Density and temperature dependence of the cross sections after excitation of Ar XVIII by electron impact

We propose a novel distorted wave approach within the fundamental framework of relativity theory to calculate the dynamics of magnetic sublevels excitations of highly charged ions by electron impact within a quantum plasma. These cross sections can be used to predict the alignment parameter and subsequent angular pattern of the photoemission. Two kinds of modified Shukla and Eliasson [Phys. Rev. Lett. 108, 165007 (2012)] models, based on the quantum hydrodynamic theory, are adopted to determine the effects of screened Coulomb interaction among charged particles. The bound and continuous state (radial) wave functions are addressed through the one-dimensional Dirac equations, where the numerical convergence is checked. As an application, the 1s1∕2 → 2p3∕2 transition in Ar XVIII is used as a probe for the assessment of the quantum plasma shielding effects and the exchange-correlation effects on the energies, excitation cross sections, alignment parameters, and angular patterns of x-ray emission vs electron densities, from 1019 to 1024 cm−3, and compared to existing data. Our results highlight that the inclusion of the effect of plasma density and temperature not only leads to a significant reduction in the magnetic sublevels cross section, but also produces a change in the alignment parameter and angular pattern of the photoemission. The exchange-correlation effect is found to be crucial to the atomic structure, yet it weakens in the scattering process. In addition to insights into collision dynamics, this study opens the door to a further understanding of the polarization and angular distribution properties of x-ray radiation under extreme conditions. The present study is of interest for the warm density matter physics and high-energy density physics applications. The obtained atomic structure, sublevel cross section, and angular pattern of the photoemission are essential fundamental properties for advanced diagnostics and equation of state calculations in planet interior, inertial confinement fusion, and Z pulsed power facility.