Uniform Electromagnetic Field Research Articles

DOUBLE-WAVE DESCRIPTION OF THE MOTION OF SPINNING ELECTRON IN BOTH ELECTROMAGNETIC FIELD AND TWO-DIMENSIONAL HARMONIC OSCILLATOR POTENTIAL FIELD

Quantum theory of double-wave function description (DWFD) is applied to describe the motion of spinning electron in both perpendicular uniform electromagnetic field and two-dimensional harmonic oscillator potential field.The time evolution equations of related mechanical quantities are derived.Furthermore,DWFD of spin-zero electron in the same fields is also given,and it is found that their classical limit results correspond to those of classical mechanics.

Charge radii and magnetic polarizabilities ofρandK*mesons in QCD string theory

The effective action for light mesons in external uniform static electromagnetic fields was obtained on the basis of QCD string theory. We imply that in the presence of light quarks the area law of the Wilson loop integral is valid. The approximation of the Nambu-Goto straight-line string is used to simplify the problem. The Coulomb-like short-range contribution which goes from one-gluon exchange is also neglected. We do not take into account spin-orbital and spin-spin interactions of quarks and observe the $\ensuremath{\rho}$ and ${K}^{*}$ mesons. The wave function of the meson ground state is the Airy function. Using the virial theorem we estimate the mean charge radii of mesons in terms of the string tension and the Airy function zero. On the basis of perturbative theory, in the small external magnetic field we find the diamagnetic polarizability of $\ensuremath{\rho}$ and ${K}^{*}$ mesons: ${\ensuremath{\beta}}_{\ensuremath{\rho}}=\ensuremath{-}0.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4} {\mathrm{fm}}^{3}, {\ensuremath{\beta}}_{{K}^{*}}=\ensuremath{-}0.57\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4} {\mathrm{fm}}^{3}.$

Exact solution of the Herrera equation of motion in classical electrodynamics

The Landau–Lifshitz equation is derived as a first-order iteration of the Lorentz–Dirac equation for the charged particle. In those cases with null electromagnetic field’s gradient, the Landau-Lifshitz gives the so named Herrera equation. A general method for the solution of the latter equation is presented and applied to the motion of a particle in a uniform electromagnetic field.

Electromagnetic Field Calculation and Energy Considerations in the Human Head for Mobile Communications Conditions

ABSTRACT The accurate estimation of the electromagnetic field inside the human head is of extreme importance, in mobile communications. A method based on the numerical method of moments, that takes into account both the induced eddy currents and the charge accumulation is presented, for the determination of the electric field intensity, the eddy current density and the S.A.R. inside the head. The excitation is a non uniform electromagnetic field, produced by a monopole antenna that is typically used in mobile communications. Examples for an inhomogeneous model of the head in cylindrical coordinates are given.

Effective action for Dirac spinors in the presence of general uniform electromagnetic fields

Some new expressions are found, concerning the one-loop effective action of four dimensional massive and massless Dirac fermions in the presence of general uniform electric and magnetic fields, with $\vec E\cdot \vec H\neq 0$ and $\vec E ^2\neq \vec H ^2$. The rate of pair-production is computed and briefly discussed.

Shape optimization of W/G structure for uniform field illumination

The shapes of waveguide structures are optimized for the uniform electromagnetic field illumination. The vector finite element method is used as an analysis method. As the design algorithm, we employ the shape optimization with a design sensitivity analysis. Performance measure function representing the field uniformity is defined in this paper and used for the calculation of the design sensitivity. The design procedure is applied to the H-plane shape optimization in the rectangular cavity structure with a rectangular waveguide feeder and the E-plane shape optimization in the two plates waveguide.

Microwave Sintering of Ceramic Rods: Experiments and Models

Heat transfer analysis is used to model temperatures in a ceramic rod heated in a microwave resonant cavity, while stationary and while moving through the cavity at a steady speed. The calculated temperatures were compared to measured temperatures from carefully controlled experiments using a traveling wave tube microwave source. The model results assuming uniform electromagnetic fields help to explain some features of the experiments thought to be attributable to nonuniform field patterns in the applicator.This work is the first step in the development of applicator designs and heating control strategies for continuous processing of thermal runaway materials, such as metal oxide ceramic fibers.

A study of the thermoelastic behavior of a cylinder of low electrical conductivity in a uniform steady external electromagnetic field

We determine and study the temperature fields and stresses in a cylinder of low electrical conductivity resulting from force and thermal actions on it by a uniform external electromagnetic field. We study resonance phenomena and the behavior of the unknown fields in the vicinity of the resonance frequencies of the electromagnetic field.

Spin factor in the path integral representation for the Dirac propagator in external fields

We study the spin factor problem both in $3+1$ and $2+1$ dimensions which are essentially different for spin factor construction. Doing all Grassmann integrations in the corresponding path integral representations for Dirac propagator we get representations with spin factor in arbitrary external field. Thus, the propagator appears to be presented by means of bosonic path integral only. In $3+1$ dimensions we present a simple derivation of spin factor avoiding some unnecessary steps in the original brief letter (Gitman, Shvartsman, Phys. Lett. {\bf B318} (1993) 122) which themselves need some additional justification. In this way the meaning of the surprising possibility of complete integration over Grassmann variables gets clear. In $2+1$ dimensions the derivation of the spin factor is completely original. Then we use the representations with spin factor for calculations of the propagator in some configurations of external fields. Namely, in constant uniform electromagnetic field and in its combination with a plane wave field.

The secret life of the dipole

Surprisingly, neutral particles (such as neutrons) with electric dipoles can be accelerated by uniform electromagnetic fields. The force responsible, a consequence of the so-called hidden momentum of the dipole, has never been seen, but with the right field arrangement its effect on a neutron beam should be detectable.

Effective action of (2+1)-dimensional QED: The effect of a finite fermion density

The effective action of (2+1)-dimensional QED with finite fermion density is calculated in a uniform electromagnetic field. It is shown that the integer quantum Hall effect and de Haas-van Alphen like phenomena in condensed matter physics are derived directly from the effective action.

Charged particle in a constant electromagnetic field: Covariant solution

We present a fully covariant solution to the problem of a charged particle in a time-independent, spatially uniform electromagnetic field Fαβ. No restrictions are imposed on the strengths or orientations of the electric and magnetic fields E, B. Our general result is then applied to a few special cases, and the answers are shown to reduce to expressions available in the literature once a specific inertial frame is chosen.

ONE-LOOP FREE ENERGY FOR D-BRANES IN CONSTANT ELECTROMAGNETIC FIELD

We calculate the one-loop free energy for two parallel D-branes connected by open bosonic (neutral or charged) string in a constant uniform electromagnetic (EM) field at nonzero temperature. For neutral string, external EM field contribution appears as multiplier (Born-Infeld type action) of one-loop quantities without the external EM field. The Hagedorn temperature is not changed if compare with the case of standard string gas in the constant electromagnetic field.

One-loop vacuum amplitude for D-branes in constant electromagnetic field

Following Polchinski's approach we calculate the one-loop vacuum amplitude for two parallel D-branes connected by open bosonic (neutral or charged) string in a constant uniform electromagnetic (EM) field. For neutral string, an external EM field contribution appears as a multiplier (Born-Infeld type action) of the vacuum amplitude without external EM field. Hence, this gives an alternative way to see the inducing of Born-Infeld type action for the description of D-branes. For charged string the situation is more complicated, and may indicate the necessity to modify the induced D-branes action in this case.

THE PROPER TIME EQUATION AND THE ZAMOLODCHIKOV METRIC

The connection between the proper time equation and the Zamolodchikov metric is discussed. The connection is twofold. First, as already known, the proper time equation is the product of the Zamolodchikov metric and the renormalization group beta function. Second, the condition that the two-point function is the Zamolodchikov metric implies the proper time equation. We study the massless vector of the open string in detail. In the exactly calculable case of a uniform electromagnetic field strength we recover the Born-Infeld equation. We describe the systematics of the perturbative evaluation of the gauge-invariant proper time equation for the massless vector field. The method is valid for nonuniform fields and gives results that are exact to all orders in derivatives. As a nontrivial check, we show that in the limit of uniform fields it reproduces the lowest order Born-Infeld equation.

Stability of a radiation-absorbing ionizing shock wave in an electromagnetic field

The linear stability of a radiation-absorbing ionizing shock wave (light detonation waves) in the presence of a uniform electromagnetic field is investigated. The applied electric field is considered to be normal to the wave front and the magnetic field to be parallel to the front and perpendicular to the plane in which perturbations propagate. The medium satisfies a two-parameter equation of state. Analytic stability criteria are obtained. For a perfect gas the effect of the electromagnetic field and radiation on shock wave stability is determined.

Some Studies of the Neutron's Dirac Equation

In this paper, we continue the discussion for the neutron's Dirac equation and relevant problems after Ref.[1]. We consider the neutron's Dirac equation with the electric moment besides the magnetic moment, solve rigorously the neutron's Dirac equation in a uniform electromagnetic field. We also set up a relativistic neutron's spin-echo theory with a magnetic moment.

Neutron acceleration in uniform electromagnetic fields.

The question as to whether neutron acceleration can occur in uniform electromagnetic fields is examined. Although such an effect has been predicted using the canonical equations of motion some doubt has been raised recently as to whether it is in principle observable for a spin 1/2 particle. To resolve this issue a gedanken experiment is proposed and analyzed using a wave packet construction for the neutron beam. By allowing arbitrary orientation for the neutron spin as well as for the electric and magnetic fields a non vanishing acceleration of the center of the neutron wave packet is found which confirms the predictions of the canonical formalism.

Relativistic neutron spin-echo theory

We consider the neutron Dirac equation with electric moment in addition to magnetic moment, solve it rigorously in a uniform electromagnetic field, and set up the relativistic neutron spin-echo theory with a magnetic moment. We also solve the equation in an alternating magnetic field.

Relativistic magnetic top in electromagnetic fields

The precision of a relativistic magnetic top (a point magnetic moment that executes translational motion as it rotates) in special electromagnetic field configuration is investigated. The directions of the intrinsic torque (spin) and the magnetic moment of the top are assumed to coincide. A novel representation of the classical spin equations is given, and the criterion of free motion is formulated for the magnetic top. General solutions of the spin precession equations is constant and uniform electromagnetic fields are obtained for any direction of motion of the top. Special cases of constant fields are discussed: a uniform magnetic field; mutually orthogonal electric field and magnetic field, both uniform (E<H). It is shown how the solutions in the vector and tensor descriptions of the spin are related to the solution of its precession equation specified in the proper rest frame of the top.