Excitation and ionization of atoms and ions in a non-thermal plasma. I. Populations of excited levels

The author presents formulae for the populations of levels of excited atoms and ions of a plasma in non-thermal equilibrium over a wide range of electron densities. The validity of the method presented is established by comparison of the calculated population of excited levels of hydrogen-like ions with the results of McWhirter and Hearn (1963). For illustration, the population of excited levels of C II ions are calculated. On the basis of this method the partition function for hydrogen-like ions in a non-thermal plasma was obtained.