Model comparisons for high-Z non-LTE steady-state calculations

Abstract

Advances in computer technology and code development have made it possible to perform plasma kinetics calculations based on high- Z atomic structure corresponding to different levels of detail. Various atomic models have been implemented in the Los Alamos suite of codes in recent years for performing detailed non-equilibrium kinetics calculations. These include non-relativistic configuration average models with unresolved transition arrays (UTA), detailed fine structure models including configuration interaction and intermediate coupling that are capable of achieving spectroscopic accuracy for low- Z plasmas, and fully relativistic configuration average models employing the concept of the unresolved transition array, UTA, for modeling high- Z plasmas. Fully relativistic fine structure calculations have also been implemented and used primarily for accuracy checks. In addition, the fractional occupation number method has been introduced in the relativistic structure code to reduce computational times without reducing data quality. Finally, we will discuss a method that has been developed to use the populations extracted from a non-relativistic kinetics calculation in a relativistic spectral simulation. The purpose of the present work is to compare the emission spectra predicted by the various models and methods using consistent sets of atomic electron configurations and cross-sections for a gold plasma.