Implicit Monte Carlo radiative transfer in DRACO

An Implicit Monte Carlo (IMC) transport module for two- dimensional non-orthogonal mesh, multi-frequency radiative transfer is presented. This module has been implemented in the DRACO radiation hydrodynamics laser fusion target simulation code. In the IMC method a forward plasma temperature is estimated at the beginning of the time step in the transport equation using the so-called Fleck factor to provide for an implicit solution for long time steps. A simple equilibrium solution in an infinite medium is used as an analytical benchmark of this implicit solution. In other dynamic test cases, analytical macroscopic cross sections are applied to compare with previously reported one-dimensional results by Fleck and Cummings. Finally, our IMC results are compared to the flux-limited multi-frequency diffusion model for uniform and non-uniform meshes in two dimensions.