Generating conditions of a laser-sustained argon plasma jet

Abstract

An argon plasma jet is produced from a continuous optical discharge at gas pressures in the range 2<or=P0<or=8 bar and effective laser power in the range 165<or=P<or=360 W. Plasma production is characterized by measurement of the threshold of the stability region (in terms of laser power-gas pressure). Study of the threshold law given by a simple model allows the core temperature of the plasma to be deduced. Temperatures are also measured by time-of-flight analysis of the neutral beam extracted from the plasma jet. They are compared with averaged temperatures deduced from the nozzle flow rate. From this comparison, a temperature profile over the nozzle radius can be calculated as can the heat flux through the nozzle. The kinetic energy yield of the continuous optical discharge can then be estimated. Values as high as 60% of the input laser power are obtained.