Abstract

Experiments performed in recombinating aluminium plasmas have shown, for various conditions of plasma production, that population inversions occur between the levels 3, 4, 5 of lithium-like ions ^(1-4). In references 1 and 4, inversions between 3d and 4d or 5d levels have been deduced from the analysis of line intensity ratios corresponding to 2p-nd transitions. In references 2 and 3, the evidence of an inversion between the 3d and 5f levels resulted directly from the behaviour of the 3d-5f line for relevant changes in plasma geometry in the line of sight. Numerical modelling, in which rate equations are solved for 22 levels, has suggested that the explanation of these inversions refers to the recombination scheme (5).

© 1984 Optical Society of America