The intensity fluctuations of a wave beyond a random phase screen

Let us consider intensity fluctuations of a wave that is passed through a random phase screen. For a Gaussian s t ructura l function of the phase fluctuations in the plane of the screen an increase in the dispers ion of the intensity fluctuations is noted in the focusing regions (i.e., at distances z ~ Rph, where Rph is the charac te r i s t ic radius of curvature of the phase front of the wave behind the screen). It is shown that the stat ist ical proper t ies of the field depend essential ly on the fo rm of the s t ructura l function of the phase fluctuations.