This work is concerned with the estimation of the bottom backscattering coefficient as a function of frequency and of incident angle. Generally, the backscattering coefficient is studied for a given frequency at various angle. But the backscattering depends not only on the angle, but also on the frequency. In our work, a wideband chirp sonar (20140kHz) with -3dB half-angle 12o has been used to ...

As the sand grain size approaches the acoustic wavelength, the underwater backscattering strength increases. Laboratory measurements show that the shallow-grazing angle backscattering strength increases as the third power of the normalized grain diameter, until it reaches a saturation level. In this regime, it has been shown that the attenuation of the sound in the sand increases as the fourth ...

This article investigates the interaction of a spherically symmetric massless scalar eld with a strong gravitational eld. It focuses on the propagation of waves in regions outside any horizons. The two factors acting on the waves can be identiied as a redshift and a backscattering. The innuence of backscattering on the intensity of the outgoing radiation is studied and rigorous quantitative upp...

We study coherent backscattering of a monochromatic laser by a dilute gas of cold two-level atoms in the weakly nonlinear regime. The nonlinear response of the atoms results in a modification of both the average field propagation (nonlinear refractive index) and the scattering events. Using a perturbative approach, the nonlinear effects arise from inelastic two-photon scattering processes. We p...

the use of acoustic waves in researches related to sea water is of most importance among scientistsrecently. since these waves are the only waves, transmitted in water with lowest attenuation and high speed, they canbe used in many scientific fields. the main goal of this research is to better understand the physics and mechanismsof sound-seabed interaction, including acoustic penetration, prop...

We investigated 2k-grating-assisted self-pumped phase conjugation in photorefractive Ce:BaTiO3 crystals. The phase-conjugation process involves a combination of four-wave mixing and stimulated photorefractive backscattering. An approximation involving separate interaction regions is used to theoretically calculate the reflectivity of phase conjugation as a function of the coupling strength of f...

Elastic backscattering of electrons moving along the helical edge is prohibited by time-reversal symmetry. We demonstrate, however, that an ensemble of magnetic impurities may cause time-reversal symmetry-preserving quasielastic backscattering, resulting in interference effects in the conductance. The characteristic energy transferred in a backscattering event is suppressed due to the Ruderman-...

The paper presents a description of new Ion Backscattering Beam Line. Small-size electrostatic accelerator “Sokol” with a beam energy range of 0.2...2.0 MeV is used as an ion source. A detail of the Beam Line is using of magnetic spectrometer which allows to carry out precise (several nm) quantitative layer-by-layer non-destructive element analysis of solid composition and structure using Ion E...

This article investigates the interaction of a spherically symmetric massless scalar field with a strong gravitational field. It focuses on the propagation of waves in regions outside any horizons. The two factors acting on the waves can be identified as a redshift and a backscattering. The influence of backscattering on the intensity of the outgoing radiation is studied and rigorous quantitati...

A method for directly simulating coherent backscattering of polarized light by a turbid medium has been developed based on the Electric field Monte Carlo (EMC) method. Electric fields of light traveling in a pair of time-reversed paths are added coherently to simulate their interference. An efficient approach for computing the electric field of light traveling along a time-reversed path is deri...