Surfatron acceleration in electromagnetic waves with a low phase velocity

The possibility of unlimited surfatron acceleration of nonrelativistic charged particles by slow electromagnetic waves has been revealed. The capture into such an acceleration regime has been described. The region of the parameters in which the effect of the capture and acceleration exists has been considered. The contribution of this mechanism to an increase in the energy of charged particles in the Earth’s magnetosphere has been estimated.     

Solutions of scalar and electromagnetic wave equations in the metric of gravitational and electromagnetic waves

The wave equation for a scalar field ? and vector potentialA* are solved in the background metric of a gravitational wave. The corresponding solutions when the metric is generated by a plane electromagnetic wave, is obtained from these solutions. The solution for the scalar wave is discussed in detail. It is found that because of the interaction, two new waves are generated in the lower order approximations. One of them has the same phase dependence as the original wave while the other shows a transient character. There is no interaction when the waves are along the same direction.     

Radiation of a scalar particle in the field of two oppositely directed electromagnetic travelling waves

The radiation of a charged spinless particle in a field of two linearly polarized, oppositely directed electromagnetic travelling waves is treated in the small-field approximation. Equations are derived for the radiation probability, and the polarization properties of the radiation are studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, Vol. 12, No. 1, pp. 69–73, January, 1969.The authors thank Professor I. M. Ternov for interest in this study and useful discussions.     

Survey of cosmological models with gravitational,scalar and electromagnetic waves

This paper gives an overview and reviews some recent investigations of anisotropic and inhomogeneous models. A class of models, which admit an Abelian two-parameter group of isometries, is considered in detail. Within this class of models we present exact solutions of the Einstein field equations. These solutions describe inhomogeneous cosmological models containing gravitational, scalar and electromagnetic waves. The solutions are used to study the effect of the symmetry breaking in corresponding Bianchi models. The nonlinear dynamics of primordial inhomogeneities is considered. The global evolution of the inhomogeneous models considered is also investigated. Finally we discuss the validity of various assumptions, used in the earlier treatments of inhomogeneous models.     

Geometric phases for scalar wave superpositions

Geometric phases are defined for superpositions of scalar waves of various nature. The geometric phases possess similar properties to those of polarized light wave ones, but require a different parametric space. An appropriate parametric space is constructed on the basis of a modified Poincaré sphere. An example considering spherical scalar waves is presented.     

An approximation scheme for scalar waves in a Kerr geometry

An approximation scheme, analogous to ones previously considered for the Schwarzschild and Reissner-Nordström geometries, is applied to scalar waves in a Kerr geometry. Spectral curves of transmission coefficient for monochromatic, axially symmetric scalar waves imploding on a rotating black hole are calculated using the approximation scheme.Research supported in part by the Natural Sciences and Engineering Council of Canada.     

An approximation scheme for scalar waves in a Schwarzschild geometry

The Schwarzschild geometry is approximated by a certain set of conformally flat shells. As an example of the use of this approximation, the transmission coefficientT for spherical waves of monochromatic scalar radiation imploding on the black hole is calculated by solving the scalar wave equation within each conformally flat space and matching across the interfaces. The results agree with those of other authors for low and high frequencies and give values ofT at all intermediate frequencies.This work was supported by the National Research Council of Canada.     

Eigenmodes for electromagnetic waves propagating in a toroidalcavity

A solution has been attempted by means of the Helmholtz equation for an electromagnetic wave propagating in an empty torus in a system of toroidal coordinates. The electromagnetic fields are expressed in terms of the Hertz vector to obtain a scalar Helmholtz equation. The latter has been solved by making use of an inverse aspect ratio expansion of the solution. Unlike most previous workers, the authors have obtained their solutions in terms of hypergeometric functions whose static limit is the toroidal harmonics. The cylindrical solutions in terms of Bessel functions can also be recovered by taking the appropriate large aspect ratio limit. The eigenmodes, with arbitrary toroidal and poloidal mode numbers, have been obtained by applying the boundary conditions on the metallic walls of infinite conductivity, and they cannot be distinguished as TE or TM modes. Eigenfrequencies for various toroidal and poloidal mode numbers are plotted against the inverse aspect ratio. First-order approximations to the fields in the toroidal cavity have also been derived     

Geometric algebra and star products on the phase space

Superanalysis can be deformed with a fermionic star product into a Clifford calculus that is equivalent to geometric algebra. With this multivector formalism it is then possible to formulate Riemannian geometry and an inhomogeneous generalization of exterior calculus. Moreover, it is shown here how symplectic and Poisson geometry fit in this context. The application of this formalism together with the bosonic star product formalism of deformation quantization leads then on space and space-time to a natural appearance of spin structures and on phase space to BRST structures that were found in the path integral formulation of classical mechanics. Furthermore it will be shown that Poincaré and Lie-Poisson reduction can be formulated in this formalism.     

Interaction of electromagnetic waves with anisotropic collisional plasma half space

Interaction of electromagnetic waves penetrating into anisotropic semi-infinite collisional plasma embedded in a uniform external magnetic field is studied using half range Fourier transforms. General field equations are developed for fractionally accommodating boundary and a particular case of specular reflection is discussed both for right handed as well as left handed circularly polarized modes. Anisotropy effects are found to be more prominent in the continuum mode of field component. Anisotropy as well as collisions make the field to attain a constant value at a shorter distance. Left handed polarized modes are found to be more penetrating than right handed modes. Surface impedance is calculated and effects of collisions as well as anisotropy are discussed.     

超薄宽带平面聚焦超表面及其在高增益天线中的应用

针对相位梯度超表面在灵活操控电磁波与提高天线增益中的潜在应用,提出一种新型的宽带超表面单元,实现了在较宽频带范围内操控电磁波波前与提高天线增益.本文首先设计了一种圆环十字形对称单元来控制反射波的相移量,单元厚度为1 mm,尺寸为0.3λ_0(λ_0=20 mm),工作频段15—18 GHz,而后验证了由该单元组成的相位梯度超表面在15—18 GHz范围内对电磁波的奇异反射与聚焦特性.最后将设计的反射聚焦超表面应用于提高天线增益中,仿真与测试结果均表明,天线最高增益在15—18 GHz内平均增加了11 d B且-1 dB增益带宽为15—18 GHz(相对带宽为18.2%).由于厚度薄、重量轻、频带宽,设计的该单元拓展了相位梯度超表面在微波领域的应用,有望为高增益天线的实现提供新的方法.     

Long-range scalar field in conformally flat space-time

Consequences of a massless scalar field in conformally flat space-time are studied. Then a wide class of solutions of the scalar field is obtained.     

Geometric phase in a Bose-Einstein-Josephson junction

We calculate the geometric phase associated with the time evolution of the wave function of a Bose-Einstein condensate system in a double-well trap by using a model for tunneling between the wells. For a cyclic evolution, this phase is shown to be half the solid angle subtended by the evolution of a unit vector whose z-component and azimuthal angle are given, respectively, by the population difference and phase difference between the two condensates. For a non-cyclic evolution, an additional phase term arises. We show that the geometric phase can also be obtained by mapping the tunneling equations on to the equations of a space curve. The importance of a geometric phase in the context of some recent experiments is pointed out.     

Trace anomaly for gauge theories in a conformally flat space

We study the trace anomaly of the energy-momentum tensor for gauge theories coupled to massless fermions in the context of a self-consistent cooperative phenomenon for the creation of the universe.     

Joint behavior of longitudinal electromagnetic waves and scalar gravitational disturbances in the cosmological plasma with allowance for electron-photon collisions

The electric charge density induced by scalar gravitational perturbations in the radiation-dominated stage of the expansion of the universe is calculated on the basis of an investigation of the combined system of Einstein, Maxwell, and kinetic equations for a cosmological plasma with a model collision integral.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 97–100, February, 1992.     

An approximation scheme for scalar waves in a Reissner-Nordström geometry

The Reissner-Nordström geometry is approximated by a certain sequence of conformally flat shells. As an example of the use of this approximation, spectral curves of transmission coefficientT(w) vs. frequencyw are calculated for spherical waves of monochromatic scalar radiation imploding on the charged black hole by solving the scalar wave equation within each conformally flat space and matching across the interfaces. Spectral curves are found for several values of the charge that are less than or equal to the mass. For small charge, the results agree with those previously found in the Schwarzschild case.