ANALYTIC EXPRESSIONS FOR THE WAVE STRUCTURE-FUNCTION BASED ON A BUMP SPECTRAL MODEL FOR REFRACTIVE-INDEX FLUCTUATIONS

A recently developed analytical spectral model for refractive index fluctuations, showing the characteristic 'bump' at high wave-numbers, is used to derive new expressions for the wave structure function associated with the propagation of infinite plane waves and spherical waves through isotropic and homogeneous turbulence. For computational ease, simple interpolation formulae are also developed for the wave structure function based on this new spectral model as well as on the more familiar modified von Karman spectrum. These interpolation formulae permit accurate numerical estimates for the wave structure function at all transverse separation distances up to the outer scale. Results based on the new bump spectrum are in excellent agreement with numerical values generated by the Hill spectrum.