Time-dependent X-ray polarization analysis for anisotropic distribution of hot electrons in ultrahigh intensity laser plasmas

Theoretical study of energy transfer in ultrahigh intensity laser plasma was performed using a computer code to analyze the polarization of the Cl–Heα line. The Breit–Pauli R-matrix method was used to calculate elastic- and inelastic-scattering cross-sections with magnetic sublevels by electron impacts for He-like and Li-like Cl ions, respectively. The dependence of polarization on the electron density was investigated by using a time-dependent, collisional-radiative atomic kinetics model for ion densities from intermediate region to near solid. It is found that the polarization degree decreases with increase in electron density due to dominance of elastic collisional process.