Investigation of the active medium of a gasdynamic laser with nitrogen heating in a finite-volume chamber

An investigation was made of a variant of a mixing gasdynamic laser with nitrogen heating by an electric discharge in a 0.7-liter chamber. The time dependences of the gain K₀(t) were determined for two rotational transitions in the 001–100 band of the CO₂ molecule. When nozzle arrays with mixing of fluxes in an expanding channel were used, the values of the gain were found to be K_0max^P(20) = 3.4 m^–1 and K_0max^P(16) = 4 m^–1 at nitrogen temperatures (in the heater) of 1500 and 1700 K, respectively. A vibrational nonequilibrium of nitrogen appeared in the high-pressure chamber and grew in the course of flow of nitrogen out of this chamber. In 13 msec from the beginning of flow the vibrational energy of the nitrogen molecules in this chamber exceeded the equilibrium value by a factor of 1.4.