Laser propagation in the atmosphere

The problem is the variance and covariance of amplitude in a focused Gaussian laser beam propagating in a random medium with a von Karman turbulence spectrum. The Rytov method is employed, and a numerical program is used to calculate the effects of the beam parameters (aperture size, wavelength and focal length) and atmospheric turbulence parameters (structure constant, inner and outer scale of turbulence) upon the covariance function.