Phase Screen Generation Methods for Simulating Light Propagation through non-Kolmogorov Turbulence

This paper is a continuation of past work that explored the efficacy of using a scintillometer to measure non-Kolmogorov turbulence. The goal here is to explore methods of phase screen generation to improve the computational efficiency, accuracy, and versatility of wave-optics simulations that represent high-fidelity measurements of non-Kolmogorov turbulence. Specifically, a Fast Fourier Transform-based phase screen generator is compared to the NERFS-HIPS phase screen generator, which was used in past work to generate phase screens for simulating light propagation through turbulence. Phase screens generated with the new method are then used to further explore whether a scintillometer provides a useful measurement of non-Kolmogorov turbulence across various atmospheric turbulence layers. It is found that the Fast Fourier Transform-based phase screens are of comparable accuracy to the NERFS-HIPS phase screens, and that the overall efficacy of the Fast Fourier Transform-based phase screens is high over a variety of atmospheric turbulence layers. Further, the new method can produce phase screens for all available turbulence layers, allowing a broader exploration of the turbulence effects compared with previous work. With turbulence simulated by these new phase screens, it is found that a scintillometer often overestimates the effects of this particular set of non-Kolmogorov turbulence. Such overestimates happen when the slope of the structure function is less than that of Kolmogorov turbulence over spatial separations smaller than the aperture diameter. This finding is consistent with past results.