J. R. White | Searcharxiv

arXiv2024

Dense Plasma Opacity from Excited States Method

The self-consistent inclusion of plasma effects in opacity calculations is a significant modeling challenge. As density increases, such effects can no longer be treated perturbatively. Building on a recently published model that addresses this challenge, we calculate opacities of oxygen at solar interior conditions. The new model includes the effects of treating the free electrons consistently with the bound electrons, and the influence of free electron energy and entropy variations are explored. It is found that, relative to a state-of-the-art-model that does not include these effects, the bound free-opacity of the oxygen plasmas considered can increase by 10%.

physics.plasm-ph↗

arXiv2024

Pseudoatom Molecular Dynamics Plasma Microfields

Spectral line profiles are powerful diagnostic tools for both laboratory and astrophysical plasmas, as their shape is sensitive to the plasma environment. The low-frequency component of the electric microfield is an important input for analytic line broadening codes. In this paper we detail a new method of calculating plasma microfields using configuration-resolved pseudoatom molecular dynamics. This approach accounts for both quantum atomic structure and N-body effects, similar to density functional theory molecular dynamics, but with less computational cost. We present pseudoatom microfields at conditions relevant for recent laboratory experiments. Compared to established microfield codes we find moderate deviations at solid density conditions and strong agreement at lower plasma densities.

physics.plasm-ph↗