Enhancement of Effective Excitation Rate Coefficients of Ions in Dense Plasma through Doubly Excited States.

Abstract

We constructed a collisional-radiative model including doubly excited states for a two electron ion. We study the density effects on the effective rate coefficients and the n-dependence of the population densities where n is the principal quantum number. The effective 1s-2l excitation rate coefficients increase with increasing electron density due to the indirect process. We also found that for 2s-1s de-excitation,l-changing transitions, 2snl-2pnl, are important at intermediate densities. The population densities per statistical weight for doubly excited states attain a scale of n-4 at very high density in ionizing plasmas.