Motion of a particle in a static magnetic field and in the field of a electromagnetic plane wave

The solutions of the equations of motion of a charged particle in an external electromagnetic field consisting of a superposition of a constant uniform magnetic field and the field of a circularly polarized electromagnetic plane wave are presented as solutions of the Cauchy problem. The resonance case is studied. Zh. Tekh. Fiz. 67, 94–99 (February 1997)     

Quantum-electrodynamic processes in a strong nonclassical electromagnetic field

Quantum-electrodynamic processes that take place in the presence of a squeezed electromagnetic field are discussed. Integral formulas are derived that make it possible to express the probability of any process in a squeezed electromagnetic field in terms of the probability of the same process in a classical electromagnetic field. The main laws that govern processes of first order in the fine-structure constant as functions of the number of photons involved and the quantum fluctuations are examined. Tunneling formulas for the probability of a photon producing an electron-positron pair in a strong squeezed field are derived. Also, resonant electron-electron scattering is examined and the scattering cross section as a function of the statistical properties of the field (the way the field has been squeezed) is investigated. It is found that the quantum fluctuations of the squeezed electromagnetic field give rise to an increase in the scattering cross section, with the probability of the process in a phase-squeezed electromagnetic field always being higher than the probability of the process in an amplitude-squeezed electromagnetic field. Zh. éksp. Teor. Fiz. 112, 1543–1556 (November 1997)     

Fabry-Perot cavity in the field of a gravitational wave

The structure of the electromagnetic field inside a laser cavity—a gravitational-wave detector—is studied. The properties of the spatial and temporal phases of the standing electromagnetic wave are discussed in detail and the corrections appearing in the electric field of the wave as a result of the action of gravitational radiation on the optical system are determined. Zh. éksp. Teor. Fiz. 113, 398–408 (February 1998)     

Multiple ionization of a Thomas-Fermi cluster by a strong electromagnetic field

We develop a new model of a Thomas-Fermi cluster that describes the distribution of electrons in alkaline clusters with many atoms. We examine the classical multiple ionization of such a cluster by a strong electromagnetic field. Finally, we calculate the degree of ionization as a function of the field strength. Zh. éksp. Teor. Fiz. 115, 2014–2019 (June 1999)     

The magnetic field of Langmuir oscillations

The small-scale quasistationary magnetic field appearing in a plasma exhibiting plasma oscillations is considered. It is shown that this magnetic field is capable of leading to dissipation of the electromagnetic waves propagating in the plasma. Zh. Tekh. Fiz. 67, 140–141 (June 1997)     

High-frequency phenomena in organic conductors in a magnetic field

The propagation of electromagnetic waves in organic layered conductors with metallic conductance and a quasi-two-dimensional electron energy spectrum of arbitrary form is studied theoretically. The depth of penetration of the electromagnetic field into the conductor is found, and it is discovered to be sensitive to the polarization of the incident wave. This is done for an arbitrarily oriented (with respect to the layers) magnetic field so strong that the radius of curvature of the electron path is much smaller than the electron’s mean free path. It is established that studying these effects in experiments can reveal in detail the shape and dimensions of the Fermi surface and the relaxation properties of the conduction electrons. Zh. éksp. Teor. Fiz. 114, 676–686 (August 1998)     

Four-photon polarization spectroscopy of water in a millimeter-wave radiation field

Resonance (frequency 1.4 cm⁽⁻¹) changes induced in the four-photon optical spectrum of water by a millimeter-wave electromagnetic field are observed experimentally. Comparison with the spectrum of ice in the range 0‒2 cm⁽¹ shows that the action of such a field is of a structure-forming character. Pis’ma Zh. éksp. Teor. Fiz. 68, No. 4, 266–268 (25 August 1998)     

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)     

Derivation of the vacuum longitudinal fieldB (3) from the Dirac equation of the electron in the electromagnetic field

By solving the Diras equation for the motion of an electron (c) in the circularly polarized electromagnetic field it is shown that the intrinsic electron spin forms an interaction Hamiltonian with a time independent fieldB ⁽³⁾ of electromagnetic radiation in the vacuum. In the same way as intrinsic spin is a fundamental property of the electron,B ⁽³⁾ is therefore a fundamental and intrinsic property of the vacuum electromagnetic field.     

Ionization self-channeling of modulated plasma-wave beams in a magnetic field

The dynamics of ionization self-channeling of modulated beams of plasma waves forming a solitary plasma-wave channel in an external magnetic field is investigated. It is shown that electromagnetic wave processes at the modulation frequencies of the ionizing radiation can be excited in the background plasma and in the channel. Zh. éksp. Teor. Fiz. 113, 1289–1298 (April 1998)     

Exact solution of the vectorial field structure of a light beam

An alternative way of finding electromagnetic solutions based on the closest solution defined by Martinez-Herrero et al. [J. Opt. Soc. Am. A 18, 1678 (2001)] has been proposed. It is found that by identifying the components of closest solution as the components of the planewave spectrum of realistic fields at z = 0, an exact solution of the electromagnetic fields satisfying the Maxwell equations can also be obtained. This solution is applied to calculate the fields of a radially polarized Laguerre-Gaussian laser beam. It shows that although both formalisms are correct ways of finding electromagnetic solutions, as the beam waist size is less than a laser wavelength, the longitudinal electric field near the focus obtained from our solution can be significantly larger than that by Martinez-Herrero et al.     

On the Dirac equation with anomalous magnetic moment term in a beam of electromagnetic wave

The object of the paper is to obtain the solution of the Dirac equation with the Pauli-term in an electromagnetic field depending on the single variable (ct -nr) along the directionn.     

On the transverse distribution of a resonance field excited by a Gaussian electromagnetic beam on the critical surface of a radially nonuniform plasma sphere

The transverse distribution of the resonance field excited by a Gaussian electromagnetic field on the critical surface of a radially nonuniform plasma sphere is studied. Analytical expressions are obtained for this distribution. It is shown that when a laser beam is focused in front of or behind a spherical target, identical values of the integrated resonance coefficient can correspond to substantially different (in width) distributions of the resonance field over the spherical critical surface. Zh. Tekh. Fiz. 67, 125–128 (October 1997)     

Propagation of a beam of gamma rays in the field of a monochromatic laser wave

The head-on propagation of a beam of γ grays through the field of a laser wave is investigated. The optical properties of the laser wave (as a medium) are described by the dielectric tensor. The refractive indices are determined, and the polarization characteristics of electromagnetic normal modes capable of propagating in such a medium are investigated. Relations are derived to describe the variation of the initial polarization and intensity of a γ-ray beam as it propagates in a laser field. The influence of laser intensity on the investigated process is discussed. Zh. éksp. Teor. Fiz. 112, 2016–2029 (December 1997)     

Mass operator of an axion in a crossed field

The dominant one-loop electron contribution to the mass operator of an axion in a crossed field in the asymptotic limits of the parameters q ²/m _e ² and is calculated. The corresponding electromagnetic mass of the axion is compared with the quantum-chromodynamic mass due to mixing with π. Expressions are derived for the probability of pair creation a→e ⁺ e ⁻, and the fundamental conclusion is reached that refractive effects are present in the propagation of an axion in an external electromagnetic field. Zh. éksp. Teor. Fiz. 113, 1558–1565 (May 1998)     

Anisotropic momentum transfer in low-dimensional electron systems in a magnetic field

In low-dimensional systems with an asymmetric quantizing potential, an asymmetric electron energy spectrum ε(p)≠ε(−p), where p is the electron momentum, arises in the presence of a magnetic field. A consequence of such an energy spectrum is that momentum transfer to the electron system in mutually opposite directions in the presence of an external perturbation is different. Therefore, in the presence of a standing electromagnetic wave momentum is transferred from the wave to the electrons, which gives rise to a new type of electromotive force. Pis’ma Zh. éksp. Teor. Fiz. 66, No. 8, 551–555 (25 October 1997)     

Effectiveness of the repulsion of electromagnetic coils with strength and magnetic field limitations

Mechanical power units utilizing electromagnetic interaction between coils are generally distinguished by compactness and ease of control. A coil-repulsion drive configuration is preferable for increasing the efficiency of such a device. One of the main limitations in choosing the parameters of stressed electromagnetic systems is mechanical strength. The application of superconducting coils has a number of additional limitations, for example, on the maximum magnetic field strength in the cross section of the coils. The problems of optimizing the dimensions of the electromagnetic system of a power unit consisting of two identical, coaxial, annular coils of rectangular cross section with opposing currents are investigated with allowance for strength and magnetic field limitations. Zh. Tekh. Fiz. 67, 124–127 (May 1997)     

Ionization of a molecular hydrogen ion by a strong low-frequency electromagnetic field of laser radiation

Simple analytical expressions are obtained for the energy and angular distributions of outgoing electrons in ionization of a molecular hydrogen ion by a strong low-frequency electromagnetic field as well as for the ionization probabilities per unit time. The cases of linear and circular polarization of the laser radiation are studied. It is shown that in contrast to the case of the ionization of atoms oscillations appear in the energy spectra of the photoelectrons as a function of their kinetic energy. The well-known limits for the tunneling ionization probabilities for the hydrogen atom by a strong low-frequency alternating field are obtained in the case of large internuclear separations. Zh. é ksp. Teor. Fiz. 113, 583–592 (February 1998)     

Evolution of the width of the wave packet of a charged particle interacting with a quantum electromagnetic field

The path integral method is used to study the width of the wave packet of a relativistic charged particle interacting with a quantum electromagnetic field. A general expression is derived for the density distribution of a particle moving in arbitrary external potentials. An electron synchrotron with weak focusing is studied as a specific example, and the width of the wave packet of an electron moving in this accelerator is found. Zh. éksp. Teor. Fiz. 111, 1563–1578 (May 1997)     

Ionization of a two-electron atom in a strong electromagnetic field

A one-dimensional model of a helium atom in an intense field of a femtosecond electromagnetic pulse has been constructed using the Hartree technique. “Exact” calculations have been compared to the approximations of “frozen” and “passive” electrons. A nonmonotonic dependence of the single-electron ionization probability on the radiation intensity has been detected. Minima in the ionization probability are due to multiphoton resonances between different atomic states due to the dynamic Stark effect. We suggest that the ionization suppression is due to the interference stabilization in this case. Zh. éksp. Teor. Fiz. 112, 470–482 (August 1997)