The mean-square fluctuations of log amplitude and phase are analytically obtained for gaussian light-beam propagating through a randomly inhomogeneous medium with gaussian covariance of the refractive-index fluctuations. The beam used is radiated from an extended source with a circularly symmetric gaussian amplitude distribution and a curved wavefront (phase variation) which characterize the beam shape. The dependence of the fluctuation distribution upon the beam shape and the scale of the medium turbulence is discussed.
YASUAKI KINOSHITA, "Fluctuation Distribution of Gaussian Beam Propagating Through a Random Medium," J. Opt. Soc. Am. 58, 798-805 (1968)