Parametrization of the scattering indicatrix for a finite scattering medium

We consider a method of parametrizing the radiative scattering indicatrix. The scattering indicatrix is represented as projections , , on the axes of a Cartesian system of coordinates. Examples are discussed of the experimental determination of these parameters for a model dispersive medium consisting of a solution of polystyrene latex particles in water.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 36–39, October, 1985.     

On the effect of the width of the scattering indicatrix on the dispersion of photon density waves in a strongly scattering medium

The dispersion of photon density waves in strongly scattering media with different widths of the scattering indicatrix is studied by the spherical harmonics method using approximations of various orders (up to the P ₇ approximation inclusive). It is shown that, beginning from the P ₃ approximation, the reduction in the velocity of photon density waves that is characteristic of the P ₁ approximation is eliminated and, independently of the width of the scattering indicatrix in the region of modulation frequencies exceeding 10¹⁰ Hz, the velocity of photon density waves asymptotically approaches the speed of light. Our study of the damping of photon density waves has shown that the formula obtained previously for the calculation of the damping coefficient (Imk(μ _s ^′ , ω)) as a function of the transport scattering coefficient and the velocity is valid at Imk ≤ μ_s (μ_s is the light scattering coefficient). The maximum growth in the damping coefficient of photon density waves with a further increase in the frequency is limited by the value of the light scattering coefficient Imk _max ≈ μ_s.     

Diffusive propagation of radiation in an absorbing dispersion medium with highly elongated scattering indicatrix in the case of an obliquely incident broad beam

Engineering Physics Institute, Moscow. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 33, No. 2, pp. 202–212, February, 1990.     

Charge asymmetry and neutron-neutron scattering

The uncertainty in the subtraction of electromagnetic effects from S-wave proton-proton scattering potentials is studied in two models using unitarily transformed potentials. Restrictions on these models caused by theoretical, off-shell and deuteron constraints are imposed. The probable uncertainty of physical interest is found to be small. It is typically only a few parts per thousand of the one-pion exchange potential. It has relatively little effect on Coulomb displacement energies. Phenomenological charge-symmetry-breaking potentials are constructed which both fit the experimental neutron-neutron (nn) scattering length (?16.4 fm). and give roughly the needed Coulomb displacement energies. These phenomenological potentials are found to contain a short-range repulsion and a strong long-range attraction for a neutron pair. The need for experimental information on the shape and state dependence of the nn force is emphasized. These can probably be obtained from precise nn scattering measurements.     

Experimental method to detect chiral asymmetry in specular light scattering from a naturally optically active medium

An experimental method is described for measuring chiral asymmetries in specular light scattering from a naturally optically active medium with a sensitivity on the order of one part in 10⁶. The chiral asymmetries of interest are the differential reflection of left and right circularly polarised light (circular differential reflection) and the deviation from mutual orthogonality of reflected transverse electric and transverse magnetic polarised light (skewness). The measurement of these chiral asymmetries would permit one to test the recently predicted Fresnel amplitudes for reflection from isotropic optically active transparent and absorving media and thereby to resolved controversial fundamental issues concerning the electrodynamics of chiral media.     

Left-right asymmetry in Compton scattering on polarized electrons

In Compton scattering on polarized electrons a left-right asymmetry of the order 10⁻³ has been observed which must be attributed to higher-order corrections of the scattering amplitude. This effect might provide a test of quantum electrodynamics.     

Optical fiber diameter measurement by the diffraction method with digital processing of the light scattering indicatrix

Relations between the position of the first diffraction minima and the fiber diameter are derived based on the solution of the problem of electromagnetic wave diffraction on a transparent fiber with a circular cross section. The obtained formulas are used to measure the fiber diameter. The diffraction pattern is recorded with a digital camera. The obtained image is digitally processed to determine the positions of the first two scattering indicatrix minima.     

Calculation of the scattering indicatrix of systems of spheres based on the dimensionless formulation of the solution of the mie problem

Dimensionless formulas describing the field scattered by a single sphere are used to derive the scattering indicatrix of systems of spherical particles whose size parameter is less than unity. These formulas can greatly expedite the calculations when the required precision of the results is a few percent.     

Effect of turning of rays on scattering of light in a layered medium

The problem of the scattering of light by random inhomogeneities in a layered medium whose characteristic scale is large compared to the wavelength of light is considered. The attention is mainly focused on the effect that the turning of incident and scattered waves has on light scattering in such a medium. In the mixed (q _⊥, z) Fourier representation, expressions for normal waves, and Green’s function are found, which can be used both far from the turning point, where the fields are described in the WKB approximation, and near this point, where the fields are described using the Airy function. Based on these expressions and using the Kirchhoff method, a general expression for the scattering intensity in the far field of the sample is obtained, which takes into account the turning of the incident and scattered waves in the fluctuating medium. Physical consequences of the calculation results are analyzed. In particular, it is shown that even a comparatively small gradient of the refractive index in the layer leads to a rather appreciable redistribution of the scattering intensity between the forward and backward hemispheres. In this case, the shape of the scattering indicatrix is rather exotic with sharp discontinuities, peaks, and dips whose amplitude is on the order of the intensity itself. Original Russian Text ? A.Yu. Val’kov, A.A. Zhukov, V.P. Romanov, 2008, published in Optika i Spektroskopiya, 2008, Vol. 105, No. 4, pp. 647–666.     

Effect of asymmetry of CuO2 layers in copper oxides on the anomalous neutron scattering near T c

Reasons for critical magnetic scattering of neutrons near T _c in copper oxides with CuO₂ layers whose nearest environment has no “up-down” symmetry are discussed. The intracrystalline electric field, which threads the CuO₂ planes on account of the asymmetry, induces coupling between the spin and momentum of the current carriers. This coupling is shown to result in a manifestation of virtual Cooper pairs in the imaginary part of the spin susceptibility. Thus spin density fluctuations as well as current fluctuations should participate in the scattering. A way of experimentally distinguishing between the two mechanisms is pointed out. Pis’ma Zh. éksp. Teor. Fiz. 69, No. 5, 363–368 (10 March 1999) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Analysis of scattering medium structure from data on the multiple scattering of electromagnetic radiation

The radiation transfer equation for a semi -infinite scattering medium is solved. The solution provides information on the size distribution function of the scattering particles, starting from experimental data on the multiple scattering of electromagnetic radiation. A solution is obtained for the case where the probability of scattering is given by the solution of Mie's problem.