An exact solution to the relativistic equation of motion of acharged particle driven by a linearly polarized electromagneticwave

An exact analytic solution is found for a basic electromagnetic wave-charged particle interaction by solving the nonlinear equations of motion. The particle position, velocity, and corresponding time are found to be explicit functions of the total phase of the wave. Particle position and velocity are thus implicit functions of time. Applications include describing the motion of a free electron driven by an intense laser beam     

The exact solution of the relativistic equation of motion of acharged particle driven by an elliptically polarized electromagneticwave

An exact solution of the relativistic equation of motion of a charged particle driven by an elliptically polarized electromagnetic wave is obtained. The method used for this purpose is simple, and the results of earlier authors for the linearly and circularly polarized waves can be recovered as special cases of the solution     

Heating of magnetic fluid systems driven by circularly polarized magnetic field

A theory is presented to calculate the heat dissipation of a magnetic suspension, a ferrofluid, driven by circularly polarized magnetic field. Theory is tested by in vitro experiments and it is shown that, regardless of the character of the relaxation process, linearly and circularly polarized magnetic field excitations, having the same root-mean-square magnitude, are equivalent in terms of heating efficiency.     

Relativistic motion of a charged particle driven by an ellipticallypolarized electromagnetic wave propagating along a static magnetic field

The relativistic equations of motion of the interaction of a charged particle with an electromagnetic wave of elliptic polarization propagating along the direction of an external and constant magnetic field are solved in exact form. The method of solution is straight forward and allows to recover results previously reported in the literature     

Multiphoton ionization of the hydrogen atom by a circularly polarized electromagnetic field

This paper examines the multiphoton ionization of the ground state of the hydrogen atom in the field of a circularly polarized intense electromagnetic wave. To describe the states of photoelectrons, quasiclassical wave functions are introduced that partially allow for the effect of an intense electromagnetic wave and that of the Coulomb potential. Expressions are derived for the angular and energy distributions of photoelectrons with energies much lower than the ionization potential of an unperturbed atom. It is found that, due to allowance for the Coulomb potential in the wave function of the final electron states, the transition probability near the ionization threshold tends to a finite value. In addition, the well-known selection rules for multiphoton transitions in a circularly polarized electromagnetic field are derived in a natural way. Finally, the results are compared with those obtained in the Keldysh-Faisal-Reiss approximation. Zh. éksp. Teor. Fiz. 116, 807–820 (September 1999)     

论恒力作用下质点的相对论运动

在相对论情况下，讨论了受恒力作用的质点的运动规律。     

An exact solution of Einstein's equation with a dilaton field

An exact solution of Einstein gravity coupled to a dilaton field is found. The solution is conformally flat and is invariant under Lorentz transformations. The singularities and conformal structure of the metric are examined.     

On the relativistic classical motion of a radiating spinning particle in a magnetic field

We propose classical equations of motion for a charged particle with magnetic moment, taking radiation reaction into account. This generalizes the Landau–Lifshitz equations for the spinless case. In the special case of spin-polarized motion in a constant magnetic field (synchrotron motion) we verify that the particle does lose energy. Previous proposals did not predict dissipation of energy and also suffered from runaway solutions analogous to those of the Lorentz–Dirac equations of motion.     

Reply to comment by E. Comay on the longitudinal magnetic field of circularly polarized electromagnetic waves

The argument presented by E. Comay in Ref. 1 is in error precisely at the point where he uses the Cartesian form of Stokes' theorem. His Comment is therefore erroneous and inconsequential.     

Interaction of radiation and a relativistic electron in motion in a constant magnetic field

This paper examines the effect of multiple photon emission on the quantum mechanical state of an electron emitting synchrotron radiation and on the intensity of that radiation. Calculations are done with a variant of perturbation theory based on the use of extended coherent states. A general formula is derived for the number of emitted photons, which allows taking into account their mutual interaction. A model problem is used to demonstrate the absence of the infrared catastrophe in the modified perturbation theory. Finally, the electron density matrix is calculated, and the analysis of this matrix makes it possible to conclude that the degree of the electron’s spatial localization increases with the passage of time if the electron is being accelerated. Zh. éksp. Teor. Fiz. 113, 841–864 (March 1998)     

Dirac particle in the presence of a plane waveand constant magnetic fields: path integral approach

The Green function (GF) related to the problem of a Dirac particle interacting with a plane wave and constant magnetic fields is calculated in the framework of a path integral via the Alexandrou et al. formalism according to the so-called global projection. As a calculation tool, we introduce two identities (constraints) into this formalism; their main role is the reduction of the dimension of the integral and the emergence in a natural way of some classical paths and, due to the existence of a constant electromagnetic field, we have used the technique of fluctuations. Hence the calculation of the GF is reduced to a known Gaussian integral plus a contribution from the effective classical action.Received: 22 January 2005, Revised: 16 May 2005, Published online: 9 August 2005     

Dirac particle with an anomalous magnetic moment in a circularly polarized wave and in constant longitudinal magnetic and electric fields

The wave function of an uncharged Dirac particle with an anomalous magnetic moment is calculated for the case where a circularly polarized wave propagating along constant magnetic and electric fields is present. Zh. éksp. Teor. Fiz. 111, 1190–1193 (April 1997)     

On the motion of a particle in a magnetic trap with a secondary electromagnetic field

The adiabatic approximation of motion in the plane perpendicular to the magnetic induction B and the averaged motion in the direction parallel to B are derived from the Hamiltonian transformed to natural coordinates. Certain conservative properties of the field are shown. The conditions derived therefrom for magnetic traps with a cusped field are given.The author would like to thank J. Váa for support and J. atlov and J. Teichmann for criticism of this work.     

Invariants of motion of a charge in the field of a circularly polarized wave

Six integrals of motion of a relativistic charge in the field of a transverse circularly polarized electromagnetic wave propagating with a phase velocity u > c are obtained from the solution of the Hamilton equations. These integrals form the basis of analysis of the trajectory of the charge depending on the phase of the wave in a stationary system of coordinates. The coordinates and phase are connected via elliptic functions.     

On the theory of the relativistic motion of a charged particle in the field of intense electromagnetic radiation

Averaged relativistic equations of motion of a charged particle in the field of intense electromagnetic radiation have been obtained in the geometrical optics approximation using the Bogoliubov method. Constraints are determined under which these equations are valid. Oscillating additions to the smoothed dynamical variables of the particle have been found; they are reduced to known expressions in the case of the circularly and linearly polarized plane waves. It has been shown that the expressions for the averaged relativistic force in both cases contain new additional small terms weakening its action. The known difference between the expressions for the ponderomotive force in the cases of circularly and linearly polarized waves has been confirmed.     

Production of a pair by a polarized photon in a uniform constant electromagnetic field

The total probability of production of an electron-positron pair by a polarized photon in a constant uniform electromagnetic field of an arbitrary configuration is determined using the imaginary part of the diagonalized polarization operator. Approximate expressions are derived for this probability in four ranges of photon energy. In the high-energy range, the corrections to the standard semiclassical approximation are calculated. In the range of intermediate energies, in which this approximation is inapplicable, the probability of the process is calculated using the steepest descent method. It is shown that in the range of photon energies higher than the pair production threshold in a magnetic field, a weak electric field removes root divergences in the probability of production of the particles at the Landau levels. For relatively low photon energies, a low-energy approximation is developed. At such energies, the effect of the electric field on the process is decisive, while the effect of the magnetic field is associated with its interaction with the magnetic moment of the particles being produced. Such an interaction is manifested, in particular, in the difference in the probabilities of production of a pair by an external field for scalar and spinor particles.     

Translational motion of domain walls in a strong magnetic field circularly polarized in the basal plane of a uniaxial ferromagnet

A substantially nonlinear theory is developed for the translational motion of domain walls (DWs) in ferromagnets with large easy-axis anisotropy under the influence of a strong magnetic field circularly polarized in the basal plane of the ferromagnet. This theory is a generalization of the well-known theories of DW drift that are limited to an approximation quadratic in the field magnitude. The analytical results are confirmed by computer simulation performed on the basis of the Landau-Lifshitz equations.     

Generation of circularly polarized photons by relativistic electrons moving in a crystal

The relativistic-electron (relativistic-positron) acceleration arising in its scattering on the potential of a crystal atomic string is highly anisotropic, which causes polarization of accompanying radiation. The possibility of developing an efficient source of circularly polarized photons by using electrons or positrons of energies attainable at many operating accelerators is demonstrated and analyzed.     

Coherent quantum states of a relativistic particle in an electromagnetic plane wave and a parallel magnetic field

We analyze the solutions of the Klein–Gordon and Dirac equations describing a charged particle in an electromagnetic plane wave combined with a magnetic field parallel to the direction of propagation of the wave. It is shown that the Klein–Gordon equation admits coherent states as solutions, while the corresponding solutions of the Dirac equation are superpositions of coherent and displaced-number states. Particular attention is paid to the resonant case in which the motion of the particle is unbounded.