Simplified modeling of atmospheric turbulence

Accurate simulation of a ground-based adaptive optics system requires a realistic model of atmospheric turbulence. Conventional models of atmospheric phase distortions involve two- dimensional Fourier transforms, and are thus complex and slow. In the Kolmogorov-Taylor `frozen' approximation, there is an alternative way to generate a phase screen directly that is a close approximation to the theoretical phase structure. We approximate the exact atmospheric transfer function in a stair-step fashion using only integral powers of spatial frequency. Then conventional digital filter synthesis techniques are used to produce the phase screen directly. Examples are shown for several different atmospheric power spectral density functions, and their statistics discussed.