Closed-cycle gasdynamic $CO_2$ laser employing a gas separator

A closed-cycle gasdynamic $CO_2$ laser is proposed which employs selective heating of the nitrogen, a supersonic mixer, a heat exchanger, and a gas separating device of the membrane type. Calculations are reported for a cascade of membrane-type elements to separate the gases, providing for cw operation of the gasdynamic laser under specified conditions. Estimates of the efficiency of a laser system of this type give $\eta=5,4$% for lasing in the $10,6\mu m$ band and $\eta=0,6$% in the $16\mu m$ band.