High-frequency propagators for diffraction and backscattering in random media

This paper presents that scattering by a body in a random medium consists of the following two issues; one is scattering of spatially partially coherent wave by the body and the other is coupling between incident and scattered waves through the random medium. Investigating separately each issue makes the scattering more understandable. The numerical analysis of scattered power by conducting cylinders leads to the radar cross-sections quite different from those in free space, under the condition that the radar cross-section of the random medium is negligibly small. The causes of the difference are explained on the basis of above separation of the scattering, and we emphasize that the spatial coherence length of incident wave is one of key parameters for estimating the cross sections.

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“…The m s includes multiple-scattering effects of the random medium and can be obtained by two-scale method (13) (20) (21) (29) . It is given by…”

Section: Formulationmentioning

confidence: 99%

Scattering by Conducting Bodies in Random Media

2004

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“…Here the Fourier transformation is performed simultaneously with respect to the coordinates of the observation point (expansion in "incoming" plane waves) and with respect to the coordinates of the radiation point (expansion in "outgoing" plane waves). However, as shown by Tinin [1998] [Mazar, 1990]. As compared with the two-scale method dealing with the two-point propagator [Mazar, 1990] passed through a randomly inhomogeneous medium.…”

Section: Introductionmentioning

confidence: 99%

“…However, as shown by Tinin [1998] [Mazar, 1990]. As compared with the two-scale method dealing with the two-point propagator [Mazar, 1990] passed through a randomly inhomogeneous medium. Finally, in section 6, the applicability of the method to the problem of retrieving regular and nonregular structure of inhomogeneous ionosphere is analyzed.…”

Section: Introductionmentioning

confidence: 99%

Representation of a wave field in a randomly inhomogeneous medium in the form of the double‐weighted Fourier transform

Kravtsov¹,

Tinin²

2000

Radio Science

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Abstract. New integral representation of a wave field ,in a continuously inhomogeneous random medium is suggested in the form of double-weighted Fourier transformation, performed simultaneously with respect to coordinates of the source and the observer. The integral representation under consideration takes into account both the diffraction effects and the multiray effects. It incorporates many results of known techniques of wave propagation description in continuously inhomogeneous media: the methods of geometrical optics, smooth perturbations, phase screen, and two-scale expansions. The method delivers new opportunities to retrieve small-scale inhomogeneous structure of ionosphere plasma from radio-sounding data and can serve as the basis for diffraction tomography of the ionosphere.

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“…Combinations of the Maslov and interference integral methods were used in solving equations for the two-point random function (averaging of which gives the coherence function) [23] and Markov equations for statistical moments [24]. The same approach enabled solving the equation for the product of the desired field and the known solution (termed as "joker wave" in [25]) in extended 3D space for 2D problem [26] and in the extended 5D space for 3D problem [26][27][28][29].…”

Section: Advances In Mathematical Physicsmentioning

confidence: 99%

Higher Approximations to Study Statistical Characteristics of Waves in Multiscale Inhomogeneous Media

Tinin

2018

Advances in Mathematical Physics

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The previously obtained integral field representation in the form of double weighted Fourier transform (DWFT) describes effects of inhomogeneities with different scales. The first DWFT approximation describing the first-order effects does not account for incident wave distortions. However, in inhomogeneous media the multiscale second-order effects can also take place when largescale inhomogeneities distort the field structure of the wave incident on small-scale inhomogeneities. The paper presents the results of the use of DWFT to derive formulas for wave statistical moments with respect to the first-and second-order effects. It is shown that, for narrow-band signals, the second-order effects do not have a significant influence on the frequency correlation. We can neglect the contribution of the second-order effects to the spatial intensity correlation when thickness of the inhomogeneous layer is small, but these effects become noticeable as the layer thickness increases. Accounting for the second-order effects enabled us to get a spatial intensity correlation function, which at large distances goes to the results obtained earlier by the path integral method. This proves that the incident wave distortion effects act on the intensity fluctuations of a wave propagating in a multiscale randomly inhomogeneous medium.

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High-frequency propagators for diffraction and backscattering in random media

Cited by 35 publications

References 24 publications

Scattering by Conducting Bodies in Random Media

Scattering by Conducting Bodies in Random Media

Representation of a wave field in a randomly inhomogeneous medium in the form of the double‐weighted Fourier transform

Higher Approximations to Study Statistical Characteristics of Waves in Multiscale Inhomogeneous Media

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