The recombination and level populations of ions II. Resolution of angular momentum states

Abstract

Methods of analysis of the recombination and population structure ofions in a thermal plasma are extended to permit unification of theunresolved angular momentum quantum number treatment of highly excitedstates with a resolved angular momentum treatment of lower states.Hydrogen and helium are considered and best available rates forprocesses involving the lowest levels are incorporated. Generalizedcollisional radiative recombination and ionization coefficients arepresented and the effect of a strong Lyman alpha radiation field onhydrogen is investigated. The whole population structure of hydrogen andhelium for a representative selection of planetary nebular conditions ispresented.