Том 60, № 8 (2018)

We generalize the equations, which describe the backward-wave oscillator regime in the magnetized plasma in the presence of a jump (“step”) in the velocity distribution function of energetic charged particles, to the case of an arbitrary direction of the wave relative to an external magnetic field and an arbitrary wave mode. The dependence of instability threshold on the angle χ between the wave vector k and the external magnetic field B₀ for whistler-mode waves and a slow extraordinary wave (Z-mode) is determined.

Two modern radars for diagnosis of the ionosphere by the radio-wave backscattering method, namely, the Irkutsk incoherent scatter radar at VHF (IISR, 154–162 MHz) and the Ekaterinburg coherent radar at HF (EKB, 8–20 MHz) are operated at the Institute of Solar-Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences (ISTP SB RAS). The paper analyzes the results of joint observations of strong scattering (radio aurora) on June 8, 2015. To determine the geographical position of the radio aurora, we developed original methods that take into account both the features of the radio-wave propagation and the features of the radar antenna systems. It is shown that there are areas where the spatial position of the HF and VHF radio aurora can coincide. This permits using the radars as a single complex for diagnosis of the characteristics of small-scale high-latitude irregularities in the ionospheric E and F layers. A comparative analysis of the characteristics and temporal dynamics of the radio-aurora region in the HF and VHF ranges is performed. Using the DMSP satellite data, it has been shown that the radio aurora dynamics during this experiment with the EKB radar can be related with the spatial dynamics of the localized area with high electric field, which moves from high to equatorial latitudes. It is found that due to the broader field of view, radio aurora at the HF radar was stably observed 6–12 min earlier than at the VHF radar. This permits using the EKB radar data for prediction of the radio-aurora detection by the IISR radar.

We consider the problem of radiation from a traveling-wave antenna in a warm electron plasma which moves along a strong magnetic field at a constant velocity. To describe the electromagnetic properties of the plasma, we use the diagonal tensor of dielectric permittivity, which is calculated for a magnetized plasma with the Maxwellian electron velocity distribution allowing for collisions of electrons with neutral molecules. The dispersion relation is analyzed numerically, and expressions for the field amplitudes in the wave zone are obtained. The radiation resistance of the antenna is calculated. It is shown that as the phase velocity of the traveling current wave in the antenna approaches the average velocity of the plasma motion, the radiation field decreases exponentially with distance from the source as a result of the efficient transfer of the wave energy to the plasma electrons due to collisionless interaction.

We estimate thermal aberrations in Cr:CdSe and Cr:ZnSe chalcogenide crystals exposed to continuous-wave electromagnetic radiation at a wavelength of 1907 nm. Using the SIMULIA Abaqus software suite, deformation of such materials during their heating due to absorption of part of the radiation is simulated numerically. On the basis of the obtained results, the focal distances of the lenses induced in crystalline media are calculated by the matrix optics method.