MODELING OF THE PARAMETRIC BEHAVIOR OF A SELF-HEATED COPPER-VAPOR LASER - ISSUES GOVERNING THE THERMAL RUNAWAY BEHAVIOR OF THE PLASMA TUBE WALL TEMPERATURE

A computer model has been used to simulate the discharge kinetics and parametric behaviour of a self-heated copper vapour laser for a wide r ange of optimum and non-optimum conditions. The results indicate that the ground state copper density and the peak electron temperature are the two most important parameters that affect laser performance. The r esults also confirm the existence of a threshold wall temperature (or threshold copper density) above which the plasma tube becomes thermall y unstable with respect to the deposited electrical power, the wall te mperature and the copper density, ultimately leading to thermal runawa y. At low pulse repetition frequency (prf<8kHz), the thermal instabili ty restricts the copper density (and laser output power) to values wel l below optimum.