Angular Distribution and Linear Polarization of X-ray Radiation Resulting from Electron Impact Excitation of Highly Charged Ions in Debye Plasmas

Abstract

Plasma-screening effects on the $$1s _{1/2} \rightarrow 2l \; (l = s , p )$$ and $$1s _{1/2} \rightarrow 3d _{3/2}$$ electron-impact excitation of highly charged ions are investigated, together with their subsequent radiative decay. The analysis is performed based on the multi-configuration Dirac–Fock method and the fully relativistic distorted-wave method incorporating the Debye–Huckel potential. To explore the nature of the effects, calculations are carried out based on detailed analyses of the integrated total and magnetic sublevel cross sections, the alignment parameters, the linear polarizations, and the angular distribution of the X-ray photoemission, as well as on corresponding data calculated in various Debye lengths/environments, taking the $$2p _{3/2}\rightarrow 1s _{1/2}$$ and $$3d _{3/2}\rightarrow 1s _{1/2}$$ characteristic lines of H-like $$\hbox {Fe}^{25+}$$ ion as an example. The present results are compared with experimental data and other theoretical predictions where available.