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Vector displacements expressed in spherical coordinates are proposed. They correspond to electromagnetic fields in vacuum that globally rotate about an axis and display many circular patterns on the surface of a sphere. The fields basically…

Classical Physics · Physics 2021-06-11 Daniele Funaro

Magnetic helicity is a physical quantity that describes field topology. It is also a conserved quantity as Berger in 1984 demonstrated that the total magnetic helicity is still conserved in the corona even when there is a fast magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-12 Mei Zhang

The field of an electromagnetic (E) dipole has been examined using general relativistic (R) and quantum mechanical (Q) points of view, and an E=Q=R equivalence principle presented whereas the curvature of the electromagnetic streamlines of…

General Physics · Physics 2007-05-23 V. F. Tamari

The energy of the stochastic magnetic field is bounded from below by a topological quantity expressing the degree of linkage of the field lines. When the bound is saturated one can assume that the storage of a certain magnetic energy…

Plasma Physics · Physics 2007-05-23 F. Spineanu , M. Vlad

The singularities of the electromagnetic field are derived to include all the point-like multipoles representing an electric charge and current distribution. Firstly derived in the static case, the result is generalized to the dynamic one.…

Classical Physics · Physics 2015-05-14 C. Vrejoiu , R. Zus

It is shown that the helicity amplitudes can be used to describe and analyze the properties of the electromagnetic field in classical and in quantum theory. On the one hand they embody the relativistic content of electromagnetic theory. On…

Optics · Physics 2019-08-06 Iwo Bialynicki-Birula

In helical hydromagnetic turbulence with an imposed magnetic field (which is constant in space and time) the magnetic helicity of the field within a periodic domain is no longer an invariant of the ideal equations. Alternatively, there is a…

Astrophysics · Physics 2009-11-07 Axel Brandenburg , William H. Matthaeus

For an oscillating electric dipole in the shape of a small, solid, uniformly-polarized, spherical particle, we compute the self-field as well as the radiated electromagnetic field in the surrounding free space. The assumed geometry enables…

Classical Physics · Physics 2020-08-21 Masud Mansuripur , Per K. Jakobsen

We study theoretically by means of quantum electrodynamics the vortex radiation of a relativistic electron in a uniform magnetic field. The exact expressions for the probability of emission of a photon with a certain angular momentum are…

Quantum Physics · Physics 2023-03-17 Vladimir Epp , Ulyana Guselnikova

The electric and magnetic fields of a spatio-temporally varying electric current loop are calculated using the Jefimenko equations. The radiation and the nonradiation parts of the electromagnetic fields are derived in the framework of…

Classical Physics · Physics 2013-04-15 Markus Lazar

Strong rotating magnetic fields may cause a precession of the electron's spin around the rotation axis of the magnetic field. The superposition of two counterpropagating laser beams with circular polarization and opposite helicity features…

Quantum Physics · Physics 2014-10-17 Sven Ahrens , Heiko Bauke , Christoph H. Keitel , Rainer Grobe

We consider the radiation field operators in a cavity with varying dielectric medium in terms of solutions of Heisenberg's equations of motion for the most general one-dimensional quadratic Hamiltonian. Explicit solutions of these equations…

Mathematical Physics · Physics 2015-06-12 Christian Krattenthaler , Sergey I. Kryuchkov , Alex Mahalov , Sergei K. Suslov

We calculate the helicity and chirality effects experienced by a spin-1/2 particle subjected to classical electromagnetic and gravitational fields. The helicity evolution is then determined in the non-relativistic, relativistic, and…

High Energy Physics - Phenomenology · Physics 2015-06-25 Dinesh Singh , Nader Mobed , Giorgio Papini

Newly emerging magnetic flux can show a complicated linked or interwoven topology of the magnetic field. The complexity of this linkage or knottedness of magnetic flux is related to the free energy stored in the magnetic field. Magnetic…

Astrophysics · Physics 2007-05-23 Gunnar Hornig

Maxwell's equations allow for some remarkable solutions consisting of pulsed beams of light which have linked and knotted field lines. The preservation of the topological structure of the field lines in these solutions has previously been…

Optics · Physics 2015-05-30 William T. M. Irvine

The Hamiltonian formulation of the motion of a spinning relativistic particle in an external electromagnetic field is considered. The approach is based on the introduction of new coordinates and their conjugated momenta to describe the spin…

High Energy Physics - Theory · Physics 2014-11-18 M. Chaichian , R. Gonzalez Felipe , D. Louis Martinez

The Hamiltonian of relativistic particles with electric and magnetic dipole moments that interact with an electromagnetic field is determined in the Foldy-Wouthuysen representation. Transition to the semiclassical approximation is carried…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. J. Silenko

Field line helicity measures the net linking of magnetic flux with a single magnetic field line. It offers a finer topological description than the usual global magnetic helicity integral, while still being invariant in an ideal evolution…

Solar and Stellar Astrophysics · Physics 2023-11-16 A. R. Yeates , M. A. Berger

We compute electromagnetic fields created by a relativistic charged spin-half particle in empty space at distances comparable to the particle Compton wavelength. The particle is described as a wave packet evolving according to the Dirac…

High Energy Physics - Phenomenology · Physics 2017-06-28 Balthazar Peroutka , Kirill Tuchin

The electromagnetic field generated by a charged particle moving along a helical orbit inside a dielectric cylinder immersed into a homogeneous medium is investigated. Expressions are derived for the electromagnetic potentials, electric and…

High Energy Physics - Theory · Physics 2008-11-26 A. A. Saharian , A. S. Kotanjyan , M. L. Grigoryan