Vol 61, No 6 (2018)

We analyze the integral parameters of resonant interaction of relativistic electrons in the Earth’s radiation belts with electromagnetic ion–cyclotron waves. The analysis is based on numerical simulations. Wave packets of finite length with varying frequency and various amplitude profiles propagating from the equator are considered. The roles of three nonlinear interaction regimes, analyzed in the first part of our paper [1] for single particle trajectories, are compared. It is shown that interaction characteristics depend stronger on the electron energy and wave packet position for the wave packet with Gaussian amplitude profile than for the wave packet with constant amplitude. For the wave packet with Gaussian amplitude profile, the directed and diffusive transfer of particles in the phase space are comparable, while for the wave packet with constant amplitude the mean change in the equatorial pitch angle can be considerably (a factor of 3 to 5) greater than the standard deviation. The most significant decrease in the equatorial pitch angle and the largest fraction of the corresponding particles are obtained for particles with energies of about 1 MeV for the wave packet close to the equator. The fraction of particles which can be scattered into the loss cone after a single pass through the wave packet is 1.0–1.7%.

We present the results of numerical modeling of decameter radio-wave propagation on a weakly oblique Vasilsursk—Nizhny Novgorod path under conditions of traveling ionospheric disturbances. A comparison is made with the chirp sounding data obtained in winter with an average solar activity. The direction–velocity characteristics of the wave-like disturbances are determined. It is shown that in the daytime, in a quiet magnetic environment, medium-scale wave-like disturbances of the electron density with sizes about 100 km, a period of 15 min, and relative amplitude δ ≈ 0.1 can be responsible for the crescent traces on the ionograms. The wave-like disturbances propagate at a velocity of 110 m/s at the angle β ≈ −45° to the horizon with the wave vector oriented predominantly in the east–west direction.

We obtain the quadratically bimodular equation of state for a rod with cracks on the basis of a model of the crack as an elastic contact of rough surfaces of solids. The perturbation method is used to theoretically study the propagation and interaction of collinear longitudinal elastic (strong low-frequency and weak high-frequency) waves in such media. Expressions for the amplitudes of the secondary waves, namely, the second and the fourth harmonics of the strong wave, the second harmonic of the weak wave, and the combination-frequency waves are obtained.

We present a method for electrodynamic analysis of a microstrip antenna on a substrate made of a chiral metamaterial. Singular integral representations of the components of the electric field radiated by such an antenna are presented. A singular integral equation with the Cauchy singularity is obtained, which allows determining the function of the current-density distribution over the antenna surface. The dependences of the magnitude and phase of the electric-field components on the coordinates and the radiation patterns of the antenna are calculated. It is shown that the electromagnetic waves radiated by such an antenna have the elliptical polarization.