Possibilities of amplification of ultraviolet and soft X-ray radiation on multiply charged ion transitions in a recombining plasma

This paper is devoted to the analysis of the feasbility of stimulated emission on multiply charged ion transitions in a recombination-nonequilibrium plasma. The consideration is based upon the scheme of occurrence of inverted population, according to which the upper active level is pumped by a recombination flux and the lower active level is depopulated due to spontaneous radiative transitions. Results of numerical calculations of the gain and of the active ion recombination time as a function of electron temperature and concentration are presented. A review is given of the experimental observations of inversion on multiply charged ion transitions in a freely expanding laser plasma. The possibility of achieving appreciable gains in a plasma produced by a high-power flux of energetic particles (electrons, protons, photons) is considered.