The impact of multipole and relativistic effects on photoionization and radiative recombination cross sections in hot plasmas

TL;DR

This paper demonstrates that relativistic and multipole effects significantly influence photoionization and radiative recombination cross sections in hot plasmas, emphasizing the importance of relativistic electron distributions for accurate rate calculations.

Contribution

It introduces a fully relativistic Dirac-Fock approach that accounts for all multipoles and highlights the necessity of using relativistic Maxwell-Boltzmann distributions in hot plasma modeling.

Findings

Multipole contributions are significant at electron energies above several keV.

Relativistic Maxwell-Boltzmann distribution reduces recombination rate coefficients.

First demonstration of the combined impact of relativistic effects and multipoles in this context.

Abstract

It is shown in the framework of the fully relativistic Dirac-Fock treatment of photoionization and radiative recombination processes that taking into account all significant multipoles of the radiative field is of considerable importance at electron energy higher than several keV. For the first time, we show that the relativistic Maxwell-Bolzmann distribution of continuum electrons should be used in hot thermal plasmas. This decreases the radiative recombination rate coefficient up to several multipoles compared to the non-relativistic distribution commonly used.