Scattering of electromagnetic waves by three-dimensional arbitrary shaped magnetodielectric body

Using the method of discrete sources, we solve the problem of electromagnetic wave scattering by an arbitrarily shaped magnetodielectric body. The capabilities of the developed software are briefly described. We present some numerical results aimed at analyzing the influence of magnetic properties of absorbing scatterers and deviations of the scatterer shape from the axisymmetric one on the bistatic cross section. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 4, pp. 348–356, April 2006.     

Diffraction of electromagnetic waves in a three-dimensional magnetodielectric body of arbitrary shape

A numerical method of solving the problem of the diffraction of electromagnetic waves by a three-dimensional magnetodielectric body of arbitrary shape in the resonance frequency region is proposed. The method is applied in the form of a FORTRAN software package for calculating the components of the diffraction field of bodies with different electrodynamic and geometrical parameters. The directivity parameters of some bodies of complex shape are given.V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 87–91, June, 1995.     

Diffraction of electromagnetic waves by three-dimensional ideally conducting bodies in a magnetodielectric envelope

A numerical method of solving the problem of the diffraction of electromagnetic radiation by structures which are an ideally conducting body of arbitrary shape in a uniform magnetodielectric envelope is proposed. The method is implemented in the form of a program for calculating the components of the diffraction field of structures with different geometrical and electrodynamic parameters. Some results of numerical investigations, carried out to investigate the effect of deviations of the shape of the structure from axisymmetrical on the energy characteristics of the scattered field, are presented. V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 47–51, July, 1998.     

Light diffraction by a strong standing electromagnetic wave

The nonlinear quantum interaction of a linearly polarized x-ray probe beam with a focused intense standing laser wave is studied theoretically. Because of the tight focusing of the standing laser pulse, diffraction effects arise for the probe beam as opposed to the corresponding plane wave scenario. A quantitative estimate for realistic experimental conditions of the ellipticity and the rotation of the main polarization plane acquired by the x-ray probe after the interaction shows that the implementation of such vacuum effects is feasible with future X-ray Free Electron Laser light.     

Scattering of electromagnetic waves on a magnetodielectric with chiral properties

The numerical method that we proposed earlier for solving the problem of diffraction of electromagnetic waves on three-dimensional magnetodielectric bodies of any shape in the resonance frequency range is generalized to the case of objects having chiral properties. The results of numerical calculations of bistatic scattering cross sections of spherical and cylindrical chiral objects are reported. The influence of the values of the chirality parameters and of electrical and magnetic absorption on the scattering diagrams is examined. V. D. Kuznetsov Siberian Physicotechnical Institute at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 89–95, August, 1996.     

Scattering of a plane electromagnetic wave by an infinite wedge with a truncated circular cylinder coated coaxially with a magnetodielectric layer

We formulate and solve the problem of scattering of a plane electromagnetic wave by an infinite, perfectly conducting wedge with a truncated, perfectly conducting circular cylinder which is coated coaxially with a magnetodielectric layer and located along the wedge edge. The rigorous solution is obtained and reduced to a system of linear algebraic equations of the second kind for unknown coefficients of Fourier expansions of the scattered field. The results of calculating the scattered field in the far zone with a specified accuracy are presented for the case of an H-polarized wave. It is shown that for certain values of the electric radius of the cylinder, the backscattering cross section of such a structure has pronounced maxima.     

Optical forces from an evanescent wave on a magnetodielectric small particle

We report the first study on the optical force exerted by an evanescent wave on a small sphere with both electric and magnetic responses to the incident field, immersed in an arbitrary nondissipative medium. New expressions and effects from their gradient, radiation pressure, and curl components are obtained owing to the particle induced electric and magnetic dipoles, as well as to their mutual interaction. We predict possible dramatic changes in the force depending on the host medium, the polarization, and the nature of the surface wave.     

A theory of the diffraction of an electromagnetic wave by a plane screen

The problem of the diffraction of an arbitrarily polarized electromagnetic plane wave by a perfectly conducting plane screen of infinitesimal thickness is reduced to scalar problems by the method known from earlier papers. The wave field diffracted either by a screen of infinite extent which is perforated by an aperture of arbitrary size and shape or by a complementary screen is then described by means of the bra-vectors, ket-vectors and linear operators introduced by the present author in one of his preceding papers.     

Numerical analysis of propagation characteristics of electromagnetic wave in lossy left-handed material media

The propagation characteristics of electromagnetic wave in lossy left-handed materials (LHM) are studied using finite-difference time-domain (FDTD) method base on auxiliary differential equation (ADE) technology. The LHM medium is realized with lossy Drude models for both the negative electric permittivity and the negative magnetic permeability. The discretized ADE-FDTD equations are derived in detail. The incident wave used in the simulation is a multiple cycle m-n-m pulses source. The term of Poynting's vector E_xH_y was calculated. These numerical results demonstrate conclusively that the phase velocity direction of electromagnetic wave propagation and the direction of the Poynting vectors are anti-parallel in LHM. The amplitude of electric field is reduced with the enhancive distance of LHM slab. It is also demonstrated that the energy of electromagnetic wave in the LHM slab is obviously attenuated, and the attenuation of energy becomes stronger with the angular plasma frequency ω_p increasing. These results indicate that LHM stealth is effective in theory, and reasonable selection of the large negative index of refraction can greatly enhance its effectiveness.     

Numerical study of three-dimensional detonation wave dynamics in a circular tube

The three-dimensional structures of a detonation wave propagating in a circular tube were investigated using a one-step irreversible Arrhenius kinetics model. A series of parametric studies were carried out to investigate the different modes of cell structure formation by changing the pre-exponential factor. Maximum pressure trace was recorded along the tube wall to investigate the detonation cell structures. The unsteady results obtained in three dimensions revealed the generation mechanism of the wave front structures of two-, three- and four-cell mode detonations. A six-cell mode detonation could be obtained using a finer grid. With the increase in pre-exponential factor, it was found that the number of detonation cells is increased while the cell size is reduced accordingly. In all the multi-cell modes, the detonation wave structures and smoked-foil records on the wall are formed by the propagation of transverse waves along the wall in clockwise and counter-clockwise directions, while the slapping wave moves in the radial direction. The presence of the slapping wave further strengthens the wave interactions in three-dimensional simulation. Comparison with two-dimensional simulation confirms the effect of the slapping wave in the radial direction. As a result, the detonation wave front structures changes from the polygonal shape to the multi-bladed fan shape, periodically.     

Solution of the three-dimensional problem of plane wave diffraction by a two-period plane grating

Using the discrete source method, we develop an algorithm for solving the three-dimensional problem of wave scattering by a plane grating consisting of acoustically soft or acoustically stiff bodies. An efficient algorithm is proposed for determining the periodic Green’s function of the grating. Numerical results are obtained for different geometries of the grating elements. The fulfillment of the energy conservation law is verified along with the fulfillment of the boundary condition at the surface of the central grating element.     

球面电磁波斜入射建筑物内场的数值分析

为了分析窄带电磁脉冲源近、远场辐照大型建筑物内部空间电磁场分布特点,采用时域有限差分方法,对比分析平面波、球面波场源正面斜入射多层多单元建筑物的计算结果,并较为全面地分析了各房间各水平面中心电场强度幅值、各层各水平面电场强度最大值分布情况。建筑物各层相对应高度面上场强分布近似,在电磁波传播方向上窗户房间内部区域场强较强,两种波场源入射结果基本一致;在其余区域场强较弱,特别是在较大空间内的区域,球面波场源入射下场强相对更弱。其中通过与待模拟建筑物外形相紧凑性匹配的球面波场源构建,模拟仿真了窄带球面电磁波在真空空间的辐射传播,计算结果验证所构建球面波近场源准确可行。     

Modelling of electromagnetic wave interactions with the human body

Electromagnetic modelling plays a more and more important role in the study of complex systems involving Maxwell phenomena, such as the interactions of radiowaves with the human body. Simulation then becomes a credible means in decision making, related to the engineering of complex electromagnetic systems. To increase confidence in the models with respect to reality, validation and uncertainty estimation methods are needed. The different dimensions of model validation are illustrated through dosimetry, i.e., quantification of human exposure to electromagnetic waves. To cite this article: M.-F. Wong, J. Wiart, C. R. Physique 6 (2005).     

球面电磁波斜入射建筑物内场的数值分析

为了分析窄带电磁脉冲源近、远场辐照大型建筑物内部空间电磁场分布特点,采用时域有限差分方法,对比分析平面波、球面波场源正面斜入射多层多单元建筑物的计算结果,并较为全面地分析了各房间各水平面中心电场强度幅值、各层各水平面电场强度最大值分布情况。建筑物各层相对应高度面上场强分布近似,在电磁波传播方向上窗户房间内部区域场强较强,两种波场源入射结果基本一致;在其余区域场强较弱,特别是在较大空间内的区域,球面波场源入射下场强相对更弱。其中通过与待模拟建筑物外形相紧凑性匹配的球面波场源构建,模拟仿真了窄带球面电磁波在真空空间的辐射传播,计算结果验证所构建球面波近场源准确可行。     

Numerical analysis of effects of thickness on electromagnetic wave absorption properties of CPCCB/paraffin wax composite

Using a refection/transmission technique, the complex relative permittivity and permeability of the carbon powder from catalyzed carbon black (CPCCB) were measured in the X and Ku bands. Based on these values and existing absorption models, electromagnetic wave absorption properties of CPCCB/paraffin wax composite was simulated, and a quantitative agreement between the simulated and the experimental data was obtained in the X and Ku bands. The effects of thickness on the CPCCB/wax composite were studied. It was found that an optimum thickness of the absorber needed to yield the maximum reflection loss could be obtained over a broad frequency region by simulation techniques. PACS 81.05.Uw; 61.10.Nz; 61.72.Bb; 61.50.Lt