Nonlinear dynamics of charged particles interacting with combined ac-dc electromagnetic fields

A nonlinear Lorenz model describing interactions between charged particles and combined ac-dc electromagnetic fields is studied for various combinations of frequencies, field strengths and relative angle (θ) between the ac and dc magnetic fields. Strong directional effects on the magnitude and location of resonant particle motion are observed when θ is varied and the regular resonance windows in the aligned field (θ = 0) and linear version of the model studied previously by Durney etaal., break up to form irregular and less well pronounced regions of large and small particle displacements when nonlinearities are taken into account. The length of time takne to achieve resonant behaviour also becomes larger and more variable when nonlinearities are present. The possible relevance of these effects to interactions between electromagnetic fields and biological media is briefly discussed.     

Relativistic charged particles in the field of an electromagnetic plane wave in a medium

Solutions of the Klein-Gordon and Dirac equation for a charged particle in the field of an electromagnetic plane wave in a medium with a constant refractive index n are discussed. Generally, for n² < 1, spontaneous pair creation from the vacuum, and for n² > 1, energy bands are observed. The interplay of Compton and Cherenkov scattering is discussed. Some doubts are formulated as to the physical relevance of calculating pair creation in a homogeneous electric field as it is usually done.     

Attenuation of electromagnetic wave propagation in sandstorms incorporating charged sand particles

A theoretical approach for predicting the attenuation of microwave propagation in sandstorms is presented, with electric charges generated on the sand grains taken into account. It is found that the effect of electric charges distributed partially on the sand surface is notable. The calculated attenuation is in good agreement with that measured in certain conditions. The distribution of electric charges on the surface of sand grains, which is not easy to measure, can be approximately determined by measuring the attenuation value of electromagnetic waves. Some effects of sand radius, dielectric permittivity, frequency of electromagnetic wave, and visibility of sandstorms on the attenuation are also discussed quantitatively. Finally, a new electric parameter is introduced to describe the roles of scattering, absorption and effect of charges in attenuation.     

Induced radiation by charged particles moving in a plane electromagnetic wave

It is shown that when a charged particle moving in the field of a plane electromagnetic wave is subjected to another electromagnetic wave, incident at some angle with respect to the first, induced radiation and absorption occur. Under certain conditions the induced radiation predominates over the absorption.Translated from Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 50–53, September, 1969.The authors thank professor I. M. Ternov for useful discussions.     

Stimulated Brillouin scattering of an electromagnetic wave in weakly magnetized plasma with variably charged dust particles

We have investigated analytically the stimulated Brillouin scattering (SBS) of an electromagnetic wave in non-dissipative weakly magnetized plasma in the presence of dust particles with variable charge.     

Confinement of charged particles by an electromagnetic wave leaving the region of a strong gravitational field

The interaction of a charged particle in vacuum with a circularly polarized wave leaving the region of a strong static gravitational field in the direction of a magnetostatic field is considered. It turns out that this combination of fields forms, generally speaking, two capture regions (CR₁ and CR₂) on the phase cylinder of the particle. The evolution of these regions is determined by the gravitational field. The influence of the gravitational field on the rigidity of confinement of the particle in one of these regions (CR₁) is investigated. It is shown that the rigidity of confinement of particles with relatively high energies may increase toward the periphery of the gravitational field. The possibility of particle escape by the wave is demonstrated for particles whose initial energy is insufficient to leave the gravitational field region in the absence of the wave. In this case, the particle is trapped by the wave in CR₁ and subsequently confined. The mechanism of trapping the particle is discussed. Taganrog State Radio-Engineering University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 3–10, June, 2000.     

Trapping of charged particles by transverse electromagnetic waves

An estimate is made of the maximum number of resonant particles interacting with a transverse plane electromagnetic wave. This estimate is based on the distribution function, in terms of integrals characterizing the motion of particles in a wave. The values found here for proton fluxes accelerated by an amplitude-modulated wave in the solar corona agree with those measured during sporadic radioemission bursts.     

On the propagation of a paraxial beam of charged particles in an external electromagnetic field

A small-angle approximation method as applied to a curvilinear beam of relativistic particles in mutually orthogonal uniform magnetic and nonuniform electric fields is elaborated. Analytical solutions to the paraxial equation for curvilinear beams of charged particles are obtained.     

Formation dynamics of jumps in systems of charged particles

The results of numerical studies of the dynamics of two similarly charged particles in an external electric field are presented. The formation of “jumps” (i.e., spontaneous changes in the positions) of the particles in a stable quasi-equilibrium state of the system has been analyzed in detail. Both dynamical and structural properties of the systems being modeled have been found to change significantly with rising particle temperature near some critical coupling parameter.     

Channeling and electromagnetic radiation of relativistic charged particles in metal-organic frameworks

We have developed the theory of electromagnetic interaction of relativistic charged particles with metal-organic frameworks (MOFs). The electrostatic potential and electron number density distribution in MOFs were calculated using the most accurate data for the atomic form factors. Peculiarities of axial channeling of fast charged particles and various types of electromagnetic radiation from relativistic particles has been discussed.     

Coherent electromagnetic radiation of a modulated beam of charged particles

The intensity of electromagnetic radiation produced by a modulated beam of charged particles is estimated. The coherence effect is due to the modulation, i.e. to periodicity in the particles distribution.     

Nonlinear reflection of an electromagnetic wave from bismuth with supersonic drift of carriers

It has been shown experimentally that the supersonic Hall drift of carriers in bismuth in magnetic fields H = 20?100 kOe stimulates nonlinear reflection of 9.2 GHz electromagnetic wave: the second harmonic power increases by a factor of 10² to 10³. According to the model proposed this effect is related to amplification by the supersonic drift of the hypersonic wave generated at the surface of the crystal.     

Limit velocity of charged particles in a constant electromagnetic field under friction

It is shown that when a particle moves in a constant electromagnetic field and is subjected to frictional forces its velocity to ds to a limit independent of the initial conditions. A limit velocity exists as well for the motion of relativistic particles in constant electric fields.     

The manipulation of charged particles into and out of electromagnetic traps

The manipulation of charged particles into and out of Paul and Penning ion traps is discussed in terms of the phase space volume of a particle collection and its manipulation. It is shown that such traps can have very large usable phase space volumes but that the shape of such volumes is severely mismatched to that of a typical ion beam from a separator or storage ring. Possible injection schemes are presented as well as some aspects of ion cooling within the trap and subsequent ion extraction. Possible applications to the manipulation of antiproton beams from LEAR and 10 MeV/A highly-stripped heavy ions at GSI are discussed.     

On the electromagnetic emission from charged test particles in a five-dimensional spacetime

We study the motion of charged particles radially falling in a class of static and electromagnetic-free, five-dimensional Kaluza–Klein backgrounds. Particle dynamics in such spacetimes is explored by an approach à la Papapetrou. The electromagnetic radiation emitted by these particles is studied, outlining the new features emerging in the spectra for the five-dimensional case. A comparison with the dynamics in the four-dimensional counterpart, i.e. the Schwarzschild background, is performed.     

Motion of the charged particles off the equatorial plane of a Kerr black hole in an electromagnetic field

Charged particle orbits off the equatorial plane of a Kerr black hole in an external electromagnetic field is studied, both for dipole as well as uniform magnetic field. Particles are found to get trapped by the magnetic field if the initial value of the parallel velocity is small. Bending of the field lines in the vicinity of the hole and the consequent trapping of the particles in an otherwise uniform magnetic field indicates the significance of general relativistic effects in such cases.