KAPPA: A Package for the Synthesis of Optically Thin Spectra for the Non-Maxwellian κ-Distributions. III. Improvements to Ionization Equilibrium and Extension to κ < 2

Abstract

The KAPPA package is designed for calculations of optically thin spectra for the non-Maxwellian κ -distributions. This paper presents an extension of the database to allow calculations of the spectra for extreme values of κ < 2, which are important for accurate diagnostics of the κ -distributions in the outer solar atmosphere. In addition, two improvements were made to the ionization equilibrium calculations within the database. First, the ionization equilibrium calculations now include the effects of electron impact multi-ionization (EIMI). Although relatively unimportant for Maxwellian distribution, EIMI becomes important for some elements, such as Fe and low values of κ , where it modifies the ionization equilibrium significantly. Second, the KAPPA database now includes the suppression of dielectronic recombination at high electron densities, evaluated via the suppression factors. We find that at the same temperature, the suppression of dielectronic recombination is almost independent of κ . The ionization equilibrium calculations for the κ -distributions are now provided for a range of electron densities.

Keywords

• Atomic spectroscopy
• Non-thermal radiation sources
• Line intensities
• Excitation rates
• De-excitation rates
• Electron impact ionization