Covariance of irradiance fluctuations propagating through a thin turbulent slab

Irradiance fluctuations of a plane wave propagating through a strongly refracting thin turbulent slab are treated. The parabolic wave equation of the fourth‐order moment of the field is solved by an operational method and the triple integral form of the solution is obtained. Numerical results of the variance function show the saturation effect and the values of the covariance are given for the under‐ and over‐saturation regions.