Impact of super-Gaussian electron distributions on plasma K-shell emission

TL;DR

This paper investigates how super-Gaussian electron distributions in laser-produced plasmas influence K-shell emission spectra, revealing that spectroscopy can diagnose non-equilibrium electron distributions.

Contribution

It provides a detailed analysis of the effects of super-Gaussian electron distributions on plasma K-shell emission and proposes spectroscopy as a diagnostic tool.

Findings

Super-Gaussian distributions slightly alter plasma ionization.

K-shell spectra are significantly affected by non-equilibrium distributions.

Spectroscopy can infer the presence of super-Gaussian electron distributions.

Abstract

Electron distributions in laser-produced plasmas will be driven toward a super-Gaussian distribution due to inverse bremsstrahlung absorption [Langdon, Phys. Rev. Lett. 44, 575 (1980)]. Both theoretical and experimental evidence suggest that fundamental plasma properties are altered by the super-Gaussian distribution. This paper examines how the super-Gaussian distribution affects the ionization balance and K-shell emission of atomic plasmas, utilizing approximate formulas and detailed collisional-radiative simulations. While the impact on plasma ionization is small, K-shell spectra can be significantly modified. Based on these findings, we demonstrate that K-shell spectroscopy can be used to infer super-Gaussian or other similar non-equilibrium electron distributions.