Dispersion of bulk and surface electromagnetic waves in bigyrotropic finely stratified ferrite-semiconductor medium

Expressions for effective parameters are derived for a medium composed of alternating layers of a uniaxial ferromagnet and a semiconductor. The medium under investigation is a biaxial bigyrotropic crystal. In the case of a transverse magnetooptical configuration, bulk and surface waves at the vacuum-periodic structure interface are considered. Numerical analysis of dispersion relations for intrinsic TE and TM modes controlled in different frequency ranges is carried out.     

Positive-, negative-, and orthogonal-phase-velocity propagation of electromagnetic plane waves in a simply moving medium

Planewave propagation in a simply moving, dielectric-magnetic medium that is isotropic in the co-moving reference frame, is classified into three different categories: positive-, negative-, and orthogonal-phase-velocity (PPV, NPV, and OPV). Calculations from the perspective of an observer located in a non-co-moving reference frame show that, whether the nature of planewave propagation is PPV or NPV (or OPV in the case of non-dissipative mediums) depends strongly upon the magnitude and direction of that observer's velocity relative to the medium. PPV propagation is characterized by a positive real wavenumber, NPV propagation by a negative real wavenumber. OPV propagation only occurs for non-dissipative mediums, but weakly dissipative mediums can support nearly OPV propagation.     

Propagation of electromagnetic waves in a conducting magnetic medium

We study helicon-spin waves (hybrid polaritons) in a ferromagnetic conducting medium in a strong static magnetic field and determine their existence domains. It is shown that the spatial dispersion of the conductivity tensor gives rise to collisionless damping of these waves when they propagate obliquely to the magnetic field. In the absence of collisionless damping (for wave propagation along the magnetic field), the conditions of amplification of hybrid polaritons in a static electric field are determined. Institute of Radiophysics and Electronics, National Academy of Sciences of Ukraine, Kharkov, Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol.43, No. 1, pp. 38–44, January 2000.     

Dispersion of photon density waves in a strongly scattering medium

In the approximation of the radiation transfer equation, the damping decrement and the velocity of photon density waves propagating in a strongly scattering medium are studied as functions of the increasing modulation frequency of the source of radiation up to the microwave frequency range. The results obtained for microwave frequencies are found to be in qualitative agreement with those derived from the Bethe-Salpeter equation.     

介质运动时的电磁规律

静止时线性、均匀、各向同性的介质，当它运动时变得不再各向同性，其标志是光线和波法线分离，波面形状由球面变成椭球面．本文给出了非各向同性介质与介质运动速度间的定量关系，导出了电磁波在运动介质表面反射和折射的普遍规律．并且就介质的运动方向与介质表面垂直或平行两种特殊情形进行了较为详细的分析。     

Dispersion relation for electromagnetic waves in anisotropic media

Electromagnetic wave propagation in anisotropic dielectric media with two generic matrices εij and μij of permittivity and permeability is studied. In the framework of a metric-free electrodynamics approach, a compact tensorial dispersion relation is derived. The derivation does not require the corresponding matrices to be symmetric, positive definite, nor even invertible. The resulting formula is useful for a theoretical and experimental study of electromagnetic wave propagation in a wide class of linear media.     

Generation of electromagnetic waves in a spheroidal conductor by moving charges

The surface polarization fields generated by a charge moving near a spheroidal conductor are considered. The relations for surface plasmon dispersion are obtained. The polarization fields and energy losses of a moving charge are calculated.     

运动介质的电磁性质方程

应用电磁场张量、电磁感应张量和它们的对偶张量讨论运动介质的电磁性质方程,指出D=εE和B=μH在运动介质中不成立,给出运动介质电磁性质方程的协变形式、向量形式.     

Transformation of electromagnetic radiation at moving inhomogeneities of a medium

The possibility of a significant up-conversion of the electromagnetic-radiation frequency due to its Doppler shift by ultrarelativistic nonlinear-medium inhomogeneities induced by high-intensity counterpropagating radiation pulses is analyzed. It is shown that the efficiency of parametric redistribution increases resonantly as the velocity of the inhomogeneity approaches the phase velocity of the high-frequency radiation.     

Dispersion relation of linearly polarized strong electromagnetic waves

We present a numerical study of the dispersion relation of linearly polarized strong electromagnetic waves in a cold electron plasma. The nonlinear effects introduced by the relativistic motion of electrons are: 1) the dispersion relation depends explicitly on the field strength $\text{α =}\text{eE}{}_{\mathrm{<mtext>o</mtext>}}\text{mc ω}{}_{\mathrm{<mtext>o</mtext>}}$, and 2) the propagation of modes with frequencies below the formal electron plasma frequency is allowed.     

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根据狭义相对性原理,应用Lorentz变换法则,从相对运动媒质静止参考系中的有关结论,获取了实验室参考系中所需结果。通过证明平面波相位是Lorentz不变量,指出实验室参考系中平面波解的存在性。由Lorentz变换导出了实验室参考系中平面波色散关系表示式,据此给出运动媒质的波动方程。由Lorentz变换导出运动媒质中平面波Maxwell方程。基于这些结果,应用Lorentz变换获得了平面波从自由空间垂直入射到各向同性运动等离子体半空间时反射波与透射波的有关特性。     

Diffraction of electromagnetic waves by a half-plane located in a moving cold plasma

Diffraction of plane electromagnetic waves by a conductive half-plane located in a parallel flow of cold plasma is studied. The velocity of the plasma motion and the propagation direction of the incident wave are normal to the half-plane edge. A general solution of the problem is obtained using the Wiener-Hopf-Fok method. The behavior of the field is analyzed far from the half-plane edge and in its vicinity. State University, Saint Petersburg, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 4, pp. 475–494, April, 1998.     

Interaction of waves with a birefringent medium moving with acceleration

Recent experiments demonstrated that the energy of a neutron traversing an accelerated sample of a refractive medium changes. Later, it was realized that such an accelerated-medium effect (AME) is quite a general phenomenon characteristic of waves and particles of different nature. This paper discusses some special features of the effect for a birefringent medium. In this case, AME shows quite new features. In neutron optics, where birefringence is due to the spin dependence of the refractive index, AME results in a nonstationary state with a precessing spin. In the case of the propagation of a two-flavor neutrino through an accelerated layer of matter, AME affects substantially the ensuing evolution of a neutrino flavor state as it propagates through a free space.