Multiple foci in the range dependence of the intensity fluctuations of a plane wave propagating in a random medium.

The differential equation for the fourth-order statistical moment of the field of a plane wave propagating in a two dimensional random medium is solved numerically. Results are presented for the scintillation index when the index-of-refraction correlation function of the medium is Gaussian and gamma (ratio of diffraction length to scattering length) is 50. It is pointed out that the solution has multiple foci, and it is suggested that this characteristic will be more pronounced for larger values of gamma.