Vol 57, No 2 (2019)

The response of the total electron content (TEC) of Earth’s ionosphere to impulse geomagnetic disturbances, traveling convection vortices (TCVs), is considered in the paper. The data of networks of ground-based magnetometers in Canada and Greenland were used to reveal TCVs, whereas the TEC variations were obtained by processing the data of the IGS and UNAVCO receiving stations of the global positioning system (GPS). Ionospheric disturbances related to TCVs are detected. Using the station network makes it possible to estimate the dynamics of formation and velocity of propagation of the disturbance in space.

Data analysis of long-term multi-frequency monitoring of active galactic nucleus (AGN) AO 0235+164 in the millimeter wavelength range are presented. Using the harmonic analysis of observational data, the presence of orbital and precession periods in the binary system from supermassive black holes (SBHs) is determined: T_orb ≈ 2 years and T_pr ≈ 8 years. The indicated periods are in agreement with similar periods found for other bright AGNs. In the AO 0235+164 system, other combinations of periodic components are also determined, which are possibly related to the nutation period. According to observational data of the development of flare phenomena at different frequencies, a cross-correlation analysis was performed and the shift delays of the flare times occurring at different wavelengths were determined. It was confirmed, by analogy with other AGNs, an empirical relation, to which the delays of flux variations with a frequency are obeyed having the form of the inverse logarithmic dependence. The nature of the delays can indicate the internal character of the variability of AGN emission fluxes obtained at frequencies of the centimeter and millimeter wavelength ranges. The hypothesis of jet activity of AGNs is confirmed, in which plasma formation, moving from the sources of ejection, becomes optically thin consistently on ever longer waves. Decreasing delays between frequencies for the flare in 2015 compared to the previous flare in 2008–2009 indicates a possible configuration variation in AO 0235+164 associated with decreasing in the angle between ejections and the direction to the observer.

The quaternion equations of disturbed motion of an artificial Earth satellite (AES) in Earth’s gravitational field (with regard to its zonal, tesseral, and sectorial harmonics) are obtained in four-dimensional Kustaanheimo–Stiefel variables and in modified four-dimensional variables. In the latter variables the equations of satellite motion have a simpler and more symmetric structure, as compared to the equations of motion in the Kustaanheimo–Stiefel variables. The obtained equations are linear for undisturbed Keplerian motion and, in general, have the form of equations of motion of a disturbed four-dimensional oscillator. These equations, in contrast to classical equations, are regular (they do not contain specific points of singularity) for satellite motion in the central gravitational field of Earth under an effect of disturbing forces, the description of which does not contain negative, higher-than-first powers of the satellite distance to Earth’s center. In these equations, the basic variables are Kustaanheimo–Stiefel variables, or modified four-dimensional variables proposed by the author, as well as satellite motion energy and time. The new independent variable is associated with time by the differential relation containing the satellite distance to Earth’s center of mass. The equations are convenient for applying nonlinear mechanics methods and for high-precision numerical calculations. In the case of artificial satellite motion in Earth’s gravitational field, the description of which does not take into account the tesseral and sectorial harmonics, but takes into account its zonal harmonics, the first integrals of the equations of satellite motion are found, and the replacements of variables and transformations of these equations are proposed, which allowed one to get, for studying satellite motion, closed systems of differential equations of lower dimension, in particular, the system of equations of fourth and third orders.

The results of estimated calculations of fluxes of particles of the working fluid in peripheral regions from the axial direction of the jet of a magnetoplasmodynamic (MPD) thruster with an external magnetic field with a power of 100 kW as well as the results of measurements in laboratory conditions of reverse fluxes of Li particles from the thruster are presented. Return flow measurements were conducted using the quartz microbalance method. Calculations and measurements of particle fluxes indicate that their values do not exceed ~10^–8–10^–7 g cm^–2 s^–1.