Theory of optical scintillation: Gaussian-beam wave model

    Authors

    L. C. Andrews; M. A. Al-Habash; C. Y. Hopen;R. L. Phillips

    Abbreviated Journal Title

    Waves Random Media

    Keywords

    IRRADIANCE-VARIANCE; INNER-SCALE; SPATIAL COHERENCE; SPECTRAL MODEL; FLUCTUATIONS; TURBULENCE; PROPAGATION; ATMOSPHERE; WEAK; Physics, Multidisciplinary

    Abstract

    A scintillation model previously developed by the authors is extended in this paper to the case of a propagating Gaussian-beam wave. As in the previous model, we account for the loss of spatial coherence as the optical wave propagates through atmospheric turbulence by eliminating effects of certain turbulent scale sizes that exist between the scale size of the spatial coherence radius of the beam and that of the scattering disc. These mid-range scale-size effects are eliminated through the formal introduction of spatial frequency filters that continually adjust spatial cut-off frequencies as the optical wave propagates. Unlike the previous model, in this paper we include the effect of a finite outer scale in addition to the inner scale. With a finite outer scale, the scintillation index can be substantially lower in strong turbulence than that predicted by a model with an infinite outer scale. This particular behaviour of scintillation in strong turbulence, mostly associated with horizontal paths near the ground, cannot be explained on the basis of previous expressions deduced from the asymptotic theory. Comparisons of the scintillation models with published experimental and simulation data through weak and strong irradiance fluctuations show excellent fits.

    Journal Title

    Waves in Random Media

    Volume

    11

    Issue/Number

    3

    Publication Date

    1-1-2001

    Document Type

    Article

    Language

    English

    First Page

    271

    Last Page

    291

    WOS Identifier

    WOS:000170142300007

    ISSN

    0959-7174

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