Determination of relaxation time during the kinetic cooling of a moving gas

The paper examines the possibility of determining the vibrational relaxation time for V-T and V-V-prime processes in the case of the absorption by a moving gas of laser radiation whose frequency is resonant with respect to the frequency of the absorbing transition of the gas-mixture molecules. Results presented for an N2O-N2 mixture indicate that the character of the change of the macroscopic parameters of the moving gas in the resonant-radiation absorption region depends significantly on the magnitude of V-T and V-V-prime processes. This makes it possible to determine the characteristic times of such processes from experimental measurements of pressure, velocity, or temperature profiles in the absorption region.