The analysis of Aguirregabiria, Hernandez, and Rivas [2004 Eur. J. Phys. 25, 555--567] of the electromagnetic linear momentum in quasistatic systems omits the presence of an equal and opposite hidden mechanical momentum in such systems. The existence of hidden mechanical momentum ensures that the action--reaction law holds for the forces between the charge- and current-carrying bodies of a quasistatic system, and thus the total mechanical momentum associated with the motion of such bodies in a closed quasistatic system is conserved.
Fresnel's equations describe reflection and transmission of electromagnetic waves at an interface between two media. It turns out that these equations can be used in quasistatics and even statics, for example to straightforwardly calculate magnetic forces between a permanent magnet and a bulk medium. This leads to a generalization of the classical image method.
The incorporation of a relativistic momentum of a nonelectromagnetic nature into macroscopic problems of electrodynamics obviates the lack of correspondence between the electromagnetic mass and the electromagnetic momentum of macroscopic bodies, allowing, in particular, the resolution of the well-known 4/3 paradox.
A new form of the energy-momentum tensor of the interaction of an electromagnetic field with a non-conducting medium. The wave equations. The electromagnetic forces
We present an elementary discussion of the momentum transferred by an electromagnetic wave propagating in a dispersive medium. Our analysis is based on Minkowski's electromagnetic momentum density which have been recently seen to be consistent with a fully covariant expression of the energy-momentum tensor of the electromagnetic field in a dispersive medium and with all the experimental evidence. We show that the medium may be either pulled or pushed as the electromagnetic pulse enters in it depending on the value of the frequency.
On the basis of a non-local Lagrangian for Maxwell equations in a dispersive medium, the energy-momentum tensor of the field is derived. We obtain the Field equations through variational methods and an extension of Noether theorem for a non-local Lagrangian is obtained as well. The electromagnetic energy-momentum tensor obtained in the general context is then specialized to the case of a field with slowly varying amplitude on a rapidly oscillating carrier.
The self-force of a point charge moving on a rectilinear trajectory is obtained, with no need of any explicit removal of infinities, as the negative of the time rate of change of the momentum of its retarded self-field.
Invoking Maxwell's classical electrodynamics in conjunction with expressions for the electromagnetic (EM) energy, momentum, force, and torque, we use a few simple examples to demonstrate the nature of linear and angular momentum exchange between a wave-packet and a small spherical particle. The linear and angular momenta of the EM field, when absorbed by the particle, will be seen to elicit different responses from the particle.
To model momentum exchange in nonlinear wave-particle interaction, as in amplification devices like traveling-wave tubes, we use an $N$-body self-consistent hamiltonian description based on Kuznetsov's discrete model, and we provide new formulations for the electromagnetic power and the conserved momentum. This approach leads to fast and accurate numerical simulations in time domain and in one dimensional space.
The form of the energy-momentum tensor when a quasimonochromatic field propagates into and through an antireflection-coated, sourceless, transparent, continuous, linear magneto-dielectric medium, initially at rest in the local frame, remains controversial. The Minkowski energy-momentum tensor is the main component of the electromagnetic conservation law. It has been known for over a century that the electromagnetic conservation law is unsound as evidenced by alternative energy-momentum tensors that have been proposed to ameliorate known physical deficiencies (violation of conservation of angul…
The total momentum of a thermodynamically closed system is unique, as is the total energy. Nevertheless, there is continuing confusion concerning the correct form of the momentum and the energy-momentum tensor for an electromagnetic field interacting with a linear dielectric medium. Here we investigate the energy and momentum in a closed system composed of a propagating electromagnetic field and a negligibly reflecting dielectric. The Gordon momentum is easily identified as the total momentum by the fact that it is, by virtue of being invariant in time, conserved. We construct continuity equat…
Radiation pressure and the linear momentum of the electromagnetic field in magnetic media
我们研究的力的电磁辐射的线性，各向同性，均匀介质中指定的电容率ε和磁导率μ。提出了磁化强度M上的电磁洛伦兹力的公式，这里将其视为安培电流回路。使用所提出的公式，我们证明了动量守恒在几种情况下，是经得起严格的分析的基础上，经典的麦克斯韦方程组，洛伦兹定律的力量，和本构关系。我们的分析产生精确的表达式的介质内的电磁和机械动量的密度指定的（μ，μ）参数。这种分析的一个有趣的结果是确定了一种“内禀”机械动量密度ExM/c^2，它类似于电磁（或亚伯拉罕）动量密度ExH/c^2。(Here E和H分别是电场和磁场的大小，c是真空中的光速。）在存在电场E的情况下，与磁化强度M相关的这种固有机械动量显然与W所预测的“隐藏”动量相同。Shockley和R. P. James在近40年前
For electromagnetic field theories, canonical energy-momentum conservation laws can be derived from the underpinning spacetime translation symmetry according to the Noether procedure. However, the canonical Energy-Momentum Tensors (EMTs) are neither symmetric nor gauge-symmetric (gauge invariant). The Belinfante-Rosenfeld (BR) method is a well-known procedure to symmetrize the EMTs, which also renders them gauge symmetric for first-order field theories. High-order electromagnetic field theories appear in the study of gyrokinetic systems for magnetized plasmas and the Podolsky system for the ra…
Angular Momentum of Electromagnetic Radiation. Fundamental physics applied to the radio domain for innovative studies of space and development of new concepts in wireless communications
