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《Waves in Random and Complex Media》2013,23(4):645-656
We suggest using spatial processing of the wave field with the aid of the double (in source and observer coordinates) weighted Fourier transform (DWFT) to suppress amplitude fluctuations (amplitude scintillations) during wave propagation in a randomly inhomogeneous medium. We examine the influence of sizes of receiving and transmitting antenna systems on the efficiency of the spatial processing in suppressing scintillations for both weak and strong intensity fluctuations. We demonstrate that the efficiency of the suppression of amplitude fluctuations by the inverse DWFT depends on the excess of sizes of fan beam projections of receiving and transmitting antenna systems over the Fresnel radius in a region with irregularities. 相似文献
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The intensity and the time correlation function of radiation transmitted through a layer of a randomly inhomogeneous medium are determined by numerical simulation of the Bethe-Salpeter equation for scalar and electromagnetic fields. The results of simulation agree well with the available experimental data. The domain of validity is determined numerically for the hypothesis of the diffusion approximation on the replacement of the extinction length by the transport length as a characteristic spatial scale for systems with the anisotropic scattering cross section. The polarized and depolarized components of the time correlation function of the transmitted light are calculated for the first time for different anisotropy parameters. It is shown that, to describe the residual polarization of transmitted light taking into account anisotropy, it is insufficient to perform the scale replacement of the extinction length by the transport length. 相似文献
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Zh. S. Gevorkyan 《Radiophysics and Quantum Electronics》1993,36(1):33-40
A theory of the radiation emitted by a charged particle moving in a randomly inhomogeneous correlated medium is constructed. It is shown that the radiation is isotropic and unpolarized. The frequency dependence of the radiation intensity is investigated and a peak is predicted in the wavelength region of e2a (where e2 is the dielectricconstant fluctuation and a is the correlation radius of the random field).Institute of Radio Physics and Electronics, Academy of Sciences of Armenia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 36, No. 1, pp. 51–64, January, 1993. 相似文献
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A theory of permittivity of suspension-type systems is developed that allows one to calculate such optical parameters of inhomogeneous systems as the length of scattering and the transport length. It is shown that, in the Born approximation, which takes into account two-particle correlations in the arrangement of scattering particles, the theoretical and experimental data are in agreement only to within tens of percent. The contribution of three-particle correlations to the permittivity of a system of solid spheres is determined. It is shown that, in describing the optical properties of suspensions with a large difference between the refractive indices of the medium and the particles, it does not suffice to replace the Rayleigh-Gans form factor by the Mie form factor, even under a restriction to two-particle correlations. 相似文献
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A. A. Stanislavsky 《Journal of Experimental and Theoretical Physics》2004,98(4):705-706
An integrodifferential equation describing the angular distribution of beams is analyzed for a medium with random inhomogeneities. Beams are trapped because inhomogeneities give rise to wave localization at random locations and random times. The expressions obtained for the mean square deviation from the initial direction of beam propagation generalize the “3/2 law.” 相似文献
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Using the method of refractive scattering of radio waves (RSRW), we solve the problem of space correlation of scintillations
of radiation from an extended source in a randomly inhomogeneous medium. General expressions are obtained for the index and
radius of the space correlation of fluctuations of intensity of radiation from a source with finite angular dimensions as
it propagates though a multilayered medium with refractive index fluctuations. The RSRW method is similar to the diffraction
calculation of space correlation of scintillations of an extended source in a thick layer with inhomogeneities. We note that
under certain conditions an increase in the number of inhomogeneous layers on the radio wave propagation path leads to a pronounced
decrease in the scintillation index and an increase in the space correlation of fluctuations of intensity of received radiation
from an extended source. The results obtained have a simple geometric-optical interpretation. We indicate a specific feature
in determining the angular dimensions of extended radio sources using the known method of scintillations.
Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika,
Vol. 40, No. 5, pp. 586–593, May, 1997. 相似文献
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Pacific Oceanological Institute, Far East Division, Academy of Sciences of the USSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 33, No. 11, pp. 1232–1236, November 1990. 相似文献
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Broadening of a laser beam in a turbulent medium 总被引:3,自引:0,他引:3