The effect of Lyman alpha self-absorption on population inversions between quantum states 2 and 3 of hydrogen-like ions in recombining plasmas

The effect in recombining plasmas of Lyman alpha self-absorption on quasi-steady-state population inversions between quantum states n=2 and 3 of hydrogen-like ions is theoretically investigated. It is shown how the electron density range over which population inversion is possible diminishes as Lyman alpha self-absorption increases. The highest degree of absorption which can be tolerated and still achieve an inversion is shown to occur when the thermal limit corresponds to n approximately=4. The results of the computations are related to the conditions to be found in the expansion plume of laser-produced plasmas.