Modeling of the turbulent phase in strong scintillation conditions

Abstract

Monte-Carlo models of the turbulent phase are widely used in the studies of the optical propagation through turbulence atmosphere. However all algorithms, that are currently in use, generate continuous smooth phase samples. Meanwhile, it is well-known that under strong scintillation conditions turbulent phase has singularities, and phase is discontinuous across the branch cuts connecting the singularities. Markov approximation for wave propagation through random inhomogeneous media 1, 2 predicts that under the strong scintillation conditions optical field asymptotically has normal distribution 3 . We propose to generate the phase samples under strong scintillation conditions by first producing a complex normal random field with a given coherence function, and then recovering the random phase as the argument of this field. This approach allows generation of the two-dimensional discontinuous random phase samples that include phase singularities. Phase simulation algorithm is based on the Sparse Spectrum concept that was introduced in our earlier works, and can be modified to fit any desired shape of the turbulence spectrum. We verify the accuracy of the phase samples statistics by comparison with the theoretical results presented in the companion paper.