Vol. 6, issue 11, article # 1

Abstract:

In this paper we analyze some results of recent investigations of theoretical models and experimental data on the probability density of the intensity and flux fluctuations of optical radiation in the turbulent atmosphere. In doing so we consider the K—, universal, Beckman, and I—K distributions. We also analyze the errors in determining the highest normalized moments of the distributions and the influence of the instrumental dynamic range on the estimate of the probability density of fluctuations. As our comparative analysis of experimental data and model distributions has shown, the K—distribution is asymptotically more adequate for saturated fluctuations (b₀≥10) than the lognormal distribution and in addition approximates well the experimental data in the case of reflection of radiation from an array of corner—cube reflectors during propagation of radiation in the rain at large optical thicknesses. The fluctuations of the light flux reflected from specular objects and received by a distributed aperture practically always obey the lognormal law.
Experimental studies allow us to conclude that for arbitrary values of the parameter b₀, characterizing the conditions of light propagation, superposition of fields whose amplitudes obey the K— and lognormal distributions, is preferable for the description of experimental data.