K$_\alpha$ Emission Profiles of Warm Dense Argon Plasmas

TL;DR

This paper investigates K-alpha emission profiles from warm dense argon plasmas to diagnose temperature gradients and plasma effects, using a quantum statistical approach that improves upon existing models like FLYCHK.

Contribution

It introduces a quantum statistical method to analyze plasma screening effects on emission spectra, providing more detailed temperature-density relations than previous models.

Findings

Good reproduction of spectral features influenced by ionization and excitation.

More accurate temperature distribution inference compared to FLYCHK.

Revealed significant plasma effects on emission energies.

Abstract

K-line profiles emitted from a warm dense plasma environment are used for diagnostics of Ar droplet plasmas created by high energy laser pulses. Analyzing the temporally and spacially integrated spectra, we infer temperature gradients within the Ar droplet from cold temperatures of the order of some 10 eV up to higher temperatures of 250 eV and beyond. To characterize the influence of the warm and dense environment on the emitters, plasma screening is considered within a perturbative approach to the Hamiltonian. The plasma affects the many-particle system resulting in energy shifts of emission as well as ionization energies due to electron-ion and electron-electron interaction. With this approach we get a good reproduction of spectral features that are strongly influenced by ionization and excitation processes within the plasma. Comparing with the widely known FLYCHK code and the temperature distribution given in the original paper, counting for internal degrees of freedom (bound states) and treating pressure ionization within our quantum statistical approach results in a more detailed temperature-density-relation and leads to different results for the inferred temperature distribution.