Statistical screening model for moderately coupled and dense plasmas

TL;DR

This paper introduces a new statistical model for electron screening in dense, moderately to strongly coupled plasmas, improving spectral predictions and accounting for multi-body effects.

Contribution

The model incorporates three-body processes and state-dependent effects, providing more accurate plasma electron distributions and spectral line shifts than previous models.

Findings

Better agreement with experimental spectral line shifts.

More accurate low-energy electron distribution modeling.

Enhanced description of multi-body effects in dense plasmas.

Abstract

For atoms embedded in dense plasma, the plasma screening effects will greatly alter their structure and dynamics, and then determine the radiation transport properties of the plasma. In the present work, a new statistical model is proposed for treating electron screening effects on atoms in moderately/strongly coupled and dense plasmas, in which the three-body processes are found to significantly influence the plasma-electron density distributions and leads to a dependence of the distribution on the specific bound state of the targeted atom. As a critical check, the model is applied to simulate the emission spectra of He-like Aluminum and Chlorine in hot dense plasmas, and much better agreements of the line shifts are obtained with the experiments of Stillman et al. in 2017 and Beiersdorfer et al. in 2019 than previous calculation results. Compared with the classical molecular dynamic simulations of electron distributions in moderately coupled plasmas, the present model can better describe the low-energy electron distribution than other models and the multi-body effects are well considered. The present model provides a promising tool to reasonably treat the electron screening effect of non-equilibrium dense plasma on atoms with specific bound states, which is urgently needed in high-precision simulations of the atomic processes, plasma spectra and radiation transport properties etc.