A pseudo-state sensitivity study on hydrogenic ions

Abstract

An electron-impact excitation study of light hydrogenic ions has been carried outto quantify the effects of coupling to high bound/continuum states utilizing theR-matrixwith pseudo-states method. As the ionization stage increases, the neglect of loss offlux into high-lying excitation/ionization channels impacts less upon excitationbetween the bound terms explicitly included within our close coupling expansion.C5+is used as our benchmark study. The differences in Maxwell averaged collision strengths betweena standard R-matrixcalculation and those of a similar pseudo-state model across a range oftemperatures shall be our criteria for judging differences.We carried out calculations for He+, Li2+, Be3+, B4+, C5+, O7+ andNe9+so as to provide excitation data amongst terms up ton = 5.Pseudo-state calculations were carried out for the first five ions, following a similarmodel to earlier neutral hydrogen work, whilst non-pseudo-state calculationssufficed for the remaining two ions. The results of these seven calculations willenhance existing excitation data sets for use in the modelling of controlled nuclearfusion plasma experiments.