steps that are much\nlonger than the radiative cooling time. We validate the code and assess its\nperformance using a suite of radiation hydrodynamical test problems, including\nones in the radiation energy dominated regime. We also develop techniques that\nreduce the noise of the Monte Carlo estimated radiation force by using the\nspatial divergence of the radiation pressure tensor. The results suggest that\nMonte Carlo techniques hold promise for simulating the multi-dimensional\nradiation hydrodynamics of astrophysical systems.\n