ANGULAR-DISTRIBUTIONS OF MULTIPLY SCATTERED LASER-RADIATION IN WEAKLYABSORBING MEDIA WITH LARGE-SCALE SCATTERING CENTERS

Dependence of the angular distribution of laser radiation on the regim e of single scattering is analyzed in a standard small-angle approxima tion. The contributions of scattering amplitudes of various multiplici ties to the formation of the radiation angular spectrum is considered. It is shown that the number of scattering events contributing to the radiation spectrum is considerably larger than the mean number of coll isions in the scattering layer. The radiation angular spectrum behavio r at relatively large depths is analyzed. In this case, the diffusion or quasi-diffusion approximation in angular space is shown to be valid , depending on the rate of the phase function decrease with the increa se of the single-scattering angle. For the phase functions decreasing with the increase of the scattering angle according to the power law, the radiation angular spectrum is shown to decrease according to the s ame law as the phase function at relatively large scattering angles. T he results of calculations are presented graphically for various model phase functions.