Plasma Effects on Resonant Phenomena

TL;DR

This paper reviews the impact of autoionizing resonances on plasma phenomena, emphasizing theoretical methods for calculating opacities and reaction rates in high-energy-density plasmas relevant to astrophysics and fusion.

Contribution

It introduces a new approach for incorporating broadening mechanisms in resonance calculations within plasma environments, enhancing accuracy in opacity and reaction rate predictions.

Findings

Resonance effects significantly influence plasma opacity calculations.

The new method improves modeling of collisional and broadening effects in high-energy-density plasmas.

Reaction rates are notably affected by detailed resonance treatment.

Abstract

The effect of autoionizing resonances in atomic systems and processes is reviewed. Theoretical framework for treating resonances in the coupled channel approximation using the R-matrix method, as well as approximations related to plasma applications are described. The former entails large-scale atomic computations, and the latter is based on a new method for including collisional, Stark, thermal and other broadening mechanisms. We focus particularly on the problem of opacities calculations in high-energy-density (HED) plasmas such as stellar interiors and inertial confinement fusion devices. The treatment is generally relevant to radiative and collisional processes as the cross sections become energy-temperature-density dependent. While the computational difficulty increases considerably, the reaction rates are significantly affected. The related issue of the Boltzmann-Saha equation-of-state and its variants in local-thermodynamic-equilibrium (LTE) is also explored as the intermediary between atomic data on the one hand and plasma environments on the other.