The Wave Structure Function In Weak To Strong Fluctuations: An Analytic Model Based On Heuristic Theory

The Rytov perturbation method used to obtain the wave structure function in different fluctuation regimes, derived from analytic expressions governing statistical quantities, was described. The underlying physical theory explained that as the wave propagates, the intermediate refractive index scale sizes fail to refract or diffract the beam. A filter function was applied to the atmospheric spectrum and analytic expressions for the wave structure function for plane, spherical and Gaussian beam waves were developed using the Rytov perturbation method. It was also observed that the scintillation index, defined as the irradiance variance normalized by the square of the mean irradiance, increased with increasing values of Rytov variance