The stable existence of 4 coronal holes on the solar surface is shown, which during two Carrington revolutions CR2081 and CR2082 emit four stable quasi-stationary SW (solar wind) flows towards the Earth. The position of the neutral line of the IMF (interplanetary magnetic field) CR 2081 and CR 2082 also remains stable. For quasi-stationary SW flows, the maximum velocity Vmax weakly depends on the corresponding magnetic field B at the moment of time, the value of which at the Earth's orbit is in the range of ≈ (2–8) nT. For sporadic SW, Vmax increases more than twice, with B (IMF strength modulus) values in the range of large values from ≈ 15 nT to ≈ 52 nT. Thus, measuring the value of “B” at the moment of registration, the value of Vmax allows us to understand in advance whether the observed SW flow is quasi-stationary or sporadic. Predict whether the observed SW flow is of the quasi-stationary or sporadic type.

We have shown that diamagnetic structures (DSs), which form the basis of the slow quasistationary solar wind (SW), are observed in Earth's orbit as a sequence of DSs of various scales. The analysis of this phenomenon indicates that diamagnetic plasmoids in SW, whose concept was introduced by Karlsson in 2015, are identical to small-scale DSs. We have found that the impact of a sequence of DSs in the slow SW on Earth's magnetosphere causes an increase in geomagnetic activity. Isolated DSs generate short-term magnetic disturbances whose duration is approximately equal to the DS duration. Hence, a sequence of DSs can cause sawtooth substorms. We emphasize that the interaction of DS in the slow SW under northward interplanetary magnetic field can be associated with penetration of DS high-density plasma into the magnetosphere.

The two limb CMEs considered in this paper differ from the cases of type 1 and type 2 CMEs studied earlier in [1]. At the same time, they noticeably differ from each other in the nature of their formation, which remains not completely clear. It is unusual in the formation of the April 29, 2014 CME that its appearance is associated with the eruption of only a larger part of the magnetic rope. A specific feature of the February 11, 2014 CME is the fact that it already has a very high velocity of motion near the surface of the Sun - about 1300 km/s, which rapidly decreases as it moves away from the Sun. But they are united by the fact that they both have an extremely low final speed of the CME - no more than 350 km / s. The answer to the question of what determines the formation of these slow CMEs (ICMEs for short) is important for further studies of the dynamics and nature of CMEs.

Based on a detailed study of the sporadic solar wind (SW) recorded at 1a.u. December 15-16, 2013, as well as 13 selected sporadic SW streams for the period 1996-2012, within the structure ICME, a region referred to as a "magnetic cavity" ("magnetic cavity") is distinguishеd. It is characterized and determined by a high degree of anticorrelation between the plasma density N and the IMF modulus B. At its front boundary, N sharply drops and B increases, and at the rear boundary, on the contrary, N sharply increases and B falls. Inside the cavity, the duration of which can be in the interval ≈ 1-30 hours N and B change little. According to measurements on the TNE and TNV satellites located in the daytime and nighttime magnetospheres, respectively, it is shown that the effect of the cavity on the bow shock wave (NESH) leads to a sharp drop in the geomagnetic field modulus along the duration corresponding to the duration of the magnetic cavity and to a sharp shift of the GOAW towards the Sun.

Analysis of seven near-limb coronal mass ejections (CMEs) has shown that at distances R<1.4R from the center of the Sun CMEs according to their formation can be divided into two types: type 1 CMEs and type 2 CMEs. In the case of type 1 CMEs, the frontal structure (FS) is formed by processes occurring in FS itself, which is the outer shell of the magnetic flux rope. As for type 2 CMEs, EP-CME, internal arched structures erupt, explosively expand, capture and accelerate the more distant arched structures, which merge to form the frontal structure of the type 2 CMEs.

The study examined a chain of phenomena from the Sun to the Earth, which allows to study the mechanism of geoeffectiveness of eruptive prominences propagating from the Sun inside the CME (coronal mass ejections). An eruptive prominence ejected into the solar wind moves with its speed towards the Earth in the form of a DSEP (diamagnetic structure of an eruptive prominence). The contact of the DSEP with the magnetosphere leads to its compression and the passage of the DSEP substance into the magnetosphere. The duration of a magnetospheric disturbance in the form of polar auroras on the dayside, a global amplification of current systems, an increase in charged particle fluxes in the radiation belts, and the generation of irregular pulsations of the Pi2-3 type is determined by the duration of the DSEP. A diagram of the geoeffectiveness of the DSEP has been constructed. The resulting scheme is confirmed by statistical studies of the DSEP in different years of solar activity.

It is shown that a diamagnetic structure (DS) of the slow solar wind (SW), the source of which on the Sun was a chain of streamers, arrived at Earth’s orbit on December 22, 2015. It interacted with Earth’s magnetosphere under conditions when the northward Bz component of the interplanetary magnetic field (IMF) remained for a long time in preceding undisturbed SW. The interaction and a sharp change in the direction of Bz to the south generated an isolated substorm whose duration depends on the duration of interaction with the DS. The substorm began at midday with the passage of the DS into the magnetosphere and spread to the east. All phases of the substorm — growth, expansion, and recovery — were observed for two hours. Variations in the SW and IMF parameters are shown to coincide for the isolated substorm whose energy source was the slow solar wind DS, and a trigger was the abrupt change in the direction of the vertical IMF component from north to south. The coincidence is justified by statistical generalizations of the same parameters in 40 % of cases of long-term observations of individual substorms whose trigger was a change in Bz direction.

The structure of the solar wind plasma flow downstream of the ramp of the interplanetary shock is studied based on the BMSW plasma spectrometer installed onboard the SPEKTR-R spacecraft. Particular attention is paid to the overshoot region, where correlated oscillations of the ion flux and magnetic field, which decaying with distance from the ramp, are observed. They are formed by two populations of ions: the inflowing solar wind and the beam of reflected ions. Based on an analysis of 26 crossings of interplanetary shock fronts, in which overshoots were observed in the value of the ion flux and the magnetic field, it is shown that overshoots form not only in supercritical shock, but also in those with Mach numbers that are less than or approach the value of the first critical Mach number. It is found that the formation and value of the overshoot amplitude in the structure of the shock front are significantly influenced by the angle between the normal to the shock front and the magnetic field vector ahead of the front, the Mach number, and the magnetic and plasma compression at the wave front. It is established that the oscillation wavelength determined from the magnetic field measurements onboard the WIND spacecraft, on average, coincides with the oscillation wavelength determined from the ion flux on the SPEKTR-R spacecraft, while the spatial scales of the oscillation-damping regions can greatly differ.

Показано, что на орбите Земли 22.12.2015 г. взаимодействие диамагнитной структуры (ДС) медленного солнечного ветра с магнитосферой после продолжительной северной ориентации Bz генерирует изолированную суббурю, длительность которой определяется длительностью ДС. Суббуря начинается в околополуденные часы прохождением ДС в магнитосферу и распространяется к востоку. В течение двух часов наблюдаются все фазы суббури – подготовительная, взрывная и восстановительная. Протоны ДС, генерируясь в области источника, достигают орбиты Земли и, взаимодействуя с частицами радиационных поясов, вызывают генерацию колебаний IPDP в околополуденные часы в большом широтном диапазоне.

The structure of quasiperpendicular interplanetary (IP) shock fronts was studied based on the data from the BMSW plasma spectrometer, installed onboard the SPEKTR-R spacecraft, supplemented by magnetic field measurements on the WIND. Special attention was paid to periodic growths (overshoots) in the value of the ion flux relative to their mean values outside the ramp. A comparison of plasma overshoot was performed with the overshoot in the magnetic field, with the Mach number, and with the β parameter. Based on the analysis of 26 crossings of IP shocks, in which the overshoots in the ion flux and magnetic field value were observed, it was shown that the value of the magnetic field overshoot is, on the average, less than a similar value in the solar wind’s ion flux, which is associated with different time resolution of measurements. The ion flux overshoot value is found to grow with the growth of the Mach number. It is shown that overshoots are formed not only in the supercritical shocks, but also in those with Mach numbers that are less than the value of the first critical Mach number. It is also found that the estimates of the coherent downstream oscillations of the ion flux and magnetic field good correlate with the convected ion gyroradius. This work was supported by the Russian Foundation for Basic Research, grant no. 19-02-00177.

We have analyzed the fast coronal mass ejection (CME) that occurred on February 25, 2014. The analysis is based on images taken in the 131, 211, 304, and 1700 Å UV channels of the SDO/AIA instrument and from observations obtained in the Hα line (6562.8 Å) with the telescopes of the Teide and Big Bear Observatories. The February 25, 2014 CME is associated with the ejection and subsequent explosive expansion of the magnetic flux rope, which appeared near the solar surface presumably due to the tether-cutting magnetic reconnection. The impulse of full pressure (thermal plus magnetic) resulting from such an “explosion” acts on the overlying coronal arcades, causing them to merge and form an accelerated moving frontal structure of the CME. This pressure impulse also generates a blast collisional shock wave ahead of the CME, whose velocity decreases rapidly with distance. At large distances R>7R₀ (R₀ is the solar radius) from the center of the Sun in front of the CME, a shock wave of another type is formed — a “piston” collisional shock wave whose velocity varies little with distance. At R≥15R₀, there is a transition from a collisional to a collisionless shock wave.

The structure of subcritical interplanetary shocks was studied using high time resolution from the BMSW plasma instrument onboard the Spektr-R satellite and MFI magnetometer measurements from WIND. Ion scales of the ramp and wavelength of precursor waves were obtained and compared with results of the bow shock structure study. The comparison of precursor wavelengths, determined experimentally with those determined from dispersion relation for low-Mach, low-beta shocks has showed similar results. This confirms the assumption that the dispersion of oblique magnetosonic waves is the determining factor in the formation of upstream wave trains. On the base of the case study it was shown that damped downstream oscillations of density, velocity, temperature may be generated by the interaction of the inflowing solar wind ions with the reflected gyrating ions inside the ramp. A sequence of six wave trains of magnetosonic whistlers has been observed upstream the ramp of subcritical oblique IP shock. The amplitude of oscillations inside the trains decreased with increasing distance from the ramp. The possible energy dissipation mechanism within the shock front is discussed.

The results presented in this review reflect the fundamentals of the modern understanding of the nature of the structure of the slow solar wind (SW) along the entire length from the Sun to the Earth's orbit. It is known that the source of the slow quasi-stationary SW on the Sun is the belt and the chains of coronal streamers The streamer belt encircles the entire Sun as a wave-like surface (skirt), representing a sequence of pairs of rays with increased brightness (plasma density) or two lines of rays located close to each other. Neutral line of the radial component of the solar global magnetic field goes along the belt between the rays of each of these pairs. The streamer belt extends in the heliosphere is as the heliospheric plasma sheet (HPS). Detailed analysis of data from Wind and IMP-8 satellites showed that HPS sections on the Earth orbit are registered as a sequence of diamagnetic tubes with high density plasma and low interplanetary magnetic field. They represent an extension of rays with increased brightness of the streamer belt near the Sun. Their angular size remains the same over the entire way from the Sun to the Earth's orbit. Each HPS diamagnetic tube has a fine internal structure on several scales, or fractality. In other words, diamagnetic tube is a set of nested diamagnetic tubes, whose angular size can vary by almost two orders of magnitude. These sequences of diamagnetic tubes that form the base of slow SW on the Earth's orbit has a more general name — diamagnetic structures (DS). In the final part of this article, a comparative analysis of several events was made, based on the results of this review. He made it possible to find out the morphology and nature of the origin of the new term “diamagnetic plasmoids” SW (local amplifications of plasma density), which appeared in several articles published during 2012–2018. The analysis carried out at the end of this article, for the first time, showed that the diamagnetic plasmoids SW are the small-scale component of the fractal diamagnetic structures of the slow SW, considered in this review.

The event on January 27, 2012 is an example of the features of the dynamics of formation of a shock, excited by a fast coronal mass ejection (CME) at a velocity higher than 2000 km/s, are investigated. The following data were used: (a) images of the Sun in the UV channel of 13.1 nm from the AIA instrument at distances of 1.0–1.4 solar radii from the Sun’s center, (b) the images of the white corona from the LASCO C2 and C3 coronographs at R ≈ 2.1–30 solar radii. Investigations indicated the validity of regularities, established earlier for the cases of relatively slow CMEs (at velocities <1500 km/s): (1) The shock front is formed, when the velocity of a leading part of a CME relative to the undisturbed solar wind becomes greater than the local Alfven velocity of wind, which corresponds to the phenomenon of “transition through the sound velocity” for magnetized plasma. (2) The change in the width of a shock front and, accordingly, in the energy dissipation mechanism occurs in a shock front from a “collisional” one, at distances from the Sun’s center lower than 10 solar radii, to a “collisionless” one, at distances greater than ten solar radii. During the event of January 27, 2012, it was possible to investigate in more detail the process of transition from the collisional to collisionless shock front. It was found that the longitudinal length of a shock front, excited by a fast CME at distances lower than 6 solar radii, increased almost 10 times as compared to a slower CME. One of the main causes for this increase, along with a high velocity, is the fact that the motion of CME has occurred in the plane of the belt of coronal streamers. It is concluded that, at distances lower than 6 solar radii, the shock front structure ahead of the CME is of “parallel” type; that is, the angle between the vector of an undisturbed magnetic field and the normal to the front was close to 0°.

We present an analysis of the event near the east limb, SOL2014-03-06T09:23, in which a pseudo coronal mass ejection (CME) was detected by the Large Angle and Spectrometric Coronagraph (LASCO) C2 instrument and indicated as “Poor Event; Only C2” in the Solar and Heliospheric Observatory (SOHO) LASCO CME Catalog. The analysis was performed based on two main methods: 1) investigation of the difference brightness profiles along specific directions in the solar corona using the EUV observations by the Atmospheric Imaging Assembly (AIA) instrument onboard the Solar Dynamics Observatory (SDO); 2) investigation of the spatially-resolved observations of the type II radio bursts made with the Nançay Radioheliograph. Based on the analysis performed we argue that the observed pseudo-CME could be a blast wave caused by impulsive flare energy release in the low corona. We also argue that, in the limited height range of ${\approx}\,0.2 \mathrm{R_{\odot }}\,\mbox{--}\,0.5 \mathrm{R}_{\odot}$, the front of this blast wave could steepen into a shock front.

The purpose of this study is to generalize the results of investigation of the magnetosphere response to two types of diamagnetic structures. Type 1 is related to sporadic SW, type 2 - to the quasi-stationary “slow” solar wind (SW). First, we consider the Type 1 of diamagnetic structures that are connected with sporadic SW, whose source on the Sun is coronal mass ejections (СМЕs). Near the rear side of a magnetic cloud, one often observes a thin magnetic rope with a high-density plasma. This rope is ejected by a filament (or an eruptive prominence) from the solar surface. The rope is a diamagnetic structure with the same properties, as those of a magnetic tube. Such tubes are diamagnetic, i.e., a diamagnetic current flows on their surface. This current decreases the magnetic field inside the pipe and increases the latter outside. The total pressure (magnetic plus gas-kinetic) is approximately constant inside and outside the tube. Tubes keep their angular size during propagation from the Sun to the Earth, i.e., they are quasi-static. Type 2 represents magnetic tubes (in general case, magnetic ropes) whose sources on the Sun are the streamer belt and the streamer chains or pseudo-streamers. In the Earth orbit, the SW diamagnetic structures are detected by the presence of anti-correlation between the SW proton density and the magnitude of interplanetary magnetic field (IMF). The analysis showed that an interaction of diamagnetic structures (DSs) with the Earth magnetosphere generates substorm-like (sawtooth) magnetic disturbances in the nightside magnetosphere. The disturbances are different from classical substorms because of the absence of the growth phase and of the breakup. The diamagnetic structures related to the quasi-stationary slow SW cause a global modulation of the magnetic activity and of the ionospheric currents with a period close to the period of the variations in the SW plasma density and in the IMF strength inside the diamagnetic structure.