Experimental investigation of the physical processes applicable to amagnetohydrodynamic laser

Abstract

With a CO 2 probe laser the optimum small signal gain of magnetohydrodynamic (MHD) laser plasmas (typically 50 Torr, 1% CO2, 0.001% Cs in He) has been found from an extensive parametric study to be 0.32% cm. In the afterglow of the pulsed discharge, the relaxation rate of CO2 (10°0) by C02-CO2 collisions was 3.3 x 10 atms~, suggesting weak coupling between CO2 (010) and CO2 (10°0). The Cs-CO2 reaction was so slow that in a typical cavity only 0.5% Cs would be lost. Quenching of Cs excitation by CO2 is also negligible for MHD laser time scales. It is concluded that an MHD laser can provide higher specific power than either gasdynamic or electric discharge lasers, at thermal to optical conversion efficiencies of 2-3%.