Population kinetics of lithiumlike and berylliumlike ions in low temperature dense recombining plasma

A collisional-radiative model for the lithiumlike and berylliumlike ions has been constructed. In this model, virtually all the doubly excited levels of the berylliumlike ions are taken into account. Time-differential coupled rate equations for the level populations of the lithiumlike and berylliumlike ions are solved under a recombining plasma condition, and the population kinetics of these ions, especially for the validity of quasisteady state (QSS) approximation and the population flux into and out of excited levels, is discussed. Temporal evolution of gains of the 3d D-2-4f F-2 and 3d D-2-5f F-2 lines of the lithiumlike aluminum laser is also calculated, and the result indicates that the gain is generated before the establishment of the QSS condition.