Non-LTE radiation transport in moderate-density plasmas

Abstract

We present results from non-LTE line radiation transport calculations for high-temperature, optically thick plasmas with densities ∼1016-1020 ions/cm3. The calculations are based on an escape probability radiative transport model in which the atomic rate equations are solved self-consistently with the radiation field. Steady-state ionization and excitation populations are determined by detailed balancing of atomic processes, with photoexcitation effects included. Atomic data are computed using a combination of Hartree-Fock, semiclassical impact-parameter, and distorted-wave calculations. Our results indicate that the reabsorption of line radiation significantly alters the level populations and reduces the radiation flux from several types of fusion-related plasmas. We also compare our results with those obtained from multigroup radiation diffusion calculations, and discuss the ramifications of our results for ICF target chamber plasmas.