Distinguishing features of a series of solar proton event (SPE) catalogs for the 20th–24th cycles of solar activity are described. The results of a comparative analysis of the 23rd and 24th cycles of solar activity performed according to the data of a series of SPE catalogs are presented. The opportunities provided by SPE catalogs for studying space weather factors, such as the dynamics of solar activity, the structure and state of the interplanetary medium, and the Earth’s magnetosphere are discussed.

Homogeneous series of solar cosmic-ray events for four solar-activity cycles against the background of decreased activity in cycles 23 and 24 are considered. The number of solar cosmic-ray events with energies above 10 MeV decreased insignificantly, while the number of ground-level enhancements in comparison between cycles 23 and 24 decreased by eight times. It is shown that the average contribution of flares to the generation of ground-level enhancements decreased from cycle 23 to cycle 24 by three times, and the average contribution of coronal mass ejections decreased by five times; the average contribution of flares to the generation of solar cosmic rays with energy >10 MeV decreased by 1.3 times, and the average contribution of coronal mass ejections increased by 1.4 times.

Type-II radio emission often accompanies events in solar cosmic rays and is an indicator of the propagation of a shock wave in the solar corona. Conversely, the shock wave associated with coronal mass ejections plays an important role in the acceleration of solar protons. Both of these phenomena can occur unaccompanied by solar cosmic rays, while not all solar cosmic ray events are accompanied by type-II radio emission. The statistical relationships between these phenomena are considered based on the catalogs of solar proton events for the 23rd and 24th solar-activity cycles. It is shown that the events of solar cosmic rays accompanied by type-II radio emissions are among the most powerful in terms of both particle characteristics and source characteristics.

Solar proton events are compared using the Catalogue of Solar Proton Events of the 24th Cycle of Solar Activity and solar events with long-duration high-energy gamma radiation based on measurements at the Fermi gamma-ray telescope. High-energy γ-quanta are mainly the product of the decay of π о -mesons during the interaction of high-energy protons on the Sun. Sources of gamma-ray flares not accompanied by solar protons are located in the eastern hemisphere of the Sun, and the associated coronal ejections do not move toward the Earth. Solar protons from such sources are not recorded by the terrestrial observer.

Logachev catalog data for solar cycle 23 has been used to study the dependence of measured increases in solar cosmic rays (SCRs) on solar perturbations. The efficiency of recording the SCR increases, driven by proton acceleration in the corona, on Earth and in its vicinity is shown to depend on power of a solar flare that created a shock wave and on position of the flare on the solar disk. As the particle flux moves along the heliolongitude away from the parent flare, the acceleration efficiency decreases, i.e. the maximum energy of the accelerated particles and their intensity at equal energy decrease. As a result, at a certain distance along a heliolongitude from the parent solar flare, the solar proton flux intensity decreases to the galactic background, and there is no SCR increase detected.

The paper discusses the dynamics of the outer electron belt, adiabatic and nonadiabatic mechanisms of replenishment and losses of energetic electrons. Under undisturbed conditions, the outer electron belt gradually empties: in the inner magnetosphere due to electron precipitation in the atmosphere and in the quasi-trapping region due to losses at the magnetopause because drift shells of electrons are not closed there. The latter process does not occur in normal years due to the masking replenishment by freshly accelerated particles, but in years of extremely low activity it leads to a significant decrease in the electron population of the belt. During the magnetic storm main phase, the first reason for the decrease in the electron flux intensity is the adiabatic cooling associated with conservation of adiabatic invariants and complemented by precipitation of electrons into the atmosphere and their dropout at the magnetopause. Electron flux increases involve EB electron injection by the induction electric field of substorm activation and by the large-scale solar wind electric field, with pitch energy diffusion along with adiabatic heating in the recovery phase. The rate of electron flux recovery after a storm is determined by the ratio of nonadiabatic increases and losses; hence the electron flux represents a continuous series from low to very high values. The combination of these processes determines the individual character of radiation belt development during each magnetic storm and the behavior of the belt in the quiet time.

Solar proton events possess a wide variety of features that reflect the conditions of solar proton acceleration and propagation. Relevant investigations rely on statistical methods that make it possible to classify events with the aim of obtaining deeper insight into physical processes leading to the generation of solar cosmic rays. In classifying events in power, the intensity of particles with energy above 10MeV at the maximum of the event time profile or the fluence of particles throughout the event time is usually used. A new parameter, E (qm), that characterizes the proton event power and which is some kind of approximation of the maximum energy of accelerated particles is analyzed in the present study. Correlations of E (qm) with properties of x-ray flares on the Sun and with the velocity of coronal mass ejections are examined.

The results from observing Jovian electrons in the vicinity of the Earth are discussed. Variations in Jovian electron flows are observed during 14 rotations of the Sun in 2007–2008. The results are analyzed by assuming the existence of magnetic traps in the space between the Sun and Jupiter that are filled with electrons near Jupiter, and are then registered when the traps pass by the Earth. The average period of variation in the Jovian electron flow during the 14 solar rotations is 26.2 days instead of the expected synodic period of the Sun–Earth system equal to 27.3 days. An explanation for this phenomenon is proposed.

Variations in the flux of Jovian electrons near the Earth in two synodic cycles of the Earth–Jupiter system, in 1974–1975 and 2007–2008, are considered. In the 1974–1975 cycle, Jovian electrons were observed by IMP-8 during 13 successive solar rotations; electrons were observed by SOHO during 14 solar rotations during the 2007–2008 cycle. The fluxes of these electrons in each solar revolution experienced variations with a characteristic time scale of ~27 d , with the maximum flux near the middle of the rotation. The mean period of the variations does not coincide with the synodic period for the Sun–Earth system, equal to 27.3 d . The mean variation periods for the electron fluxes were 26.8 d in 1974–1975 and 26.1 d in 2007–2008. The detected variations are interpreted as reflecting variations in the structure of the solar wind speed and associated magnetic traps, the confinement time of the electrons in thesemagnetic traps, and the influence of the relative positions of the Earth and Jupiter in space.

The ring current is conventionally considered responsible for the shift of the boundary of solar proton penetration into the inner Earth's magnetosphere during magnetic storms. The cases of a boundary shift were observed in some works on the dark side before the onset of a magnetic storm, i.e., at positive values of the Dst index. In this work, this type of shift of the penetration boundary is considered in detail with two storms as examples. It is shown that the corresponding distortion of the magnetosphere configuration is induced by an increase in the solar wind pressure during the initial phase of a magnetic storm. The current induced in this case on the magnetopause is closed by a current in the equator plane, which changes the configuration of the dark side of the inner magnetosphere, weakens the magnetic field, and allows solar protons to penetrate the inner magnetosphere. The significant difference in the positions of the penetration boundary and the boundary found from models of the magnetosphere magnetic field can be explained by insufficient consideration of closing currents.

During the years of high and moderate activity, the energetic flux of electrons at geostationary region increases compensated by the losses and as a result, the overall level of the population persists. The transitions from high to low intensity and back by 3-4 orders of magnitude are fast within hours and caused by the magnetic disturbances, storms and substorms.During the years of the low activity, the balance of increases and losses is violated; the whole flux of electrons is reduced. Particularly noticeable was the devastation of the outer belt during the minimum of 2009-2010 years. The slow type of decreases became most active. The transition from the fast type to the slow type of decreases was created by the prolonged periods of the low substorm activity. The slow type of intensity decreases is mostly probable caused by the losses on the magnetopause. (C) 2017 COSPAR. Published by Elsevier Ltd. All rights reserved.

A brief description of the structure of the magnetosphere-that is, permanent and temporary radiation belts, plasmasphere, and plasma layers-is presented. It is shown that the results of measurements of properties of energetic particles and plasma are sufficient for such a description. The outer night slope of the electron radiation belt is singled out as an individual domain where energetic particles do not complete a closedmagnetic drift and where substorm processes develop. This region, which is referred to as an auroralmagnetosphere, is often erroneously treated as only part of the radiation belt. In different domains of the magnetosphere, different mechanisms of the precipitation of particles causing Earth's airglow in the form of auroras act independently. The properties and origin of these precipitated particles are different, and it is unreasonable to consider them as a unified formation-a ring or an auroral oval. It is equally erroneous to treat the oval as a kind of formation, a structure, or a domain of the magnetosphere and not as a manifestation of processes that proceed in domains.

Many works have been devoted to studying the boundaries of the penetration of solar protons into the Earth's magnetosphere. This work first considers the dynamics of not only the boundary, but the latitudinal profiles of penetration in general depending on the energy and local time of measurement according to the data of the low-altitude CORONAS-F satellite. When flying through the polar cap, the isotropic pitch-angle distribution of protons leads to the equality of the recorded precipitating flux and the proton flux in the interplanetary space. Beginning at a particular latitude, the proton flux begins to drop and, over time, reaches the level of the background of galactic cosmic rays. The latitudinal profile measured in this manner on the night side reaches the bending point when the Larmor radius of the proton becomes comparable with the radius of the curvature of the line of force; after partial trapping, the flux of precipitating protons successively drops. The protons are transferred to the day side by the magnetic drift and, unlike the night profile, the character of the day profile depends on the configuration of the entire magnetosphere. The character of latitudinal profiles has been studied depending on the local time and energy of the particles, which enabled the features of the magnetosphere deformation to be evaluated at certain times of magnetic storms.