Electromagnetic emission of a strongly charged oscillating droplet

Analytical expressions for electric field in the vicinity of an oscillating strongly charged droplet of nonviscous conducting liquid and intensity of electromagnetic radiation are derived in the linear approximation with respect to perturbation amplitude of the droplet surface. Order-of-magnitude estimations of the radiation intensity are presented. The intensity of electromagnetic radiation of a ball lightning that can be simulated using a charged droplet is not related to the surface oscillations.     

Gravitational Faraday-effect

The influence of the gravitational field upon the direction of polarization of electromagnetic radiation is generally discussed and for the special case of the gravitational field of a rotating homogeneous ring quantitatively calculated in linear approximation.     

Spontaneous excitation of a circularly accelerated atom coupled with vacuum Dirac field fluctuations

We study the spontaneous excitation of a circularly accelerated atom coupled with vacuum Dirac field fluctuations by separately calculating the contribution to the excitation rate of vacuum fluctuations and a cross term which involves both vacuum fluctuations and radiation reaction, and demonstrate that although the spontaneous excitation for the atom in its ground state would occur in vacuum, such atoms in circular motion do not perceive a pure thermal radiation as their counterparts in linear acceleration do since the transition rates of the atom do not contain the Planckian factor characterizing a thermal bath. We also find that the contribution of the cross term that plays the same role as that of radiation reaction in the scalar and electromagnetic fields cases differs for atoms in circular motion from those in linear acceleration. This suggests that the conclusion drawn for atoms coupled with the scalar and electromagnetic fields that the contribution of radiation reaction to the mean rate of change of atomic energy does not vary as the trajectory of the atom changes from linear acceleration to circular motion is not a general trait that applies to the Dirac field where the role of radiation reaction is played by the cross term.     

Electron Radiation Power in Graphene

Russian Physics Journal - Dynamics and radiation of a charged particle moving in a constant electromagnetic field and possessing a linear dispersion law ε(p)?=?νF|p| are...     

About the linewidth of cyclotron resonance in band-gap graphene

The critical amplitude of circularly polarized electromagnetic wave when the hysteresis of cyclotron absorption takes place, was found for band-gap graphene. The dependence of critical amplitude on the gap value and on the relaxation time was investigated. The conditions of applicability of linear theory describing the electromagnetic response of band-gap graphene in a non-zero magnetic field were found. The power of the circularly polarized electromagnetic radiation absorbed by band-gap graphene in the presence of a magnetic field was calculated. The linewidth of cyclotron absorption was shown to be not zero even for pure band-gap graphene.     

Decomposition of the total momentum in a linear dielectric into field and matter components

The long-standing resolution of the Abraham–Minkowski electromagnetic momentum controversy is predicated on a decomposition of the total momentum of a closed continuum electrodynamic system into separate field and matter components. Using a microscopic model of a simple linear dielectric, we derive Lagrangian equations of motion for the electric dipoles and show that the dielectric can be treated as a collection of stationary simple harmonic oscillators that are driven by the electric field and produce a polarization field in response. The macroscopic energy and momentum are defined in terms of the electric, magnetic, and polarization fields that travel through the dielectric together as a pulse of electromagnetic radiation. We conclude that both the macroscopic total energy and the macroscopic total momentum are entirely electromagnetic in nature for a simple linear dielectric in the absence of significant reflections.     

Amplification of electromagnetic field in the course of the nonrelativistic electron scattering by ion in the presence of the field of the medium-intensity elliptically polarized light wave

The amplification factor of the electromagnetic field is theoretically studied for the scattering of nonrelativistic electrons by ions in the presence of the field of the elliptically polarized electromagnetic wave. A simple analytical formula for the gain is derived for the medium-intensity range. The formula supplements and extends the domain of applicability of the known Marcuse formula for the linear polarization in the presence of a weak field. It is demonstrated that the maximum gain is reached when the initial electron velocities belong to the polarization plane of the electromagnetic wave. In the range of optical frequencies, the amplification factor of the laser radiation can be significant for relatively high powers of electron beams.     

Nonlinear properties of gated graphene in a strong electromagnetic field

We develop a microscopic theory of a strong electromagnetic field interaction with gated bilayer graphene. Quantum kinetic equations for density matrix are obtained using a tight binding approach within second quantized Hamiltonian in an intense laser field. We show that adiabatically changing the gate potentials with time may produce (at resonant photon energy) a full inversion of the electron population with high density between valence and conduction bands. In the linear regime, excitonic absorption of an electromagnetic radiation in a graphene monolayer with opened energy gap is also studied.     

狭窄波束型高频引力辐射与电磁场的作用效应

从弱引力场的Einstein-Maxwell方程出发,讨论了晶体空间阵列的狭窄波束型高频引力辐射与电磁场的作用效应,并给出了扰动解。计算表明,在TT(Transvese Traceless)坐标系中,最优辐射方向的引力波束是纯十型极化的,并可使同频的电磁波产生倍频的扰动效应,使静态电磁场产生与时间成线性关系的累积扰动效应。对于任意方向上的引力辐射波束,在垂直于引力波矢的平面内仍然是纯十型极化的。在高频辐射和实验室典型尺度条件下,TT坐标系与Fermi坐标系的差异是可以忽略的。 关键词：     

Radiation of scalar waves by the discontinuities in the antenna geometries

The electrical scalar potential satisfies the Helmholtz equation for time-harmonic waves and Aharonov-Bohm showed that the electromagnetic potentials have physical reality. For these reasons, the scalar potential represents scalar wave propagation in space. The gradient of the scalar wave leads to the electric field intensity, but it does not create the magnetic field. The criteria for the radiation of the scalar waves are studied on various linear antennas. The radiation integrals of the antennas are evaluated asymptotically by taking into account the edge effects. The radiation diagrams are plotted numerically and the phase velocities of the scalar waves are investigated in the near field.     

细胞骨架微管中水分子Kerr效应对电磁场辐射的影响

微管是细胞骨架的主要组成成分和功能组件,其中充满了属于Kerr介质的液体水。本文运用量子场论路径积分方法,研究微管中水分子与电磁场的相互作用。为了考虑Kerr效应,在系统的哈密顿量中引入电磁场的非谐项。我们给出了含有Kerr非线性项的电磁辐射运动方程,进而讨论了Kerr效应对电偶极子集体辐射的影响。     

AC-driven bilayer graphene: quasienergy spectrum of electrons and generation of soliton-like electromagnetic pulse

Quasienergy spectrum of electrons in biased bigraphene subjected to the linear polarized high-frequency electromagnetic radiation has been derived. Quasienergy bands of ac-driven bigraphene have been investigated. Dynamical appearing of the saddle points in band structure of biased bigraphene and energy gap modification have been predicted. Electromagnetic field equation has been written using obtained quasienergy spectrum. The solution corresponding to the soliton-like electromagnetic wave has been obtained. The conditions of soliton-like wave generation in ac-driven bigraphene have been discussed.     

无线电波发射设施周边环境电磁波检测技术

电磁波检测技术的应用,可以防止对人体的辐射。当今无线通讯技术迅猛发展,如何对变电所及输电线与移动电话基地台所产生的电磁场强度进行评估,便成为一个重要的工作。通过分析电磁波特征,提出了对这些电磁波辐射设施所产生的电磁场强度检测的方法。     

Radiation Reaction of a Nonrelativistic Quantum Charged Particle

An alternative approach to analyze the nonrelativistic quantum dynamics of a rigid and extended charged particle taking into account the radiation reaction is discussed with detail. Interpretation of the field operators as annihilation and creation ones, theory of perturbations and renormalization are not used. The analysis is carried out in the Heisenberg picture with the electromagnetic field expanded in a complete orthogonal basis set of functions which allows the electromagnetic field to satisfy arbitrary boundary conditions. The corresponding coefficients are the field operators which satisfy the usual commutation relations. A nonlinear equation of motion for the charged particle is obtained. A careful consideration of the quantum effects allows the derivation of a linear equation of motion which is free of both runaway solutions and preacceleration, even for a point charge. Also, the electromagnetic mass, which is defined as the coefficient of the acceleration operator, vanishes for a point particle. However, this does not mean that the results are free of ambiguities which are exhibited and discussed.     

三电极气体火花开关导通电流及其电磁辐射特性

针对三电极气体火花开关工作时产生的强电磁辐射,首先对开关的导通电流及其电磁辐射进行了理论分析,利用CST电磁仿真软件对气体火花开关开展了静电场仿真研究,分析了开关短程导通时的击穿场强;其次对三电极气体火花开关的导通电流和远场辐射场强进行了实验测量,对实验结果进行分析和总结;最后采用电磁屏蔽方法对开关的强电磁辐射进行了有效抑制。研究结果可以为有关脉冲功率装置的电磁辐射及防护提供参考和借鉴。     

On the Number of Photons in a Classical Electromagnetic Field

Relations determining the number of photons in an electromagnetic field are considered from the point of view of a classical electromagnetic field. A relativistically invariant expression is obtained for the number of emitted photons in terms of charges and currents producing the electromagnetic field. Examples are considered for calculating the numbers of photons in the electromagnetic field for the case of the electric dipole radiation field, as well as the field of a finite and spatially restricted electromagnetic pulse.     

Superluminal,advanced and retarded propagation of electromagnetic potentials in quantum mechanics

In some gauges part of the classical electromagnetic potentials can propagate faster than the speed of light. In other gauges part of the electromagnetic potentials can be advanced, even though the electromagnetic field is retarded. If the conventional interaction between electromagnetic radiation and quantum mechanical charged particles, which involves the vector and scalar potentials, is used, an atom has a nonzero probability of being excited before the electromagnetic field arrives. If part of the potentials are advanced, the atom could even be excited before the sources are turned on. These spurious effects, which are gauge dependent and violate energy conservation, relativity, and causality, are due to use the conventional (gauge-dependent) interaction. When the interaction of the electromagnetic radiation and matter is treated in a manifestly gauge-invariant way, the atom is not excited before the electromagnetic field arrives, regardless of which gauge is used.     

Hawking Radiation of Reissner-Nordstr<Emphasis Type="Italic">ö</Emphasis>m Black Hole in Electromagnetic Field with Einstein Tensor Corrections

In this paper, we have investigated the absorption probability and Hawking radiation of electromagnetic field while it coupling with Einstein tensor in the background of 4-dimensional Reissner-Nordström(RN) black hole spacetime. Our results indicate that the properties of the absorption probability and Hawking radiation depend not only on the coupling parameter, but also on the parity of the electromagnetic field, which is quite different from those of the usual electromagnetic field without coupling in the 4-dimensional spacetime.The absorption probability, power emission spectra and luminosity of Hawking radiation decreases with the increase of coupling parameter α when the coupled electromagnetic field have odd-parity, and increases with the increase of coupling parameter α when the coupled electromagnetic field have even-parity.     

Properties of Near and Far Fields for the Electric Line Source Illumination of a Lossy Metamaterial Covered Dielectric Cylinder

The electric field properties of the electric line source radiation in the presence of a lossy metamaterial covered dielectric cylinder are investigated. Firstly, the electromagnetic model configuration is given. The exact solution of the electromagnetic is presented. Secondly, the near field and the far field properties are investigated according to the electromagnetic and geometrical parameters. The different “focus” phenomenon, the directivities and the normalized radiation resistance are discussed and important conclusions are obtained. During all the numerical computation, the lossy conventional material covered dielectric cylinder is utilized as the reference.