A new target configuration producing an effective population inversion at energy levels of Mg XI 1s3p and 1s4p

Abstract

A microtube target with lateral jet nozzle has recently been developed. Strong population inversion was observed along the whole jet nozzle between the energy level of MgXI 1s3p 1P o 0 and that of 1s4p 1P o 0, while the average laser irradiance was around 3.5×10 13 W cm -2 on the inner wall of the microtube targets. A corresponding average electron temperature of 470–520 eV and density of 2×10 20 cm -3 at the inversion area of the plasma medium was measured. Possible mechanisms of the population inversion under the average high temperature condition have been analysed.