EFFECT OF KINETICS OF MOLECULAR ABSORPTION OF RADIATION ON THE PROPAGATION OF A PULSE WITH lambda equals 10. 6 mu m IN THE ATMOSPHERE.

Much attention has been given to the problem of propagation of wave packets in the atmosphere, which is related to the important use of optical systems for the transfer of energy and information. The transmission of intense radiation through the atmosphere is associated with many nonlinear effects, which, for radiation at a wavelength of lambda equals 10. 6 mu m, include thermal self-action in the presence of the resonance absorption component of carbon dioxide. The author considers nonsteady-state thermal self-action of a collimated Gaussian beam of radiation with a wavelength of 10. 6 mu m transmitted through standard atmosphere, which does not contain dust particles or aerosols, along a beam path up to a height of 20 km above the ocean taking into account resonance absorption of radiation by atmospheric carbon dioxide. The effect of kinetic cooling and optical bightening of the medium on the form of the beam for different values of the radiation intensity and atmospheric humidity is analyzed. The pulse duration of a rectangular pulse is determined at the moment the beam becomes defocused, where the beam changes over a range from 0. 1 to 2 msec.