Plasma screening in mid-charged ions observed by K-shell line emission

TL;DR

This study experimentally measures plasma screening effects on mid-charged ions using x-ray free electron laser data, providing insights into atomic physics in Warm Dense Matter and improving existing models.

Contribution

First experimental quantification of plasma screening effects on K-shell line emissions in mid-charged ions using XFEL data.

Findings

Energy shifts of K-shell lines observed

Identification of detailed electronic configurations

Advancement in plasma screening modeling

Abstract

Dense plasma environment affects the electronic structure of ions via variations of the microscopic electrical fields, also known as plasma screening. This effect can be either estimated by simplified analytical models, or by computationally expensive and to date unverified numerical calculations. We have experimentally quantified plasma screening from the energy shifts of the bound-bound transitions in matter driven by the x-ray free electron laser (XFEL). This was enabled by identification of detailed electronic configurations of the observed K{\alpha}, K\b{eta} and K{\gamma} lines. This work paves the way for improving plasma screening models including connected effects like ionization potential depression and continuum lowering, which will advance the understanding of atomic physics in Warm Dense Matter regime.