A. F. Kharshiladze

Solar-terrestrial storms of October 2003. 2. Five-phase dynamics of the substorm of October 28–30

The assumption that a solar-heliospheric storm has five phases is formulated based on the storm that occurred in October 2003. The first phase: slow (between solar rotations) convergent motions of photospheric sources of large-scale open solar fields (LOFs) with generation of active regions (ARs) between these fields. The second phase: magnetic energy pumping with adjustment of zero lines of the photospheric magnetic field in AR to the configuration of the LOF sector (subsector) boundaries. The third phase: AR destabilization with ordering of the complex of sporadic phenomena near ARs parallel to the zero line and fragments of the nearest LOF boundary. The fourth phase: propagation of disturbances in the near-Sun space with ordering relative to the LOF boundaries. The fifth phase: propagation of a coronal mass ejection (CME) in the inner heliosphere in the case when the axial axis of a magnetic cloud in CME is parallel to the LOF boundary and to the zero line in AR. Original results of LOF modeling and a number of substantial results of the known advanced studies of individual aspects of this storm are used to justify this dynamics as applied to the storm of October 28–30. Specific contents and features of each storm phases are presented. The specific feature of the first phase, responsible for the storm space-time scales and intensity, consisted in the displacement of the entire LOF negative magnetic flux (∼5 × 1022 μs) from the north pole to the south with flowing around a midlatitude obstacle and with zonal convergent motions of LOF. The assumption of the AR configuration adjustment (the second phase) and ordering of disturbances (the third–five phases) during this storm near the subsector boundary between LOFs of identical polarity has been confirmed. It is noted that the pulse phase of the AR 0486 flare, coronal waves, and dimmings along the subsector boundary and the southwestern LOF “dam” joining ARs 0486 and 0484 (superposition of the third and fourth phases) originated almost simultaneously. The two-component disturbance structure is confirmed: halo-type CME with the axis along the LOF subsector boundary and a bright local ejection of magnetic plasma from the region above the southwestern LOF dam.

Calculation of the interplanetary magnetic field based on its value in the solar photosphere

The difficulties associated with calculating the parameters of the interplanetary magnetic field (IMF) from solar magnetic data have been considered. All conventional calculation patterns and available input databases have been analyzed from a unified standpoint. It has been shown that these assumptions and limitations cannot affect the general structure and dependence on cycle of solar and interplanetary data. At the same time, the measured solar field values are underestimated as a result of the magnetograph signal saturation effect. It has been shown that the correction should depend on the heliocentric observation latitude and cycle phase. The correction method responsible for good agreement between the calculated and measured values has been proposed. The created database makes it possible to quantitatively calculate the magnetic fields in the solar wind near the Earth.

Dynamics of Solar Activity and Anomalous Weather in Summer 2010: 1. Sector Boundaries: Anticyclone Formation and Destruction

A close synoptic relationship has been found, on the one hand, between the sector structure of the solar and interplanetary magnetic fields and, on the other hand, the structure of tropospheric parameters (the near-Earth pressure and temperature) in Central Russia during an anomalously hot anticyclonic weather in June–August 2010. It has been stated that the Earth crossed the magnetic sector boundaries in full agreement with the boundaries of meteorological parameters, structuring the formation, stabilization, and decay dynamics of anticyclones according to observations performed at IZMIRAN (Troitsk, φ = 55°, λ = 37°).

MHD nature of the origination, dynamics, geoeffectiveness, and disappearance of the four-sector structure of the solar magnetic field during the cycle 23 decline phase

The MHD nature of the origination, dynamics, geoeffectiveness, and disappearance of the four-sector structure of the solar magnetic field during the cycle 23 decline phase has been established. A prolonged ordered MHD process including the chain of the interrelated phenomena (unknown before this study), which begin and end in one of the main zones of active longitudes and are responsible for the above nature of the four-sector structure, has been detected as a result of the simulation of the large-scale open solar magnetic field and an analysis of the dynamics of this field fluxes. These phenomena are as follows: the extreme concentration of the photospheric field sources of the same sign in the zone of active longitudes; blocking of regular differential rotation by these sources; origination of a nonstationary MHD disturbance in the form of a four-sector structure, traveling in the direction of solar rotation at a nearly Alfvén velocity; upset of blocking, displacement of blocking sources from the zone, and their shearing motion relative to a traveling MHD disturbance; deceleration and dissipation of a four-sector MHD disturbance; and reconstruction of a bisector structure. The interactions during this process, which lasted from May 2004 to December 2005, were accompanied by the generation of an ordered succession of heliospheric and solar-terrestrial disturbances including the series of nine extrastorms that were observed from July 2004 to September 2005 and were the last storms in the finished cycle 23 of solar activity.

Multiparameter Computations of Solar Wind Characteristics in the Near-Earth Space from the Data on the Solar Magnetic Field

The solar wind parameters were analyzed using the concept which is being developed by the authors and assumes the existence of several systems of magnetic fields of different scales on the Sun. It was demonstrated that the simplest model with one source surface and a radial expansion does not describe the characteristics of the quiet solar wind adequately. Different magnetic field subsystems on the Sun affect the characteristics of the solar wind plasma in a different way, even changing the sign of correlation. New multiparameter schemes were developed to compute the velocity and the magnetic field components of the solar wind. The radial component of the magnetic field in the solar corona and the tilt of the heliospheric current sheet, which determines the degree of divergence of field lines in the heliosphere, were taken into account when calculating the magnetic field in the solar wind. Both the divergence of field lines in the corona and the strength of the solar magnetic field are allowed for in calculating the solar wind speed. The suggested schemes provide a considerably higher computation accuracy than that given by commonly used one-parameter models.

Intersector disbalance of the large-scale open solar magnetic field fluxes, active and passive boundaries, and solar-terrestrial extrastorms

The dynamics (from rotation to rotation) of the absolute values of the large-scale open solar magnetic field fluxes in the four-sector field structure has been considered for the first time, using CRs 2032–2035 in July–October 2005 as examples. An important role of the ratio of the fluxes at the eastern and western sector boundaries (ΦE/ΦW) is confirmed. As in the cases of the two-sector structure, ΦE/ΦW > 1 is typical of active rigidly corotating boundaries with intense sunspot formation, flares, and interplanetary and geomagnetic disturbances. A remarkable property of the considered structure was the presence of a rapidly increasing flux in an initially narrow sector and the flux interaction with a stable rigidly corotating sector in the zone of the main active longitudes, which caused an unexpectedly strong geoeffective long-range action of flares near the corresponding active boundary.

Solar-terrestrial extrastorm of August 22–25, 2005. I. Solar sources

The solar-terrestrial extrastorm of August 22–25, 2005, has been considered in the context of the cyclic dynamics and structure of the large-scale open solar magnetic field and has been rated among the other extrastorms of cycle 23. It has been established that the storm under discussion was one of the last six extrastorms in the cycle that occurred during the specific third interval of the declining phase—the period of quasirigidly corotating four-sector structure. Inside this structure, we have revealed convergent motions of the photospheric sources of open fields, the active sector boundary, and the formation of a narrow longitudinal sector with the activity complex responsible for the set of four extrastorms of January–September 2005. It is shown that all extrastorms were accompanied by significant variations (up to 1021 μs) of the open field flux Φ. The storm of August 22–25 was accompanied by an increase in the magnetic flux Φ in the corresponding sector (with a doublet of solar flares) and a fast expansion of the sector to the dimensions at the beginning of this interval (September 2004).

Sector Spherical Harmonic Analysis of the Solar Magnetic Field

The theory of sector harmonic analysis has been developed as applied to the specific conditions of the solar magnetic field. A computer program has been developed. The possibilities of the program are illustrated in an analysis of a large-scale open solar field “singularity” observed on August 11, 2004, using MDI magnetometer data.

Dynamics of the large-scale open solar magnetic field and its specific features in the zone of the main active longitudes in 2006–2012

The dynamics of the absolute global values (Φ) of the large-scale open solar magnetic field (LOSMF) fluxes at an interval of one solar rotation in 2006–2012 has been studied based on the Wilcox Solar Observatory data and using the ISOPAK original package for modeling the solar magnetic field. The reference points and the duration of the final quasi-biennial interval in cycle 23 (January 2006–May 2007; 17 months) and the phases of the cycle 24 minimum (May 2007–November 2009; 30 months), growth (November 2009–May 2012; 30 months), and the beginning of the maximum (May 2012–January 2013) have been determined. It has been indicated that the absolute values (Φ) decreased sharply at the beginning of the minimum, growth, and the maximum phases to ∼(2, 1.25, 0.75) × 1022 Mx, respectively. During the entire minimum phase, LOSMF corotated super-quasi-rigidly westward in the direction of solar rotation; at the beginning of the growth phase, this field started corotating mostly eastward. The LOSMF polarity reversal in the current cycle 24 started in May–June 2012 (CR 2123–2124), when fields of southern polarity rushed from the Sun’s southern hemisphere toward the north. The statement that the solar cycle is a continuous series of quasi-biennial LOSMF intervals is confirmed. In particular, the minimum and growth phases are characterized by opposite LOSMF rotation directions, i.e., super-quasi-rigid corotation (twisting) and detwisting, with identical duration at least in cycle 24.

Comparison of the sector and conventional spherical harmonic analyses of the solar magnetic field on the photosphere, source surface, and in the Earth’s orbit on July 10–20, 2004

The results of a spherical harmonic analysis and a sector spherical harmonic analysis of the solar magnetic field on the photosphere, source surface, and in the Earth’s orbit on July 10–20, 2004, were compared. It was found that the field values according to a sector harmonic analysis are an order of magnitude as large as the same values according to a spherical harmonic analysis and differ in the configuration. A twocomponent magnetic field structure was revealed: short-range sources are better described by a sector spherical harmonic analysis; long-range sources are better described by a spherical harmonic analysis. This is caused by the different depths of the occurrence of sources below the photosphere.