Scintillation theory of optical waves propagating through moderate to strong compressible turbulence

Abstract

Compressible turbulence around an aircraft will cause irradiance fluctuations in the optical waves in optical communication between the aircraft and the outside. Turbulence can cause signal fluctuation or even interruption, and the exploration of the issue plays an important role in aero-optics. Based on the extended Rytov theory, we develop theoretical expressions of the scintillation index for plane and spherical waves propagating in moderate to strong compressible fluctuations by a near wall compressible turbulence refractive index spectrum. The numerical results show that the derived scintillation index is in good agreement with weak fluctuation and asymptotic theory approximation. The predicted scintillation index first increases sharply with the path length and reaches a peak, after which it falls back to saturation. During weak fluctuations, the scintillation index of long wavelength waves is smaller than that of short wavelength waves, but in moderate to strong turbulence, the scintillation index of short wavelength waves has an advantage over that of long wavelength waves. Furthermore, we provide physical explanations for the scintillation index trend.