Atomic structure data based on average-atom model for opacity calculations in astrophysical plasmas

Abstract

Influence of the plasmas parameters on the electron structure of ions in astrophysical plasmas is studied on the basis of the average-atom model in the local thermodynamic equilibrium approximation. The relativistic Dirac–Slater method is used for the electron density estimation. The emphasis is on the investigation of an impact of the plasmas temperature and density on the ionization stages required for calculations of the plasmas opacities. The level population distributions and level energy spectra are calculated and analyzed for all ions with 6 ≤ Z ≤ 32 occurring in astrophysical plasmas. The plasma temperature range 2−200 eV and the density range 2−100 mg/cm3 are considered. The validity of the method used is supported by good agreement between our values of ionization stages for a number of ions, from oxygen up to uranium, and results obtained earlier by various methods among which are more complicated procedures.