Atmospheric spectral model and theoretical expressions of irradiance scintillation index for optical wave propagating through moderate-to-strong non-Kolmogorov turbulence

Abstract

A new atmospheric spectral model and expressions of irradiance scintillation index are derived theoretically for optical wave propagating through moderate-to-strong non-Kolmogorov turbulence. They are developed under Andrews' assumption that small-scale irradiance fluctuations are modulated by large-scale irradiance fluctuations of the wave, and the geometrical optics approximation is adopted for mathematical development. A wide range of turbulence strength is considered instead of a limited range for weak turbulence. The atmospheric spectral model has a spectral power law value in the range of 3 to 4 instead of the standard power law value of 11/3. Numerical calculations are conducted to analyze the influences of spectral power law and turbulence strength.

Influence of moderate-to-strong non-Kolmogorov turbulence on the imaging system by atmospheric turbulence MTF

“…The effective non-Kolmogorov turbulence spectrum for moderate-to-strong non-Kolmogorov turbulence takes the form as [14] n1 (Ä, ˛) = ˚n (Ä, ˛) G (Ä, ˛) ,…”

“…That is, the small-scale (Ä > Ä Y (˛)) and large-scale (Ä < Ä X (˛)) turbulence eddies' effects are significant in the analysis of optical waves propagating through moderate-to-strong non-Kolmogorov turbulence, and the intermediate-scale (Ä X (˛) < Ä < Ä Y (˛)) turbulence eddies' effects can be neglected. The expressions of Ä X (˛) and Ä Y (˛) have been derived in [14] for plane and spherical waves propagating through moderate-to-strong non-Kolmogorov turbulence and exhibited in Appendix A of this paper.…”

“…When turbulence strength continues to increase up to moderate-to-strong (or strong) regime, these models are not applicable. Recently, the effective non-Kolmogorov turbulence spectral model [14] has been proposed for the theoretical investigation of optical waves propagating through moderate-to-strong (or strong) non-Kolmogorov turbulence, and has been used to analyze the irradiance scintillation and angle of arrival fluctuations [14][15][16].…”

“…In this study, based on the extended Rytov theory, the effective non-Kolmogorov spectral model [14] is assumed to be valid to theoretically investigate the atmospheric turbulence MTF for both plane and spherical waves propagating through moderate-to-strong non-Kolmogorov turbulence. First, the theoretical expressions of wave structure function for plane and spherical waves are derived.…”

Experimental observation of spatial correlation of scintillations from an extended incoherent source

“…The weak nonKolmogorov turbulence spectrum is given by Cui et al 10 as where the Kolmogorov spectrum is a special case given by α ¼ 11∕3, and the parameter κ is the spatial wavenumber. In the analyses below, the spectral power law parameter α has been varied around 11∕3, fitting the experimentally observed cross-correlation.…”