Emission Spectrum of Helium-Like Ions in Photoionized Plasmas

The aim of the present paper is to investigate the influence of inner-shell photoionization and photoexcitation on He α and its satellite's spectra in photoionized plasmas. An analysis is carried out on the relative importance of the various atomic processes in photoionized plasmas as a function of the electron temperature and irradiation conditions. In particular, we investigate the influence of K -shell photoionization of Li-like ions on the He α spectrum and of Be-like ions on the He α satellites. It is found that in photoionized plasmas these inner-shell processes contribute significantly under low radiation temperature and/or intensity, when Li- and Be-like ions are highly abundant but highly ionized H-like ions are rare. A short discussion is presented about the parameter space in which the excited 1 s 2 p state has statistical or non-statistical distributions, and how such distributions affect the emission spectrum.