Deep turbulence propagation of a Gaussian-beam wave in anisotropic non-Kolmogorov turbulence

Abstract

In the conventional Kolmogorov model of turbulence the turbulent fluctuations of the index of refraction are assumed to be statistically homogeneous and isotropic, and there is a specific mathematical form for the power spectral density of the index of refraction fluctuations. Development of the turbulent theory of passive scalar transfer has shown that although the conventional Kolmogorov spectrum model with a 11/3 power-law index is generally correct near the ground (within the inertial subrange), it constitutes only one part of the more general behavior of passive scalar transfer in a turbulent flow. Hence, deviations from the conventional Kolmogorov model are possible. In this study we develop theoretical models for beam spot size, spatial coherence, and scintillation index that are valid in weak irradiance fluctuation regimes as well as in deep turbulence, or strong irradiance fluctuation regimes. These theoretical models are based on power-law index variations 3 <α< 4 in the spatial power spectrum model of atmospheric turbulence in addition to anisotropic conditions.