Том 56, № 6 (2018)

Within the axisymmetric MHD model of the solar wind, the magnetic field of the Sun has been analyzed in two phases of the solar cycle: the minimum activity, when the dipole magnetic field dominates and the maximum activity, when the quadrupole field predominates. It has been shown that during the period of maximum solar activity, the heliospheric current sheet acquires a conical shape and shifts to high latitudes up to 30° above the ecliptic plane. In the opposite hemisphere, at the same latitudes, a second current sheet of conical shape with an azimuth current of the opposite direction is established. It has been shown that the profiles of the main characteristics of the solar wind become steeper with distance from the Sun, and their amplitudes decrease, in this case, for the quadrupole field, the dependences of the main characteristics of the solar wind are more complex. A comparison of the results of the model with averaged characteristics of the solar wind shows a good match between the observed values and model parameters.

This paper analyzes the correlation between planetary indices of geomagnetic activity Dst, ap, and AE and the values of coupling functions, calculated from data on plasma and magnetic field parameters during four types of solar wind (SW) streams: the regions of interaction of streams with different velocities (co-rotating interaction region—CIR), interplanetary manifestations of coronal mass ejections ICMEs (MC and Ejecta), and the Sheath compression regions in front of MC and Ejecta. To select SW types, we used data from ftp://ftp.iki.rssi.ru/pub/omni/ for 1995–2016, in which 744 CIR, 118 MC, 501 Sheath, and 843 Ejectaevents were identified. The coupling functions were calculated based on the OMNI data base. The analysis has shown low values of correlation coefficients (R < 0.5) between the coupling functions and Dst index for all SW types. For the ap and AE indices, a rather strong correlation with coupling functions (0.6 < R < 0.82) was obtained for all SW types. The geoeffectiveness of coupling functions, estimated from the values of linear regression coefficients, has the highest values for the ap index for the Sheath and MC SW types. For the auroral AE index, the highest values of coupling function efficiencies were obtained for the CIR and Ejecta SW types.

The results of studies of proton flux dynamics of the ring current and magnetic field in the middle of radiation belts during two strong magnetic storms in 2015 (March 17–18, 2015 and June 22–23, 2015) with a close amplitude of Dst-variations (∣Dst_max∣ ~ 200 nT) are presented. An analysis of the experimental data obtained on board two space vehicles named Van Allen Probes (earlier: Radiation Belt Storm Probes, RBSP), located at an orbit close to equatorial is performed. Modeling of the ring current and magnetic field in the frames of the paraboloid model of Earth’s magnetosphere А2000 is conducted. Confirmation of the existence of a mechanism for ring current development and, respectively, geomagnetic storm under the action of a strong pulse of solar-wind pressure is obtained as a result of comparative analysis of ring current dynamics and the magnetic field in the middle of radiation belts during the main phases of two storms in 2015. It is found that during the magnetic storm of June 22–23, 2015, the development of the ring current during the main phase continued despite the northward turn of the interplanetary magnetic field (IMF) and the following period with positive B_z in the solar wind. The effect observed during June 22–23, 2015 is explained by the intensification of storm ring current due to a long and powerful pulse of the solar wind pressure that led to a nonadiabatic transport of the ring current particles to lower L shells.

Within the self-consistent hybrid model based on the quasi-adiabatic approximation of the proton dynamics, a fine structure of strong current sheets (SCSs) in the solar wind has been investigated, including the heliospheric current sheet. The motion of electrons is fast and considered in the Boltzmann approximation. The simulation results have been shown that the SCS profiles have a multiscale enclosed structure with a narrow central current sheet that is enclosed in a wider sheet, similar to the heliospheric current sheet surrounded by the plasma sheet. The features of the SCS structure are determined by the relative contributions of the current of demagnetized protons in serpentine orbits and drift currents of electrons. The model predicts and describes the properties of SCSs observed by spacecraft. It has been shown that the multiscale structure of current sheets is an inherent intrinsic property of current sheets in the solar wind.

Temporal variations in the relative number of failed rocket launches in Russia (Soviet Union) and the United States have been compared to reveal that these variations are antipersistent. The accident rates of rocket and space equipment launches have been analyzed as a function of the level and phase of solar activity cycle. The relative number of failed launches in Russia (Soviet Union) and the United States for the growth phase of solar activity has been shown to exceed the number for the phase of solar activity decline, although no clear correlation between solar activity and the number of failed launches has been detected.