Thermal blooming of a laser pulse in the atmosphere

Numerical-modeling results are given concerning the propagating of a pulsed Gaussian beam at a wavelength of 10.6 microns in the lower atmosphere at heights up to 3 km. It is shown that the atmosphere can produce the significant thermal blooming (TB) of laser pulses, which increases in summer and in the case of the transition from vertical paths to oblique ones. Numerical results point to the necessity of taking into account the magnitude of TB in determining the parameters of a beam that assure its passage through a layer of water aerosol. It is noted that the thermal self-defocusing of pulsed beams can be reduced by reducing the pulse duration.