相关论文: Energy creation in a moving solenoid?
We discuss the relativistic transformation of the energy of a charged spherical capacitor. The energy stored in the electromagnetic fields observed by an uniformly moving frame is related to that of the rest frame by a factor different from…
There are various formulations of energy--momentum tensors for an electromagnetic field in a linear dielectric. The total energy--momentum tensor, comprised of electromagnetic and material components, must be unique. We discuss the…
We investigate the magneto--elastic equilibrium of a neutron star crust and magnetic energy stored by the elastic force. The solenoidal motion driven by the Lorentz force can be controlled by the magnetic elastic force, so that conditions…
The origin of electromagnetic momentum for general static charge-current distributions is examined. The electromagnetic momentum for static electromagnetic fields is derived by implementing conservation of momentum for the sum of mechanical…
Using superposition and numerical approximations of a published analytical expression for the magnetic field generated by a finite solenoid, we show that the magnetic field external to parallel identical solenoids can be nearly uniform and…
For magnetically driven events, the magnetic energy of the system is the prime energy reservoir that fuels the dynamical evolution. In the solar context, the free energy is one of the main indicators used in space weather forecasts to…
The magnetic field generated by an electron bound in a spherically symmetric potential is calculated for eigenstates of the orbital and total angular momentum. General expressions are presented for the current density in such states and the…
From the energy-momentum tensors of the electromagnetic field and the mechanical energy-momentum, the equations of energy conservation and balance of electromagnetic and mechanical forces are obtained. The equation for the Abraham force in…
By using the generalized version of the Shell Theorem analytical equations are derived to calculate the electric energy of a charged sphere and the field energy of the electrolyte inside and around the sphere. These electric energies are…
We derive the expressions for canonical energy, momentum, and angular momentum for multiple metric theories. We prove that although the metric fields are generally interacting, the total energy is the sum of conserved energies corresponding…
In moving electromagnetic systems, electromagnetic momentum calculated from the vector potential is shown to be proportional to the field energy of the system. The momentum thus obtained is shown actually to be the same as derived from a…
This scientific essay proposes to discuss the physical aspects of a system consisting of some non-relativistic massive charged particles, that are the sources in motion of an electromagnetic field (e.m.) propagating through the space,…
A proposal to store unsteady energy in potential energy via lifting masses with a rough quantitative overview. Some applications and methods to harvest the potential energy are also given. A focus is put on photovoltaically generated…
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…
The electromagnetic energy-momentum of a moving charged spherical capacitor may be calculated by a 4-vector Lorentz transformation from the energy in the rest frame. However, energy-momentum of the moving system computed directly from…
We comment on a recent paper regarding the derivation of the magnetic field components of a solenoid in analytical form by proposing a different and simpler method
The most general expressions of the stored energies for time-harmonic electromagnetic fields are derived from the time-domain Poynting theorem, and are valuable in characterizing the energy storage and transport properties of complex media.…
We evaluate the exact ${\rm QED}_{2+1}$ effective energy for charged spin zero and spin half fields in the presence of a family of static magnetic field profiles localized in a strip of width $\lambda$. The exact result yields an infinite…
Electromagnetism is a simple example of a gauge theory where the underlying potentials -- the vector and scalar potentials -- are defined only up to a gauge choice. The vector potential generates magnetic fields through its spatial…
In 1967 Shockley and James addressed the situation of a magnet in an electric field. The magnet is at rest and contains electromagnetic momentum, but there was no obvious mechanical momentum to balance this for momentum conservation. They…