Performance analysis of and compensation for aspect-ratio effects of fast-fourier-transform-based simulations of large atmospheric wave fronts.

Fast-Fourier-transform-based simulators of atmospheric wave fronts with a von Kármán turbulence spectrum were tested with reference to the phase-structure function and phase variance over a pupil on large square and rectangular formats. The symmetry and the accuracy of the phase-structure function were found to be limited by the aspect ratio and the size of the phase screen. The phase variance over a pupil is less sensitive to the aspect ratio than the phase-structure function and is dependent mainly on the size of the phase screen. Several tests are reported and discussed together with a method of compensation for the negative effects of rectangular formats.