The behavior of electromagnetic fields in nonlinear media has been a topical problem since the discovery of materials with a nonlinearity of electromagnetic properties. The problem of finding exact solutions for the source-excited nonlinear waves in curvilinear coordinates has been regarded as unsolvable for a long time. In this work, we present the first solution of this type for a cylindrically symmetric field excited by a pulsed current filament in a nondispersive medium that is simultaneously inhomogeneous and nonlinear. Assuming that the medium has a power-law permittivity profile in the linear regime and lacks a center of inversion, we derive an exact solution for the electromagnetic field excited by a current filament in such a medium and discuss the properties of this solution.

Excitation of electromagnetic waves by spatially bounded given electric currents in the presence of an axially magnetized cylindrical plasma column surrounded by free space is studied. A rigorous solution for the total field comprising both the discrete and continuous parts of the spatial spectrum of the excited waves is found. Using the obtained field representation, an expression for the impedance of a loop antenna is derived and the contributions of guided and unguided modes of the column to the antenna impedance are determined for the whistler frequency range. Conditions have been revealed under which the real part of the antenna impedance is dominated by the contribution of guided waves. It is shown that when allowance for relatively small collisional losses in the plasma results in division of the guided whistler waves into weakly and strongly damped modes with significantly different field structures, appreciable redistribution of the antenna-launched power among the excited modes takes place. The results obtained are useful for clarification of the power-absorption mechanisms of whistler-range waves in a cylindrical magnetoplasma.

Guided propagation of waves in the whistler frequency range is studied in a collisional cylindrical plasma. A rigorous, full-wave approach is used to analyse the dispersion properties, damping constants and field distributions of whistler modes guided by an axially magnetized plasma column. Conditions are revealed under which weakly and strongly damped modes with significantly different field distributions can co-exist in such a waveguide in the presence of electron collisions. We show that the features of these modes are determined by the relative contribution of small-scale quasi-electrostatic waves to the total modal fields. This contribution is found to depend essentially on the electron collision frequency in the plasma. The results obtained are useful for clarification of the absorption mechanisms of whistler-range waves in a bounded plasma.

UDC 533.951We study the guided propagation of whistler waves along cylindrical ducts with enhanced density in a collisional magnetoplasma. It is shown that under certain conditions, the presence of comparatively small dissipative losses due to electron collisions in a plasma medium can lead to significant changes in the dispersion characteristics and field structures of whistler modes guided by such ducts compared with the case of a collisionless plasma. We present the results of numerical calculations showing such changes in the properties of whistler modes.

The energy-flow structure during the resonance scattering of a normally incident plane electromagnetic Hwave by a gyrotropic cylinder is studied. The main attention is focused on the bifurcations of the time-averaged Poynting vector field at the surface and volume plasmon resonances in the case where the cylinder is aligned with a gyrotropy axis. The behaviour of the Poynting vector field in this case is compared with that observed during the scattering by an isotropic cylinder, and significant differences in the energy-flow structures in the two cases are revealed. Conditions are found under which the maximum magnitude of the Poynting vector at the boundary of a gyrotropic cylinder turns out to be much greater than that at the boundary of an isotropic scatterer of the same shape and size.

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We study multiple scattering of electromagnetic waves by an array of parallel gyrotropic circular rods and show that such an array can exhibit fairly unusual scattering properties and provide, under certain conditions, a giant enhancement of the scattered field. Among the scattering patterns of such an array at its resonant frequencies, the most interesting is the distribution of the total field in the form of a perfect self-similar structure of chessboard type. The scattering characteristics of the array are found to be essentially determined by the resonant properties of its gyrotropic elements and cannot be realized for arrays of nongyrotropic rods. It is expected that the results obtained can lead to a wide variety of practical applications.

Abstract-The scattering of an obliquely incident H-polarized plane electromagnetic wave by a magnetized plasma column is studied. It is assumed that the column is located in free space and aligned with an external static magnetic field. The emphasis is placed on the case where the angular frequency of the incident wave coincides with one of the surface-or volume-plasmon resonance frequencies of the column. The spatial structures of the field and energy flow patterns in the near zone of the column are analyzed, and the location of the regions with a greatly enhanced magnitude of the timeaveraged Poynting vector is determined. It is shown that the sign reversal of the longitudinal energy-flow component that is parallel to the column axis can occur when passing across the boundary between the inner region of the column and the surrounding medium.