High-order satellites and plasma gradients effects on the ArHe beta line opacity and intensity distribution

We study the effects of high-order n = 4 Li-like satellites and plasma dens ity and temperature gradients on the Ar He beta line opacity and intensity distribution, using a spectroscopic-quality atomic kinetics and radiation t ransport model. The model self-consistently accounts for NLTE level populat ion kinetics, Stark broadened line shapes, and radiation transport effects, High-order satellites with a spectator electron in n = 4 make a significan t contribution to both opacity and line intensity distribution of the Ar He -beta composite line for plasma conditions typical of ICF imploded cores. W e also discuss the impact of plasma density and temperature gradients on th e formation of this spectral feature and show that the combined effect of g radients and opacity can lead to a characteristic round shape in the center of the He-beta line. (C) 2000 Elsevier Science Ltd. All rights reserved.