Author name code: obridko ADS astronomy entries on 2022-09-14 author:"Obridko, Vladimir N." ------------------------------------------------------------------------ Title: Solar and stellar activity cycles - no synchronization with exoplanets Authors: Obridko, V. N.; Katsova, M. M.; Sokoloff, D. D. Bibcode: 2022MNRAS.516.1251O Altcode: 2022arXiv220806190O; 2022MNRAS.tmp.2179O Cyclic activity on the Sun and stars is primarily explained by the generation of the magnetic field by a dynamo mechanism, which converts the energy of the poloidal field into the energy of the toroidal component due to differential rotation . There is, however, an alternative point of view, which explains the field generation by the gravitational influence of the planetary system and, first of all, Jupiter. This hypothesis can be verified by comparing the characteristics of exoplanets with the activity variations on their associated stars. We have performed such a comparison and have drawn a negative conclusion. No relationship between the gravitational influence of the exoplanets and cycle of the host star could be found in any of the cases considered. Moreover, there are reasons to believe that a strong gravitational influence may completely eliminate cyclic variation in stellar activity. Title: Solar and Stellar Flares: Frequency, Active Regions, and Stellar Dynamo Authors: Katsova, M. M.; Obridko, V. N.; Sokoloff, D. D.; Livshits, I. M. Bibcode: 2022ApJ...936...49K Altcode: 2022arXiv220803994K We demonstrate that for weak flares the dependence of their frequency occurrence on spottedness can be rather weak. The fact is that such flares can occur in both small and large active regions. At the same time, powerful large flares of classes M and X occur much more often in large active regions. In energy estimates, the mean magnetic field in starspots can also be assumed to be equal to the mean field in the sunspot umbra. So the effective mean magnetic field is 900 Mx cm-2 in sunspots and 2000 Mx cm-2 in starspots. Moreover, the height of the energy storage cannot be strictly proportional to A 1/2. For stars, the fitting factor is an order of magnitude smaller. The analysis of the occurrence rate of powerful solar X-ray flares of class M and X and superflares on stars shows that, with allowance for the difference in the spottedness and compactness of active regions, both sets can be described by a single model. Thus, the problem of superflares on stars and their absence on the Sun is reduced to the problem of the difference in the effectiveness of the dynamo mechanisms. Title: Clarifying physical properties of magnetic fields in sunspots Authors: Obridko, Vladimir; Sokoloff, Dmitry; Livshits, Ilya; Shelting, Bertha; Katsova, Maria Bibcode: 2022cosp...44.1133O Altcode: From the very beginning and long afterwards, the number and area of sunspots were determined visually from solar images based on their photometric properties. Nowadays, we are using photo and numerical records. There is no doubt, however, that the main factor determining the very existence of a sunspot is the magnetic field. Nevertheless, a definition of the sunspot boundary in terms of the magnetic field is still absent in scientific literature. Here, we suggest such a definition based on SDO/HMI observations. We demonstrate that the radial magnetic field component at the outer boundary of the penumbra is about 550 Mx/cm2 independent of the sunspot area and the maximum magnetic field in the umbra. The mean magnetic field intensity in sunspots grows slightly as the sunspot area increases up to 500-1000 m.v.h. and may reach about 900 Mx/cm2 . The mean field in umbrae is around 2000 Mx/cm2 The total magnetic flux weakly depends on the maximum field strength in a sunspot and is determined by the spottedness, i.e., the sunspot number and the total sunspot area; however, the relation between the total flux and the sunspot area is substantially nonlinear. We suggest an explicit parametrization for this relation. The contribution of the magnetic flux associated with sunspots to the total magnetic flux is small, not achieving more than 20% even at the maximum of the solar activity. Acknowledgements VNO, MMK, DDS acknowledge the support of Ministry of Science and Higher Education of the Russian Federation under the grant 075-15-2020-780. Title: Automated detection of solar magnetic tornadoes based on computer vision methods Authors: Vorobev, Dmitrii; Obridko, Vladimir; Khabarova, Olga; Blumenau, Mark; Fridman, Mikhail Bibcode: 2022cosp...44.1135V Altcode: We show a possibility of automated detection of solar magnetic tornadoes, using the classic computer vision and deep learning methods. We define magnetic tornadoes, independently of their origin, as magneto-plasma objects in the solar corona in which a magnetic field is twisted. Typically, a whole magnetic tornado rotates resembling tornadoes in the terrestrial atmosphere. Meanwhile, there are also tornadoes in which only plasma flows upward along the magnetic field spiral but the whole structure just shakes. The lack of identified structures is one of many problems that prevent studying the physics of magnetic tornadoes and the processes associated with them. In particular, the filamentary rotating structures are well detectable only at the limb, while one can only make suppositions about their presence at the solar disk. Our method relies on analyzing SDO/AIA images at wavelengths 171 \AA, 193 \AA, 211 \AA, 304 \AA, to which several different algorithms are applied, namely, convolutional and recurrent neural networks and optical flow calculations. The new technique combines several approaches that are established in various fields of data analysis. Such an approach allows detecting the structures with sufficient accuracy and recall. For training objects, we used magnetic tornadoes previously described in the literature [e.g., Wedemeyer et al. 2013, ApJ; Mghebrishvili et al. 2015 ApJ] as well as newfound ones. Our method made it possible to detect those structures, as well as to reveal previously unknown magnetic tornadoes. Title: What determines the number of current sheets at 1 AU? Authors: Sagitov, Timofey; Obridko, Vladimir; Khabarova, Olga; Kislov, Roman Bibcode: 2022cosp...44.1507S Altcode: A statistical analysis of the multi-year database of current sheets identified at 1 au. (csdb.izmiran.ru) shows that the number of current sheets per unit of time varies by tens or even hundreds of times. Current sheets are more often recorded during the arrival of turbulent plasma flows associated with ICME sheaths and corotating/stream interaction regions (CIRs/SIRs). We have previously found that the number of current sheets per day is determined by the sum of densities of the kinetic energy and the thermal energy of the solar wind (Khabarova et al. 2021). This fact raises the following question: Do the current sheets heat the plasma around them or an increase in the current sheet number is caused by an increase in the temperature? With both theories having ardent supporters, we provide additional facts for consideration in this debate, analysing statistical properties of current sheets. We compare the number of identified current sheets per day with the effective multipole index (Obridko et al, 2021), the number of sunspots and the solar wind temperature. We show that long-term variations in the current sheet rate have a solar origin, while short-term variations come from local processes in the solar wind. We underline the fact that a good correlation between the occurrence of current sheets and the increased temperature does not prove the fact of heating of the solar wind by current sheets. Khabarova, O., Sagitov, T., Kislov, R., & Li, G. Automated identification of current sheets—A new tool to study turbulence and intermittency in the solar wind. Journal of Geophysical Research: Space Physics, 126, e2020JA029099. (2021). https://doi.org/10.1029/2020JA029099 Obridko, V.N., Sokoloff, D. D., Pipin, V.V., Shibalva, A. S., Livshits, I. M. Zonal harmonics of solar magnetic field for solar cycle forecast, Journal of Atmospheric and Solar-Terrestrial Physics, 2021, 225, 105743, DOI: https://doi.org/10.1016/j.jastp.2021.105743 Title: Solar and stellar flares: occurrence frequency, properties of active regions and efficiency of stellar dynamo Authors: Obridko, Vladimir; Sokoloff, Dmitry; Livshits, Ilya; Katsova, Maria Bibcode: 2022cosp...44.1138O Altcode: It was demonstrated that for weak flares the dependence on spottedness can be rather weak. The fact is that such flares can occur both in small and large active regions. At the same time, powerful large flares of classes M and X occur much more often in large active regions. It should be noted that the procedures used to determine the spot areas on the Sun and stars are essentially different. In the former case, the observer directly calculates the area of each spot from the full image of the Sun and, then, sums up the values obtained. The penumbra is traditionally included in the spot area. For stars, a different procedure is used, which is based on the temperature difference between the star and the observed spot. This difference corresponds to the temperature difference between the spot umbra and the star. This means that, in fact, we find the total area of the umbra or, to be more precise, the area of a starspot can be considered coinciding with the area of the umbra. Therefore, in energy estimates, the mean magnetic field in starspots can also be assumed equal to the mean field in the sunspot umbra. So the effective mean magnetic field is ~900 Mx/cm^2 in sunspots and ~2000 Mx/cm^2 in starspots. K Moreover, the height of the energy storage cannot be strictly proportional to A^1/2. For stars, the fitting factor is an order of magnitude smaller. The analysis of the occurrence rate of powerful solar X-ray flares of class M and X and superflares on stars shows that, with allowance for the difference in the spottedness and compactness of active regions, both sets can be described by a single model. Thus, the problem of superflares on stars and their absence on the Sun is reduced to the problem of difference in the effectiveness of the dynamo mechanisms. Acknowledgements Authors acknowledge the support of Ministry of Science and Higher Education of the Russian Federation under the grant 075-15-2020-780. Title: A non-linear approach to predicting the amplitude and timing of the sunspot area in cycle 25 Authors: Chowdhury, Partha; Sarp, Volkan; Kilcik, Ali; Ray, Pratap Chandra; Rozelot, Jean-Pierre; Obridko, Vladimir N. Bibcode: 2022MNRAS.513.4152C Altcode: The sunspot cycle waxes and wanes over a period of about 11 years and modulates 'space weather'. Therefore, predicting the maximum amplitude of the solar cycle is an important goal for both solar physics and space weather. It is clear nowadays that cyclic variations of the Sun are non-linear processes, and thus the above-mentioned goal is difficult to reach with accuracy, albeit several methods currently exist to forecast both long-term and short-term variations. Solar cycle 25 has recently started and knowing the strength and timing of maximum of this cycle in advance is essential. In this study, a non-linear prediction algorithm, non-linear empirical dynamical modelling (EDM), is used to forecast the maximum amplitude and timing of the sunspot area of this cycle. This technique was tested on the last solar cycle 24 (Sarp et al. 2018) and the results obtained are in good agreement with observed values. Our study unveils that the maximum amplitude of the sunspot area of the whole solar disc will be 1606.49 ± 412.78 millionths of the solar hemispheric area (m.s.h.) and is expected to occur around 2025 March. We found that the predicted maximum sunspot areas in the Northern and Southern hemispheres are 731.39 ± 192.7 and 764.89 ± 195.39 m.s.h., respectively, with probable times of maxima around 2023 September and 2024 August, respectively. These results indicate that the strength of the sunspot area in solar cycle 25 will be weaker than or comparable with that in solar cycle 24. Such results are discussed and compared with other recent forecasts. Title: Study of the Magnetic Properties of Sunspot Umbrae Authors: Zagainova, Yu. S.; Fainshtein, V. G.; Obridko, V. N.; Rudenko, G. V. Bibcode: 2022ARep...66..116Z Altcode: The paper presents the results of the study of sunspots, obtained by the authors and other researchers in recent years. The results regarding the atmosphere above sunspot umbrae, based on the observational data in the spectral lines of the upper chromosphere and lower corona, are discussed. It is shown that individual parameters of the profile of these lines differ in leading and trailing sunspots. A hypothesis about the relationship between the parameters of the profiles of these spectral lines and the parameters of the magnetic field in sunspot umbrae is stated and tested. A comparative analysis of the magnetic properties of the umbrae of leading and trailing sunspots in active regions (ARs) without explosive processes (EPs, id est, formation of coronal mass ejection with solar flare) is carried out. For the analysis, only pairs of magnetically coupled (connected by magnetic field lines) leading and trailing sunspots were selected. It is shown that the values of a number of magnetic field parameters in sunspot umbrae and the character of the relationship between them depend on the type of the sunspots. In particular, in the umbrae of leading and trailing sunspots of close areas, the maximum and average magnitudes of the magnetic induction are different. The dependences of the minimum angle of inclination of the field lines to the radial direction from the center of the Sun and the average inclination angle of the field lines on the umbra areas of leading and trailing sunspots are also different. For magnetically coupled leading and trailing sunspots, it is shown that the distances from the center of the umbra of each type of sunspots to the main polarity separation line of the photospheric field in ARs are different. The paper also discusses the time variation of various magnetic field parameters of the sunspot umbra separately for single and magnetically coupled sunspots, as well as sunspots of magnetically coupled ARs, which we defined as magnetic activity complexes (MACs). The evolution of the magnetic characteristics of sunspots, including sunspots in the MACs, during a radical rearrangement of the magnetic configuration is studied. The influence of EPs on the characteristics of the magnetic field in sunspots is revealed. One of the objectives of this work was to reveal the difference between the properties of sunspots in ARs without EPs and in ARs with various activities, e.g., with solar flares and the formation of coronal mass ejections. Title: Long-Term Variations in Coronal Hole Areas and Occurrence of Magnetic Storms with Gradual Commencements Authors: Veretenenko, S. V.; Ogurtsov, M. G.; Obridko, V. N.; Tlatov, A. G. Bibcode: 2021Ge&Ae..61..964V Altcode: In this paper we studied long-term variations in the areas of coronal holes (CHs) reconstructed on the basis of synoptic Hα charts for the period 1887-2016 and occurrences of magnetic storms with gradual commencements. It was found that the temporal variations in mean yearly values of the CH areas in the northern and southern hemispheres are characterized by a pronounced ∼11-year periodicity, but they differ markedly on a multidecadal time scale. The wavelet spectra of the CH areas in the southern hemisphere, unlike those of the northern one, demonstrate persistent periodicities of ∼30-35 years, which are also observed in geomagnetic activity and climatic characteristics. The results of cross-wavelet analysis revealed a link between annual occurrences of magnetic storms with gradual commencements and variations in CH areas in both hemispheres. The obtained results allow us to conclude that the evolution of solar coronal holes may be considered as a possible factor of the formation of multidecadal cycles in geomagnetic activity, as well as climatic cycles. Title: Solar evolution and extrema: current state of understanding of long-term solar variability and its planetary impacts Authors: Nandy, Dibyendu; Martens, Petrus C. H.; Obridko, Vladimir; Dash, Soumyaranjan; Georgieva, Katya Bibcode: 2021PEPS....8...40N Altcode: The activity of stars such as the Sun varies over timescales ranging from the very short to the very long—stellar and planetary evolutionary timescales. Experience from our solar system indicates that short-term, transient events such as stellar flares and coronal mass ejections create hazardous space environmental conditions that impact Earth-orbiting satellites and planetary atmospheres. Extreme events such as stellar superflares may play a role in atmospheric mass loss and create conditions unsuitable for life. Slower, long-term evolutions of the activity of Sun-like stars over millennia to billions of years result in variations in stellar wind properties, radiation flux, cosmic ray flux, and frequency of magnetic storms. This coupled evolution of star-planet systems eventually determines planetary and exoplanetary habitability. The Solar Evolution and Extrema (SEE) initiative of the Variability of the Sun and Its Terrestrial Impact (VarSITI) program of the Scientific Committee on Solar-Terrestrial Physics (SCOSTEP) aimed to facilitate and build capacity in this interdisciplinary subject of broad interest in astronomy and astrophysics. In this review, we highlight progress in the major themes that were the focus of this interdisciplinary program, namely, reconstructing and understanding past solar activity including grand minima and maxima, facilitating physical dynamo-model-based predictions of future solar activity, understanding the evolution of solar activity over Earth's history including the faint young Sun paradox, and exploring solar-stellar connections with the goal of illuminating the extreme range of activity that our parent star—the Sun—may have displayed in the past, or may be capable of unleashing in the future. Title: Estimating the Energy of Solar and Stellar Superflares Authors: Katsova, M. M.; Obridko, V. N.; Sokoloff, D. D.; Livshits, I. M. Bibcode: 2021Ge&Ae..61.1063K Altcode: We discuss the current observations of the most powerful non-steady phenomena on solar-like stars. While remaining within even the most extreme solar ideas, it is very problematic to get the flare energy more than (3-5) × 1034 erg, which is apparently an absolute upper limit for solar-type flares. For explanation of the higher flare energy, about of 1036 erg, one need to adopt that spots with the magnetic field strength of a few kG should cover more than 30% of a hemisphere. This estimate leads to a mean magnetic field around 1 kG. New observational evidences for a presence of the strong magnetic fields on solar-like stars appeared recently. We discuss to what extent it is necessary to change the mechanisms of convection and dynamo with a corresponding change in the models of the atmosphere. We consider possible ways of solving the problem of the energy of superflares. Title: Zonal harmonics of solar magnetic field for solar cycle forecast Authors: Obridko, V. N.; Sokoloff, D. D.; Pipin, V. V.; Shibalva, A. S.; Livshits, I. M. Bibcode: 2021JASTP.22505743O Altcode: 2021arXiv210810527O According to the scheme of action of the solar dynamo, the poloidal magnetic field can be considered a source of production of the toroidal magnetic field by the solar differential rotation. From the polar magnetic field proxies, it is natural to expect that solar Cycle 25 will be weak as recorded in sunspot data. We suggest that there are parameters of the zonal harmonics of the solar surface magnetic field, such as the magnitude of the l = 3 harmonic or the effective multipole index, that can be used as a reasonable addition to the polar magnetic field proxies. We discuss also some specific features of solar activity indices in Cycles 23 and 24. Title: Long-term evolution of coronal holes on the Sun and occurrence frequencies of magnetic storms with gradual commencements Authors: Veretenenko, S.; Ogurtsov, M.; Obridko, V.; Tlatov, A. Bibcode: 2021JPhCS2103a2038V Altcode: Long-term evolution of areas with open configuration of magnetic field (coronal holes) on the Sun reconstructed on the basis of H-alpha synoptic charts for the period 1887-2016 was studied and compared with annual occurrence frequencies of magnetic storms with gradual (GC) commencements. It was found that correlation between yearly values of coronal hole (CH) areas and sunspot numbers with no time shift is negative and not strong, but increases up to ~0.6-0.7 when CH areas are delayed by 4-5 years relative to sunspot numbers. Temporal variations of CH areas in the Northern and Southern hemispheres are characterized by dominant ~11-year periodicities; however, they differ significantly on the multidecadal time scale. The wavelet spectra of CH areas in the Southern hemisphere, unlike those in the Northern one, reveal persistent periodicities of ~30-35 years on the studied time interval. Similar periodicities of ~30-35 years are observed in annual occurrences of GC magnetic storms which are caused by high-speed streams of solar wind from coronal holes. The results of cross wavelet analysis of annual occurrence frequencies of GC magnetic storms and areas of coronal holes revealed common periodicities ~11, ~35 and ~60 years which confirmed a close link of these storms with the evolution of large-scale magnetic fields on the Sun. Title: Medium-Term Oscillations of the Solar Activity Authors: Obridko, V. N.; Sokoloff, D. D.; Pipin, V. V.; Shibalova, A. S. Bibcode: 2021simi.conf...66O Altcode: Besides the well-known 11-year cycle, longer and shorter characteristic periods can be isolated in variations of the parameters of helio-geophysical activity. In geomagnetic variations, one can also isolate oscillations with characteristic periods of 5-6 years (QSO) and 2-3 years (QBO). Periods of ~36 and ~60 years were revealed in geomagnetic activity variations and a ~60-year periodicity, in correlation between the pressure in the lower atmosphere and the solar activity. We have considered 5-6-year periodicities observed in variations of the sunspot numbers and the intensity of the dipole component of the solar magnetic field. Comparison with different magnetic dynamo models allowed us to conjecture the origin of these oscillations. As a result of the study, we conclude that the 5-6-year activity variations are related to the processes of nonlinear saturation of the dynamo in the solar interior. Quasi-biennial oscillations are actually separate pulses related little to each other. Therefore, the methods of the spectral analysis do not reveal them over large time intervals. They are a direct product of local fields, are generated in near-surface layers, and are reliably recorded only in the epochs of high solar activity. Title: Solar large-scale magnetic field and cycle patterns in solar dynamo Authors: Obridko, V. N.; Pipin, V. V.; Sokoloff, D.; Shibalova, A. S. Bibcode: 2021MNRAS.504.4990O Altcode: 2021arXiv210406808O; 2021MNRAS.tmp.1043O We compare spectra of the zonal harmonics of the large-scale magnetic field of the Sun using observation results and solar dynamo models. The main solar activity cycle as recorded in these tracers is a much more complicated phenomenon than the eigen solution of solar dynamo equations with the growth saturated by a back reaction of the dynamo-driven magnetic field on solar hydrodynamics. The nominal 11(22)-yr cycle as recorded in each mode has a specific phase shift varying from cycle to cycle; the actual length of the cycle varies from one cycle to another and from tracer to tracer. Both the observation and the dynamo model show an exceptional role of the axisymmetric ℓ5 mode. Its origin seems to be readily connected with the formation and evolution of sunspots on the solar surface. The results of observations and dynamo models show a good agreement for the low ℓ1 and ℓ3 modes. The results for these modes do not differ significantly for the axisymmetric and non-axisymmetric models. Our findings support the idea that the sources of the solar dynamo arise as a result of both the distributed dynamo processes in the bulk of the convection zone and the surface magnetic activity. Title: Current Sheets, Plasmoids and Flux Ropes in the Heliosphere. Part II: Theoretical Aspects Authors: Pezzi, O.; Pecora, F.; Le Roux, J.; Engelbrecht, N. E.; Greco, A.; Servidio, S.; Malova, H. V.; Khabarova, O. V.; Malandraki, O.; Bruno, R.; Matthaeus, W. H.; Li, G.; Zelenyi, L. M.; Kislov, R. A.; Obridko, V. N.; Kuznetsov, V. D. Bibcode: 2021SSRv..217...39P Altcode: 2021arXiv210105007P Our understanding of processes occurring in the heliosphere historically began with reduced dimensionality - one-dimensional (1D) and two-dimensional (2D) sketches and models, which aimed to illustrate views on large-scale structures in the solar wind. However, any reduced dimensionality vision of the heliosphere limits the possible interpretations of in-situ observations. Accounting for non-planar structures, e.g. current sheets, magnetic islands, flux ropes as well as plasma bubbles, is decisive to shed the light on a variety of phenomena, such as particle acceleration and energy dissipation. In part I of this review, we have described in detail the ubiquitous and multi-scale observations of these magnetic structures in the solar wind and their significance for the acceleration of charged particles. Here, in part II, we elucidate existing theoretical paradigms of the structure of the solar wind and the interplanetary magnetic field, with particular attention to the fine structure and stability of current sheets. Differences in 2D and 3D views of processes associated with current sheets, magnetic islands and flux ropes are discussed. We finally review the results of numerical simulations and in-situ observations, pointing out the complex nature of magnetic reconnection and particle acceleration in a strongly turbulent environment. Title: Current Sheets, Plasmoids and Flux Ropes in the Heliosphere. Part I. 2-D or not 2-D? General and Observational Aspects Authors: Khabarova, O.; Malandraki, O.; Malova, H.; Kislov, R.; Greco, A.; Bruno, R.; Pezzi, O.; Servidio, S.; Li, Gang; Matthaeus, W.; Le Roux, J.; Engelbrecht, N. E.; Pecora, F.; Zelenyi, L.; Obridko, V.; Kuznetsov, V. Bibcode: 2021SSRv..217...38K Altcode: Recent accumulation of a critical mass of observational material from different spacecraft complete with the enhanced abilities of numerical methods have led to a boom of studies revealing the high complexity of processes occurring in the heliosphere. Views on the solar wind filling the interplanetary medium have dramatically developed from the beginning of the space era. A 2-D picture of the freely expanding solar corona and non-interacting solar wind structures described as planar or spherically-symmetric objects has dominated for decades. Meanwhile, the scientific community gradually moved to a modern understanding of the importance of the 3-D nature of heliospheric processes and their studies via MHD/kinetic simulations, as well as observations of large-scale flows and streams both in situ and remotely, in white light and/or via interplanetary scintillations. The new 3-D approach has provided an opportunity to understand the dynamics of heliospheric structures and processes that could not even be imagined before within the 2-D paradigm. In this review, we highlight a piece of the puzzle, showing the evolution of views on processes related to current sheets, plasmoids, blobs and flux ropes of various scales and origins in the heliosphere. The first part of the review focuses on introducing these plasma structures, discussing their key properties, and paying special attention to their observations in different space plasmas. Title: Corrigendum to "Long-term variability in occurrence frequencies of magnetic storms with sudden and gradual commencements" [J. Atmos. Sol.Terr. Phys. 205 (2020) 105295] Authors: Veretenenko, S.; Ogurtsov, M.; Obridko, V. Bibcode: 2021JASTP.21405549V Altcode: The authors regret that an error was found in the data presented in Fig.6, which displays local and global wavelet power spectra of major (strong and very strong) and moderate magnetic storms with gradual (GC) commencements. We note that the spectra of major magnetic storms (Figs.6a and b) are shown incorrectly, representing those of moderate storms after subtraction of the linear trend. The correct wavelet spectra of major GC storms are presented here in Fig.1, which replaces Fig.6 in the paper. It is seen that occurrence frequencies of these storms are characterized by persistent long-term variations, as it is stated in the paper, but their spectra do not reveal dominant periodicities of ~36, but those of ~50 years. The periodicities of ~36 years close to the Brückner climatic cycle dominate only in the spectra of moderate GC storms. The spectra of both major and moderate GC storms also show noticeable ~60-year variability. Title: Large-scale magnetic field of the Sun: Evolution of ideas Authors: Obridko, V. N. Bibcode: 2021A&AT...32..305O Altcode: In this paper, we discuss the evolution of the concept of the large-scale solar magnetic field. The priority of the large-scale field was established about 60 years ago, when it became clear that the spatial structure and evolution of the solar activity obey certain large-scale laws. The analogy between coronal holes and sunspots and the formation of global complexes of activity are discussed. A technique is presented for a quantitative analysis of the large-scale field over long time intervals based on the hypothesis of potential field in the chromosphere and corona. The concept of the global magnetic-field indices is introduced, and their relationship with other heliogeophysical indices is shown. A negative correlation has been found between the magnitude of the magnetic field and the angular rotation rate of the Sun. Title: Some Features of the Present-day Transition Period in Solar Activity Authors: Obridko, V. N.; Abunin, A. A.; Georgieva, K.; Kirov, B.; Shelting, B. D.; Livshits, I. M. Bibcode: 2020Ge&Ae..60.1007O Altcode: Various geophysical indices and their prognostic value were analyzed in (Obridko et al., 2013; Kirov et al., 2013, 2015, 2017; Georgieva et al., 2015, 2018). Two indices have been selected for the analysis (total annual Dst values, and duration of a storm). It is important to note that, unlike the other indices of solar and geophysical activity, the summary Dst index does not show violation of the Gnevyshev-Ohl rule. The analysis of annual mean Dst values reveals a clearly pronounced decrease in activity, at least since the 1980-ies. This allows us to suggest that we are at the descending branch of a secular cycle or on the threshold of a Grand Minimum. The decrease in solar activity is corroborated by the analysis of Forbush effects, solar wind speed, and intensity of the near-Earth magnetic field. Title: Magnetic Coupling of the Solar Hemispheres During the Solar Cycle Authors: Obridko, V. N.; Fainshtein, V. G.; Zagainova, Y. S.; Rudenko, G. V. Bibcode: 2020SoPh..295..149O Altcode: This work is devoted to the study of peculiarities in the magnetic coupling of the solar hemispheres over a solar activity cycle. Two approaches have been used. We have studied (i) the magnetic coupling of active regions (ARs) located in different hemispheres in the vicinity of the central meridian and, simultaneously, in the vicinity of the equator and (ii) the properties and time variation of the meridional component of the equatorial magnetic field derived from a potential-field source surface (PFSS) reconstruction at the heliocentric distance of 1.1 solar radii. In the first case, it was shown that most of the ARs in the selected pairs were magnetically connected by field lines in their leading parts. In the second case, the magnetic field monthly mean meridional component, Bθ, in the equatorial plane, which magnetically connects the two hemispheres, displayed a cyclic time variation. In the process, the extreme values of Bθ (both positive and negative) coincided in time with the sunspot maxima, and the amplitude of the Bθ extreme values decreased with decreasing height of the sunspot activity cycle. The sign of the Bθ extreme value was opposite to the sign of the forthcoming extreme value of the polar field, while the sign of Bθ coincided with that of the field lines connecting the leading spots. This means that the polar field is indeed generated by the trailing spots of ARs, and the magnetic flux of the leading spots closes through the equator. Title: Solar Quadrupole in Tensor Description Authors: Shibalova, A. S.; Obridko, V. N.; Sokolov, D. D.; Pipin, V. V. Bibcode: 2020ARep...64..855S Altcode: The cyclic variations in the quadrupole component of the solar magnetic field is studied in tensor description. The results are consistent with the classical description of the quadrupole using spherical functions, and the mathematical apparatus of tensor algebra allows one to compare the observed changes in the magnetic quadrupole and the changes predicted by the dynamo theories. In conclusion, the quadrupole properties can be adequately described by solar dynamo models that assume deviations from the dipole symmetry without the independent excitation of the quadrupole symmetry modes. Title: Young Sun, galactic processes, and origin of life Authors: Obridko, Vladimir N.; Ragulskaya, Maria V.; Khramova, Elizaveta G. Bibcode: 2020JASTP.20805395O Altcode: The paper deals with the dynamics of the young Sun, physical conditions in the early Solar System and on the Earth. An extended interpretation of the faint young Sun paradox and its possible solutions are proposed. Various hypotheses are discussed including their advantages and disadvantages. The faint young Sun paradox follows from the Standard Solar Model with the conservation of mass condition. However, the mass of the Sun did not remain constant during its evolution. It was steadily decreasing, mainly in the first 2-2.5 billion years. But even with the most optimistic estimates, the uneven loss of mass during the evolution of our star is unable to fully compensate for the lack of luminosity reaching the surface of the early Earth. The primary biosphere had to search for alternative - e.g., radiation, chemical or geothermal - sources of energy. The prevalent configurations of solar magnetic fields also changed in the course of evolution, the strong quadrupole fields dominating at the early stages. At the age of about 2-2.5 billion years and the rotation period of about 15 days, the dipole magnetic field with large mass outflow from coronal holes begins to dominate, and the steady solar wind becomes the main mechanism of mass loss in the Sun in the following two billion years. The activity of the early Sun was much higher than it is today. The high-frequency (gamma-, X-ray, and UV) radiation, radio emission, coronal mass ejections, and solar cosmic rays exceeded the present-day values by 2-3 orders of magnitude. The article emphasizes the role of the dynamics of the young Sun, cosmic rays, magnetic field and other protective shells of the Earth as factors determining the occurrence, selection, and development of the first living systems. Title: Shape of solar cycles and mid-term solar activity oscillations Authors: Sokoloff, D. D.; Shibalova, A. S.; Obridko, V. N.; Pipin, V. V. Bibcode: 2020MNRAS.497.4376S Altcode: 2020arXiv200714779S The evolution of solar activity comprises, apart from the well-known 11-year cycle, various temporal scales ranging from months up to the secondary cycles known as mid-term oscillations. Its nature deserves a physical explanation. In this work, we have considered the 5-6 year oscillations as derived both from sunspots and solar magnetic dipole time series. Using a solar dynamo model, we have deduced that these variations may be a manifestation of dynamo non-linearities and the non-harmonic shape of the solar activity cycles. We have concluded that the observed mid-term oscillations are related to the non-linear saturation of dynamo processes in the solar interior. Title: On Superflares on the Sun and Stars Authors: Katsova, M. M.; Obridko, V. N.; Sokoloff, D. D.; Livshits, I. M. Bibcode: 2020simi.conf...25K Altcode: We discuss the current observations of the most powerful non-steady phenomena on solarlike stars. While remaining within even the most extreme solar ideas, there is problematic to get the flare energy more than (3-5)x10(exp 34)erg, which is apparently an absolute upper limit for solar-type flares. For explanation of the higher flare energy, about of 10(exp 36) erg, one need to adopt that spots with the magnetic field strength of a few kG should cover more than 30 % of a hemisphere. This estimate leads to a mean magnetic field around 1kG. New observational evidences for a presence of the strong relict magnetic fields on solar-like stars appeared recently. We discuss to what extent it is necessary to change the mechanisms of convection and dynamo with a corresponding change in the models of the atmosphere. We consider possible ways of solving the problem of the energy of superflares. Title: Long-term variability in occurrence frequencies of magnetic storms with sudden and gradual commencements Authors: Veretenenko, S.; Ogurtsov, M.; Obridko, V. Bibcode: 2020JASTP.20505295V Altcode: Long-term variations in annual frequencies of occurrence of magnetic storms with sudden and gradual commencements were studied on the base of the data from IZMIRAN and Slutsk (Pavlovsk) magnetic observatories for the period 1878-2015. It was found that occurrences of strong and moderate magnetic storms with gradual commencements are characterized by a pronounced variability on the multidecadal time scale. Their wavelet spectra reveal strong periodicities of ~36 years (close to the climatic Brückner cycle), as well as less pronounced ~60-year and ~90-year ones throughout the entire time interval under study. The occurrences of strong, moderate and weak magnetic storms with sudden commencements are characterized by dominating ~11-year periodicities, whereas long-term variations are substantially weaker. The obtained results provide evidence for a different temporal evolution of local and global solar magnetic fields responsible for solar agents (CMEs and high-speed solar wind streams from coronal holes) contributing to the development of these types of magnetic storms. The obtained results allow suggesting a possible contribution of solar/geomagnetic activity to the formation of climatic oscillations on the multidecadal time scale. Title: Differential rotation of the solar corona and its importance for helioseismology Authors: Obridko, Vladimir; Badalyan, Olga Bibcode: 2020EGUGA..22.3710O Altcode: It is shown that the solar corona rotates differentially at all heliocentric distances up to the source surface. As the distance increases, the differential rotation gradient decreases, and the rotation becomes more and more rigid. At small distances, the corona at latitudes above ≈ ± 40° rotates faster than the photosphere at the same latitudes. The type of the rotation depends also on the phase of the activity cycle. The differential rotation gradient is the largest in the vicinity of the cycle minimum. It is shown that time variations in the coronal rotation characteristics are associated with the tilt of the magnetic equator of the Sun. Based on the concept that the differential rotation of the corona reflects the rotation of deep subphotospheric layers, we compared the changes in the coronal rotation characteristics with distance with the helioseismic data and showed their satisfactory agreement. The results obtained allow us to suggest that the rotation of the solar corona can be used as indicator of the differential rotation of subphotospheric layers and calculate the nature of some current sheets in heliosphere/ Title: Solar Activity Indices for Ionospheric Parameters in the 23rd and 24th Cycles Authors: Deminov, M. G.; Nepomnyashchaya, E. V.; Obridko, V. N. Bibcode: 2020Ge&Ae..60....1D Altcode: Characteristics of changes in the solar activity indices (the flux of the solar radio emission at a wavelength of 10.7 cm F and the new version of the relative sunspot number Ri) and the ionospheric index of this activity T in the 23rd and 24th solar cycles, which were low by the amplitude of solar and geomagnetic activity, are analyzed. The running mean over 12 months and smoothed (by a 24-month filter) values of these indices are considered in the analysis. It is found that the relation between the T and F indices was on average stable for these cycles and did not differ from the previous solar cycles. The relation between the T and Ri indices changed with time in the 23rd and 24th cycles and was different from the previous cycles. Moreover, a distinct hysteresis effect in the dependence of the smoothed values of T on Ri was observed in the 24th cycle when different values of T corresponded to a fixed value of Ri in the growing and declining phases of the solar cycle. This effect was absent in the dependence of T on F. Thus, it is confirmed that the F index is a more exact indicator of solar activity for the ionosphere than Ri.</sec> Title: Cycle-dependent and cycle-independent surface tracers of solar magnetic activity Authors: Sokoloff, D. D.; Obridko, V. N.; Livshits, I. M.; Shibalova, A. S. Bibcode: 2020IAUGA..30..342S Altcode: We consider several tracers of magnetic activity that separate cycle-dependent contributions to the background solar magnetic field from those that are independent of the cycle. The main message is that background fields include two relative separate populations. The background fields with a strength up to 100 Mx cm-2 are very poorly correlated with the sunspot numbers and vary little with the phase of the cycle. In contrast, stronger magnetic fields demonstrate pronounced cyclic behaviour. Small-scale solar magnetic fields demonstrate features of fractal intermittent behaviour, which requires quantification. We investigate how the observational estimate of the solar magnetic flux density B depends on resolution D in order to obtain the scaling In BD = -k In D + a in a reasonably wide range. The quantity k demonstrates cyclic variations typical of a solar activity cycle. k depends on the magnetic flux density, i.e. the ratio of the magnetic flux to the area over which the flux is calculated, at a given instant. The quantity a demonstrates some cyclic variation, but it is much weaker than in the case of k. The scaling is typical of fractal structures. The results obtained trace small-scale action in the solar convective zone and its coexistence with the conventional large-scale solar dynamo based on differential rotation and mirror-asymmetric convection. Here we discuss the message for solar dynamo studies hidden in the above results. Title: Cyclic variations in the main components of the solar large-scale magnetic field Authors: Obridko, V. N.; Sokoloff, D. D.; Shelting, B. D.; Shibalova, A. S.; Livshits, I. M. Bibcode: 2020MNRAS.492.5582O Altcode: 2020arXiv200105433O We consider variations of the dipole and quadrupole components of the solar large-scale magnetic field. Both axial and equatorial dipoles exhibit a systematic decrease during the past four cycles, in accordance with the general decrease of solar activity. The transition of the pole of a dipole from the polar region to the midlatitudes occurs rather quickly, so that the longitude of the pole changes little. With time, however, this inclined dipole region shifts to larger longitudes, which suggests an acceleration of dipole rotation. The mean rotation rate exceeds the Carrington velocity by 0.6 per cent. The behaviour of a quadrupole differs dramatically. Its decrease over the last four cycles was much smaller than that of the dipole moment. The ratio of the quadrupole and dipole moments has increased for four cycles more than twice, in contrast to sunspot numbers, which displayed a twofold decrease for the same time interval. Regarding quadrupole rotation, the mean longitude of the poles of one sign decreased by 600° over four cycles, which suggests that the mean rotation rate was lower than the Carrington velocity by 0.28 per cent. We do not, however, see any conclusive evidence that, in the period under discussion, a mode of quadrupole symmetry was excited in the Sun along with the dipole mode. Title: Physical conditions in the early Solar system and life origin: compatible models Authors: Ragulskaya, Mariya; Khramova, Elizaveta; Obridko, Vladimir Bibcode: 2020IAUS..345..347R Altcode: The article discusses the physical conditions in the early Solar system and on Earth, determining the origin, selection and development of the first living systems. The role of the young Sun dynamics, cosmic rays, magnetic fields and other protective shells of the Earth in the formation of the biosphere is emphasized. The selection of a single genetic code, ancient methods of long-term storage of energy and adaptive technologies of the first living systems occurred under the influence of cosmological and geophysical factors. A hypothesis was suggested that the accumulation of energy in polyphosphates without the participation of solar radiation could have ensured the survival of the primary biosphere in the conditions of the low luminosity of the young Sun. Title: Solar Corona as Indicator of Differential Rotation of Subphotospheric Layers Authors: Obridko, V. N.; Badalyan, O. G. Bibcode: 2020CosRe..57..407O Altcode: In our earlier work [2-4], we proposed using the coronal magnetic field as an implicit tracer when studying the properties of differential rotation of the solar corona. At present, this is virtually the only way to study the rotation of the Sun at large heliocentric distances up to the source surface. In the present work, calculations of the coronal magnetic field have been extended over a longer time interval, till December 31, 2015. It is shown that the solar corona rotates differentially at all heliocentric distances up to the source surface. The differential rotation gradient decreases with distance. As we approach the source surface, the corona rotation becomes more rigid, but even at large heliocentric distances it remains slightly differential. We believe that the differential rotation of the solar corona reflects the rotation of deep subphotospheric layers. In this case, the behavior of the coronal rotation characteristics can be used as indicator of differential rotation of the subphotospheric layers. We have compared the changes in the coronal rotation characteristics with distance with helioseismic data and obtained a satisfactory agreement. Cycle variations in the differential rotation of subphotospheric layers have been investigated for the first time. Title: Analysis of the Hemispheric Sunspot Number Time Series for the Solar Cycles 18 to 24 Authors: Chowdhury, P.; Kilcik, A.; Yurchyshyn, V.; Obridko, V. N.; Rozelot, J. P. Bibcode: 2019SoPh..294..142C Altcode: In this article, we investigate temporal and periodic variations of the hemispheric sunspot number using sunspot data from Kanzelhöhe Solar Observatory (KSO) for the time period of 1944 - 2017, which covers Solar Cycles 18 to 23 and almost the entire Solar Cycle 24 (2009 - 2017). The KSO data set was verified against the International Sunspot Number (ISSN) data. Temporal and periodic variations in the KSO data were analyzed using cross-correlation analysis, Morlet wavelet and multitaper (MTM) period analysis methods. We find that: i) sunspot numbers, as derived from both KSO and ISSN time series, are highly correlated with one another; ii) the temporal evolution of the sunspot number differs from one hemisphere to another with the solar cycle peaking at different times in each hemisphere; iii) the northern hemisphere showed two- and seven-month lead in Solar Cycles 18 and 19, respectively, while the southern hemisphere was leading in the rest of the cycles with the varying lead time ranging from 2 to 14 months; iv) apart from the fundamental mode of ≈ 11 years, Solar Cycle, the KSO data also show several midterm variations in the opposite hemispheres, specifically, Rieger-type and quasi-biennial periodicities - the detected midterm periodicities also differ in the northern and southern hemispheres; v) our results confirm the Waldmeier effect, which correlates the rise time with the cycle amplitude using the new sunspot data set from KSO. Title: The Young Sun, Conditions on the Early Earth, and the Origin of Life Authors: Ragulskaya, M. V.; Khramova, E. G.; Obridko, V. N. Bibcode: 2018Ge&Ae..58..877R Altcode: The article analyzes the existing theoretical models of the formation of the solar system and the early physical conditions on Earth from the point of view of the possibility for the development of life in its present form. We show that the origin of the biosphere and geomagnetic field was determined not only by the conditions on the Earth itself but also by the dynamics of the early Sun, the migration of giant planets, and the formation of the Earth-Moon system. Also considered are the possibilities for the search for bacterial life beyond the Earth: on Mars, on satellites of Giant planets, on the outer asteroid belt, and on exoplanets. Title: Differential Rotation of the Solar Corona from Magnetic Field Data Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 2018AstL...44..727B Altcode: A method for investigating the differential rotation of the solar corona using the coronal magnetic field as a tracer is proposed. The magnetic field is calculated in the potential approximation from observational data at the photospheric level. The time interval from June 24, 1976, to December 31, 2004, is considered. The magnetic field has been calculated for all latitudes from the equator to ±75° with a 5° step at distances from the base of the corona 1.0 R to 2.45 R near the source surface. The coronal rotation periods at 14 distances from the solar center have been determined by the method of periodogram analysis. The coronal rotation is shown to become progressively less differential with increasing heliocentric distance; it does not become rigid even near the source surface. The change in the coronal rotation periods with time is considered. At the cycleminimumthe rotation has been found to bemost differential, especially at small distances from the solar center. The change in coronal rotation with time is consistent with the tilt of the solar magnetic equator. The results from the magnetic field are compared with those obtained from the brightness of the green coronal Fe XIV 530.3 nm line. The consistency between these results confirms the reliability of the proposed method for studying the coronal rotation. Studying the rotation of the coronal magnetic field gives hope for the possibility of using this method to diagnose the differential rotation in subphotospheric layers. Title: Magnetic Field as a Tracer for Studying the Differential Rotation of the Solar Corona Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 2018SoPh..293..128B Altcode: 2018arXiv180805515B The characteristics of differential rotation of the solar corona for the period 1976 - 2004 were studied as a function of the distance from the center of the Sun. For this study, we developed a method using the coronal magnetic field as a tracer. The field in a spherical layer from the base of the corona up to the source surface was determined from photospheric measurements. Calculations were performed for 14 heliocentric distances from the base of the corona up to 2.45 R solar radii (the vicinity of the source surface) and from the equator to ±75 of latitude at 5 steps. For each day, we calculated three spherical components, which were then used to obtain the field strength. The coronal rotation periods were determined by the periodogram method. The rotation periods were calculated for all distances and latitudes under consideration. The results of these calculations make it possible to study the distribution of the rotation periods in the corona depending on distance, time, and phase of the cycle. The variations in the coronal differential rotation during the time interval 1976 - 2004 were as follows: the gradient of differential rotation decreased with the increase of heliocentric distance; the rotation remaining differential even in the vicinity of the source surface. The highest rotation rates (shortest rotation periods) were recorded at the cycle minimum at small heliospheric distances, i.e. small heights in the corona. The lowest rotation rate was observed at the middle of the ascending branch at large distances. At the minimum of the cycle, the differential rotation is most clearly pronounced, especially at small heliocentric distances. As the distance increases, the differential rotation gradient decreases in all phases. The results based on magnetic data and on the brightness of the coronal green line 530.3 nm Fe XIV used earlier show a satisfactory agreement. Since the rotation of the magnetic field at the corresponding heights in the corona is probably determined by the conditions in the field generation region, an opportunity arises to use this method for diagnostics of differential rotation in the subphotospheric layers. Title: Solar activity in the following decades Authors: Obridko, V.; Georgieva, K. Bibcode: 2018JASTP.176....1O Altcode: Welcome to the JASTP Special Issue on Expected Evolution of Solar Activity in the Following Decades. Title: Properties of the Ionosphere at the Fall and Minimum Phases of the Latest Solar Cycles Authors: Deminov, M. G.; Nepomnyashchaya, E. V.; Obridko, V. N. Bibcode: 2018stpc.conf...72D Altcode: The properties of the ionosphere in solar cycles 23 and 24 were studied on the basis of the comparison of the solar activity indices (F10.7 and Ri) with the ionospheric index of this activity T. It was found that in cycle 24 the hysteresis effect was observed in the dependence of T on Ri. This effect was absent in the dependence of T on F10.7. Title: Forecasting the sunspot maximum through an analysis of geomagnetic activity Authors: Kirov, B.; Asenovski, S.; Georgieva, K.; Obridko, V. N.; Maris-Muntean, G. Bibcode: 2018JASTP.176...42K Altcode: In the present work we show that it is possible to predict the maximum sunspot number for a particular solar cycle from the maximum value of the solar dipole magnetic field of the previous cycle. Based on the measured dipole field maximum, we determine the geomagnetic activity in the upcoming solar minimum during the intervals when the Earth is not exposed to CME and HSS influences. The physical meaning of the relationship between the geomagnetic activity in the solar activity minimum and the maximum value of the solar dipole magnetic field is that the basic factor determining the geomagnetic activity during the minimum is not the heliospheric current sheet thickness but the physical parameters of the slow solar wind in this period.

Then, based on the established relationship between the average geomagnetic activity at the specified minimum and the next solar maximum, we can predict the sunspot maximum of the next solar cycle. Title: Do the sunspot umbra magnetic field characteristics vary during flares and coronal mass ejections? Authors: Zagainova, Iuliia; Obridko, Vladimir; Rudenko, George; Fainshtein, Victor Bibcode: 2018cosp...42E3795Z Altcode: We found variations in the sunspot umbra magnetic field characteristics within active regions (ARs), where eruptive events (solar flares, coronal mass ejections (CMEs)) originated. The behavior of the maximum of the module of magnetic induction B_{max}, the minimum inclination of the magnetic field lines to the normal α_{min} and their averages values (B_{mean} and α_{mean}) within umbrae were analyzed. A change of behavior of the magnetic field parameters after flare beginning is observed. Thus, for example, during 3 hours before a solar flare/eruption the _min angle in umbrae of the sunspots closely located to the "feet" of an eruptive rope is increasing to a larger values (4° through 10°). Later a strong decreasing over 1 _ 3 hours after the flare onset to small values (≤1°) is observed. At the same time the α_{mean} angle varies essentially more weakly. This implies that the magnetic tube from the umbra of such sunspots after the flare onset deflects from the initial position almost as a whole, i.e. without essential transformation in the distribution of the magnetic field lines inside the tube. Title: Sources and transport of energetic particles at high heliolatitudes Authors: Khabarova, Olga; Bemporad, Alessandro; Obridko, Vladimir; Malandraki, Olga; Malova, Helmi; Kislov, Roman; Kuznetsov, Vladimir; Cremades, Hebe; Kharshiladze, Alexander; Merenda, Luciano A. Bibcode: 2018cosp...42E1739K Altcode: Understanding the origin and transport of energetic particles of keV-MeV energies throughout the heliosphere still represents one of the biggest problems of space physics. Our knowledge of the propagation of energetic particles is mostly based on theoretical predictions compared with spacecraft observations at low heliolatitudes. Meanwhile, the occurrence of energetic particles at high heliolatitudes is even more puzzling since only one spacecraft, Ulysses, flew over the poles of the Sun and provided information on the energetic particle properties far above the ecliptic plane. Ulysses observations show that energetic particle flux enhancements occur at heliolatitudes over 40 degrees at both solar maximum and minimum conditions (see, e.g., Smith et al. 2001; Sanderson et al. 2003; Lario et al. 2004; Sanderson 2004; Malandraki et al. 2009). This suggests various scenarios of particle transport. Energetic particles of keV-MeV energies should propagate mainly along magnetic field lines, but if a source is an active region at low latitudes or an ICME, their detection at high latitudes can be explained by particle diffusion across magnetic field lines either in the solar wind or in the corona. In any event, sources of energetic particles observed above the ecliptic during solar maxima are more or less well identified.Interpretations of observations of keV-MeV energetic particles in polar regions during solar minima are more complicated. The association of energetic particle flux enhancements in the polar heliosphere with corotating interaction regions, the main sources of accelerated particles in quiet times, is sometimes unsuccessful since there are no signatures of cross-field diffusion or particle streaming from distant heliocentric distances back to the Sun as it was presumed. The existence of long-lived conic (or cylindrical) current sheets (CCSs) in the polar solar wind can naturally solve this problem (Khabarova et al. 2017). It has been recently found that CCSs are low-beta and low-speed structures formed within polar coronal holes. CCS stability is supported by the tornado-like magnetic field. The occurrence of magnetic separators near the poles in solar minima is confirmed independently by reconstructions of the coronal magnetic field based on photospheric magnetic field charts. We show evidence for association of energetic particles observed by Ulysses above the pole with reconnection polar jets located at the circle-shaped touchdown of a CCS. Therefore, it is demonstrated that CCSs might serve as channels for energetic particles accelerated in the solar corona by magnetic reconnection, which sheds light on the mystery of energetic particles observed at high heliolatitudes. This work is partly supported by the International Space Science Institute (ISSI) in the framework of International Team 405 entitled "Current Sheets, Turbulence, Structures and Particle Acceleration in the Heliosphere." and RFBR grants 16-02-00479, 17-02-00300 and 17-02-01328. Khabarova O.V. et al., High-latitude conic current sheets in the solar wind, The Astrophysical Journal, 836, 108, 1, 2017, https://doi.org/10.3847/1538-4357/836/1/108 Title: Parameters of the Geomagnetic Activity, Thermosphere, and Ionosphere for the Ultimately Intense Magnetic Storm Authors: Deminov, M. G.; Belov, A. V.; Nepomnyashchaya, E. V.; Obridko, V. N. Bibcode: 2018Ge&Ae..58..501D Altcode: Equations of regression are derived for the intense magnetic storms of 1957-2016. They reflect the nonlinear relation between Dst min and the effective index of geomagnetic activity Ap(τ) with a timeweighted factor τ. Based on this and on known estimations of the upper limit of the magnetic storm intensity ( Dst min =-2500 nT), the maximal possible value Ap(τ)max 1000 nT is obtained. This makes it possible to obtain initial estimates of the upper limit of variations in some parameters of the thermosphere and ionosphere that are due to geomagnetic activity. It is found, in particular, that the upper limit of an increase in the thermospheric density is seven to eight times larger than for the storm in March 1989, which was the most intense for the entire space era. The maximum possible amplitude of the negative phase of the ionospheric storm in the number density of the F 2-layer maximum at midlatitudes is nearly six times higher than for the March 1989 storm. The upper limit of the F 2-layer rise in this phase of the ionospheric storm is also considerable. Based on qualitative analysis, it is found that the F 2-layer maximum in daytime hours at midlatitudes for these limiting conditions is not pronounced and even may be unresolved in the experiment, i.e., above the F 1-layer maximum, the electron number density may smoothly decrease with height up to the upper boundary of the plasmasphere. Title: The evolution of flaring and non-flaring active regions Authors: Kilcik, A.; Yurchyshyn, V.; Sahin, S.; Sarp, V.; Obridko, V.; Ozguc, A.; Rozelot, J. P. Bibcode: 2018MNRAS.477..293K Altcode: According to the modified Zurich classification, sunspot groups are classified into seven different classes (A, B, C, D, E, F and H) based on their morphology and evolution. In this classification, classes A and B, which are small groups, describe the beginning of sunspot evolution, while classes D, E and F describe the large and evolved groups. Class C describes the middle phase of sunspot evolution and the class H describes the end of sunspot evolution. Here, we compare the lifetime and temporal evolution of flaring and non-flaring active regions (ARs), and the flaring effect on ARs in these groups in detail for the last two solar cycles (1996 through 2016). Our main findings are as follows: (i) Flaring sunspot groups have longer lifetimes than non-flaring ones. (ii) Most of the class A, B and C flaring ARs rapidly evolve to higher classes, while this is not applicable for non-flaring ARs. More than 50 per cent of the flaring A, B and C groups changed morphologically, while the remaining D, E, F and H groups did not change remarkably after the flare activity. (iii) 75 per cent of all flaring sunspot groups are large and complex. (iv) There is a significant increase in the sunspot group area in classes A, B, C, D and H after flaring activity. In contrast, the sunspot group area of classes E and F decreased. The sunspot counts of classes D, E and F decreased as well, while classes A, B, C and H showed an increase. Title: Temporal and Periodic Variations of Sunspot Counts in Flaring and Non-Flaring Active Regions Authors: Kilcik, A.; Yurchyshyn, V.; Donmez, B.; Obridko, V. N.; Ozguc, A.; Rozelot, J. P. Bibcode: 2018SoPh..293...63K Altcode: 2017arXiv170509065K We analyzed temporal and periodic variations of sunspot counts (SSCs) in flaring (C-, M-, or X-class flares), and non-flaring active regions (ARs) for nearly three solar cycles (1986 through 2016). Our main findings are as follows: i) temporal variations of monthly means of the daily total SSCs in flaring and non-flaring ARs behave differently during a solar cycle and the behavior varies from one cycle to another; during Solar Cycle 23 temporal SSC profiles of non-flaring ARs are wider than those of flaring ARs, while they are almost the same during Solar Cycle 22 and the current Cycle 24. The SSC profiles show a multi-peak structure and the second peak of flaring ARs dominates the current Cycle 24, while the difference between peaks is less pronounced during Solar Cycles 22 and 23. The first and second SSC peaks of non-flaring ARs have comparable magnitude in the current solar cycle, while the first peak is nearly absent in the case of the flaring ARs of the same cycle. ii) Periodic variations observed in the SSCs profiles of flaring and non-flaring ARs derived from the multi-taper method (MTM) spectrum and wavelet scalograms are quite different as well, and they vary from one solar cycle to another. The largest detected period in flaring ARs is 113 ±1.6 days while we detected much longer periodicities (327 ±13 , 312 ±11 , and 256 ±8 days) in the non-flaring AR profiles. No meaningful periodicities were detected in the MTM spectrum of flaring ARs exceeding 55 ±0.7 days during Solar Cycles 22 and 24, while a 113 ±1.3 days period was detected in flaring ARs of Solar Cycle 23. For the non-flaring ARs the largest detected period was only 31 ±0.2 days for Cycle 22 and 72 ±1.3 days for the current Cycle 24, while the largest measured period was 327 ±13 days during Solar Cycle 23. Title: Some Statistical Properties of Magnetic Fields and Sunspots Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2018RNAAS...2...40O Altcode: 2018RNAAS...2a..40O No abstract at ADS Title: Some Features of the Variation of the Magnetic Field Characteristics in the Umbra of Sunspots During Flares and Coronal Mass Ejections Authors: Zagainova, Yu. S.; Fainshtein, V. G.; Rudenko, G. V.; Obridko, V. N. Bibcode: 2017Ge&Ae..57..835Z Altcode: The observed variations of the magnetic properties of sunspots during eruptive events (solar flares and coronal mass ejections (CMEs)) are discussed. Variations of the magnetic field characteristics in the umbra of the sunspots of active regions (ARs) recorded during eruptive events on August 2, 2011, March 9, 2012, April 11, 2013, January 7, 2014, and June 18, 2015, are studied. The behavior of the maximum of the total field strength B max, the minimum inclination angle of the field lines to the radial direction from the center of the Sun αmin (i.e., the inclination angle of the axis of the magnetic tube from the sunspot umbra), and values of these parameters B mean and αmean mean within the umbra are analyzed. The main results of our investigation are discussed by the example of the event on August 2, 2011, but, in general, the observed features of the variation of magnetic field properties in AR sunspots are similar for all of the considered eruptive events. It is shown that, after the flare onset in six AR sunspots on August 2, 2011, the behavior of the specified magnetic field parameters changes in comparison with that observed before the flare onset. Title: Two populations of the solar magnetic field Authors: Obridko, V. N.; Livshits, I. M.; Sokoloff, D. D. Bibcode: 2017MNRAS.472.2575O Altcode: Dynamo theory suggests that there are two types of solar dynamo, namely the conventional mean-field dynamo, which produces large- and small-scale magnetic fields involved in the activity cycle, and also the small-scale dynamo, which produces a cycle independent small-scale magnetic field. The relative contribution of the two mechanisms to solar magnetism remains a matter of scientific debate, which includes the opinion that the contribution of the small-scale dynamo is negligible. Here, we consider several tracers of magnetic activity that separate cycle-dependent contributions to the background solar magnetic field from those that are independent of the cycle. We call background fields the magnetic fields outside active regions and give further development of this concept. The main message of our paper is that background fields include two relative separate populations. The background fields with a strength up to 100 Mx cm-2 are very poorly correlated with the sunspot numbers and vary little with the phase of the cycle. In contrast, stronger magnetic fields demonstrate pronounced cyclic behaviour. We discuss how this result can be included in the above-mentioned concepts of solar dynamo studies. Title: The Sun and the Biosphere: the Paradoxes of 4 Billion Years of Coexistence Authors: Ragulskaya, M. V.; Obridko, V. N. Bibcode: 2017RRPRA..22..276R Altcode: No abstract at ADS Title: Comparison of Magnetic Properties and Shadow Area of Leading and Trailing Spots with Different Asymmetries Authors: Zagainova, Yu. S.; Fainshtein, V. G.; Obridko, V. N.; Rudenko, V. G. Bibcode: 2017Ge&Ae..57..946Z Altcode: The magnetic properties of the shadow of magnetic-related leading and trailing spots (those connected by forces lines of magnetic field, which are calculated from a field in potential approximation) are studied in this work. The correlations are established between individual characteristics of the field in the spot shadow and these characteristics from the shadow area S for spot pairs, for which the minimum angle between the measured vector of magnetic induction B in the shadow of the leading (L) spot and positive normal to the solar surface is lower than in the trailing (F) spot (αmin-L < αmin-F) and, vice versa, when αmin-L > αmin-F. It is shown that the αmin-L( S L), αmin-F( S F), Bmax-L( S L) and Bmax-F( S F) correlations are similar behaviorally and quantitatively for two groups of spots with different asymmetries of a magnetically connected field ( B max-L, F is the maximum of magnetic induction in the shadow of leading and trailing spots). The correlation between the average angles within the spot shadow <αL, F> and the area of the spot shadow S L, F and between the average value of magnetic induction in the spot shadow < B L, F> differ in two cases. In most studied spot pairs, the leading spot is closer to the dividing line of polarity between the spots rather than the trailing one. Title: On the nature of the magnetic field asymmetry in magnetically coupled leading and following sunspots observed in active regions with no eruptive events Authors: Zagainova, Iu. S.; Fainshtein, V. G.; Rudenko, G. V.; Obridko, V. N. Bibcode: 2017arXiv171108895Z Altcode: In this study, we investigate magnetic properties of umbra of magneto-conjugate leading and following sunspots, i.e. connected through magnetic field lines. We established dependences between individual sunspot umbra field characteristics, and between these characteristics on the umbra area ($S$) separately for sunspot pairs, for which the minimal angle between the umbra magnetic field line of the leading ($L$) sunspot and the positive normal line to the Sun surface is smaller, than that in the following ($F$) sunspot ($\alpha_{min-L}<\alpha_{min-F}$; such sunspot pairs are the bulk) and, on the contrary, when $\alpha_{min-L}>\alpha_{min-F}$. The $\alpha_{min-L}(S_L)$, $\alpha_{min-F}(S_F)$, $B_{max-L}(S_L)$ and $B_{max-F}(S_F)$ dependences are shown to have similar behavior features, and are quantitatively close for two sunspot groups with a different asymmetry of the sunspot magnetic field connecting them (here, $B_{max-L,F}(S_L)$ is the magnetic induction maximum induction in umbrae of the leading and the following sunspots). The dependence of mean values of angles within umbra $<\alpha_{L,F}>$ on the sunspot umbra area $S_{L,F}$ and on the mean value of magnetic induction in umbra $<B_{L,F}>$ appeared different for two cases. Also, in the bulk of the investigated sunspot pairs, the leading sunspot was shown to appear closer to the polarity inversion line between the sunspots, than the following one. This result and the conclusion that, in the bulk of the investigated pairs of the magnetically conjugate sunspots, $\alpha_{min-L}<\alpha_{min-F}$ are closely coupled. Title: Meridional component of the large-scale magnetic field at minimum and characteristics of the subsequent solar activity cycle Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2017AstL...43..697O Altcode: The polar magnetic field near the cycle minimum is known to correlate with the height of the next sunspot maximum. There is reason to believe that the hemispheric coupling can play an important role in forming the next cycle. The meridional component of the large-scale magnetic field can be one of the hemispheric coupling indices. For our analysis we have used the reconstructed data on the large-scale magnetic field over 1915-1986. We show that in several cycles not only the height but also the general course of the cycle can be described in this way about 6 years in advance. This coupling has been confirmed by the currently available data from 1976 to 2016, but the ratio of the meridional field to the total absolute value of the field vector has turned out to be a more promising parameter. In this paper it was calculated at a height of ∼70 Mm above the photosphere. The date of the forthcoming minimum is estimated using this parameter to be mid-2018; using the global field as a forecast parameter gives a later date of the minimum, early 2020. Title: North-south asymmetry of solar activity as a superposition of two realizations - the sign and absolute value Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 2017A&A...603A.109B Altcode: Context. Since the occurrence of north-south asymmetry (NSA) of alternating sign may be determined by different mechanisms, the frequency and amplitude characteristics of this phenomenon should be considered separately.
Aims: We propose a new approach to the description of the NSA of solar activity.
Methods: The asymmetry defined as A = (N-S)/(N + S) (where N and S are, respectively, the indices of activity of the northern and southern hemispheres) is treated as a superposition of two functions: the sign of asymmetry (signature) and its absolute value (modulus). This approach is applied to the analysis of the NSA of sunspot group areas for the period 1874-2013.
Results: We show that the sign of asymmetry provides information on the behavior of the asymmetry. In particular, it displays quasi-periodic variation with a period of 12 yr and quasi-biennial oscillations as the asymmetry itself. The statistics of the so-called monochrome intervals (long periods of positive or negative asymmetry) are considered and it is shown that the distribution of these intervals is described by the random distribution law. This means that the dynamo mechanisms governing the cyclic variation of solar activity must involve random processes. At the same time, the asymmetry modulus has completely different statistical properties and is probably associated with processes that determine the amplitude of the cycle. One can reliably isolate an 11-yr cycle in the behavior of the asymmetry absolute value shifted by half a period with respect to the Wolf numbers. It is shown that the asymmetry modulus has a significant prognostic value: the higher the maximum of the asymmetry modulus, the lower the following Wolf number maximum.
Conclusions: A fundamental nature of this concept of NSA is discussed in the context of the general methodology of cognizing the world. It is supposed that the proposed description of the NSA will help clarify the nature of this phenomenon. Title: Comparison of the magnetic properties of leading and following spots and the overlying ultraviolet emission Authors: Zagainova, Yu. S.; Fainshtein, V. G.; Obridko, V. N.; Rudenko, G. V. Bibcode: 2017ARep...61..533Z Altcode: SDO/HMI and SDO/AIA data for the 24th solar-activity cycle are analyzed using a quicker and more accurate method for resolving π ambiguities in the transverse component of the photospheric magnetic field, yielding new results and confirming some earlier results on the magnetic properties of leading and following magnetically connected spots and single spots. The minimum inclination of the field lines to the positive normal to the solar surface α min within umbrae is smaller in leading than in following spots in 78% of the spot pairs considered; the same trend is found for the mean angle < α> in 83% of the spot pairs. Positive correlations between the α min values and the < α> values in leading and following spots are also found. On average, in umbrae, the mean values of < B>, the umbra area S, and the angles α min and < α> decrease with growth in the maximum magnetic field B max in both leading and following spots. The presence of a positive correlation between B max and S is confirmed, and a positive correlation between < B> and S in leading and following spots has been found. Themagnetic properties of the umbrae of magnetically connected pairs of spots are compared with the contrast of the He II 304 emission above the umbrae, C 304. Spots satisfying certain conditions display a positive correlation between C 304- L and < α L > for the leading (L) spots, and between C 304- L / C 304- F and l L / l F , where l L ( l F ) are the lengths of the field lines connecting leading (L) or following (F) spots from the corresponding spot umbrae to the apex of the field line. Title: 22-year cycle of differential rotation of the solar corona and the rule by Gnevyshev-Ohl Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 2017MNRAS.466.4535B Altcode: 2017MNRAS.tmp..137B The time variation of the parameters of differential rotation of the solar corona is considered based on data on the coronal green-line brightness. Separate analysis is performed for even and odd cycles. It is shown that the equatorial rotation rate of the corona increases in the epochs of minimum between the even and odd cycles and reaches its minimum values between the odd and even cycles. Besides, it is found that the differential rotation gradient in absolute value increases in the even cycles. Both these factors may act to increase the amplitude of the odd cycle compared to the preceding even one. Perhaps, this is what explains the effect of Gnevyshev-Ohl. Title: Polar conic current sheets as sources and channels of energetic particles in the high-latitude heliosphere Authors: Khabarova, Olga; Malova, Helmi; Kislov, Roman; Zelenyi, Lev; Obridko, Vladimir; Kharshiladze, Alexander; Tokumaru, Munetoshi; Sokół, Justyna; Grzedzielski, Stan; Fujiki, Ken'ichi; Malandraki, Olga Bibcode: 2017EGUGA..1918130K Altcode: The existence of a large-scale magnetically separated conic region inside the polar coronal hole has been predicted by the Fisk-Parker hybrid heliospheric magnetic field model in the modification of Burger and co-workers (Burger et al., ApJ, 2008). Recently, long-lived conic (or cylindrical) current sheets (CCSs) have been found from Ulysses observations at high heliolatitudes (Khabarova et al., ApJ, 2017). The characteristic scale of these structures is several times lesser than the typical width of coronal holes, and the CCSs can be observed at 2-3 AU for several months. CCS crossings in 1994 and 2007 are characterized by sharp decreases in the solar wind speed and plasma beta typical for predicted profiles of CCSs. In 2007, a CCS was detected directly over the South Pole and strongly highlighted by the interaction with comet McNaught. The finding is confirmed by restorations of solar coronal magnetic field lines that reveal the occurrence of conic-like magnetic separators over the solar poles both in 1994 and 2007. Interplanetary scintillation data analysis also confirms the existence of long-lived low-speed regions surrounded by the typical polar high-speed solar wind in solar minima. The occurrence of long-lived CCSs in the high-latitude solar wind could shed light on how energetic particles reach high latitudes. Energetic particle enhancements up to tens MeV were observed by Ulysses at edges of CCSs both in 1994 and 2007. In 1994 this effect was clearer, probably due to technical reasons. Accelerated particles could be produced either by magnetic reconnection at the edges of a CCS in the solar corona or in the solar wind. We discuss the role of high-latitude CCSs in propagation of energetic particles in the heliosphere and revisit previous studies of energetic particle enhancements at high heliolatitudes. We also suggest that the existence of a CCS can modify the distribution of the solar wind as a function of heliolatitude and consequently impact ionization rates of heliospheric particles such as neutral interstellar gas atoms, pick-up ions or energetic neutral atoms This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324 and the Russian Foundation for Basic Research under grant agreements No 17-02-00300 & No 17-02-01328. O. Khabarova, H. Malova, R. Kislov, L. Zelenyi, V. Obridko, A. Kharshiladze, M. Tokumaru , J. Sokół, S. Grzedzielski, K. Fujiki, 2017, the Astrophysical Journal, under review Title: On the history of the solar wind discovery Authors: Obridko, V. N.; Vaisberg, O. L. Bibcode: 2017SoSyR..51..165O Altcode: The discovery of the solar wind has been an outstanding achievement in heliophysics and space physics. The solar wind plays a crucial role in the processes taking place in the Solar System. In recent decades, it has been recognized as the main factor that controls the terrestrial effects of space weather. The solar wind is an unusual plasma laboratory of giant scale with a fantastic diversity of parameters and operating modes, and devoid of influence from the walls of laboratory plasma systems. It is also the only kind of stellar wind accessible for direct study. The history of this discovery is quite dramatic. Like many remarkable discoveries, it had several predecessors. However, the honor of a discovery usually belongs to a scientist who was able to more fully explain the phenomenon. Such a man is deservedly considered the US theorist Eugene Parker, who discovered the solar wind, as we know it today, almost "with the point of his pen". In 2017, we will celebrate the 90th anniversary birthday of Eugene Parker. Title: Intermittency of the Solar Magnetic Field and Solar Magnetic Activity Cycle Authors: Shibalova, A. S.; Obridko, V. N.; Sokoloff, D. D. Bibcode: 2017SoPh..292...44S Altcode: Small-scale solar magnetic fields demonstrate features of fractal intermittent behavior, which requires quantification. For this purpose we investigate how the observational estimate of the solar magnetic flux density B depends on resolution D in order to obtain the scaling lnBD=−k lnD +a in a reasonably wide range. The quantity k demonstrates cyclic variations typical of a solar activity cycle. In addition, k depends on the magnetic flux density, i.e. the ratio of the magnetic flux to the area over which the flux is calculated, at a given instant. The quantity a demonstrates some cyclic variation, but it is much weaker than in the case of k . The scaling obtained generalizes previous scalings found for the particular cycle phases. The scaling is typical of fractal structures. In our opinion, the results obtained trace small-scale action in the solar convective zone and its coexistence with the conventional large-scale solar dynamo based on differential rotation and mirror-asymmetric convection. Title: High-latitude Conic Current Sheets in the Solar Wind Authors: Khabarova, Olga V.; Malova, Helmi V.; Kislov, Roman A.; Zelenyi, Lev M.; Obridko, Vladimir N.; Kharshiladze, Alexander F.; Tokumaru, Munetoshi; Sokół, Justyna M.; Grzedzielski, Stan; Fujiki, Ken'ichi Bibcode: 2017ApJ...836..108K Altcode: We provide observational evidence for the existence of large-scale cylindrical (or conic-like) current sheets (CCSs) at high heliolatitudes. Long-lived CCSs were detected by Ulysses during its passages over the South Solar Pole in 1994 and 2007. The characteristic scale of these tornado-like structures is several times less than a typical width of coronal holes within which the CCSs are observed. CCS crossings are characterized by a dramatic decrease in the solar wind speed and plasma beta typical for predicted profiles of CCSs. Ulysses crossed the same CCS at different heliolatitudes at 2-3 au several times in 1994, as the CCS was declined from the rotation axis and corotated with the Sun. In 2007, a CCS was detected directly over the South Pole, and its structure was strongly highlighted by the interaction with comet McNaught. Restorations of solar coronal magnetic field lines reveal the occurrence of conic-like magnetic separators over the solar poles in both 1994 and 2007. Such separators exist only during solar minima. Interplanetary scintillation data analysis confirms the presence of long-lived low-speed regions surrounded by the typical polar high-speed solar wind in solar minima. Energetic particle flux enhancements up to several MeV/nuc are observed at edges of the CCSs. We built simple MHD models of a CCS to illustrate its key features. The CCSs may be formed as a result of nonaxiality of the solar rotation axis and magnetic axis, as predicted by the Fisk-Parker hybrid heliospheric magnetic field model in the modification of Burger and coworkers. Title: Magnetic field variations in the umbra of single sunspots during their passage across the solar disk Authors: Zagainova, Iu. S.; Fainshtein, V. G.; Obridko, V. N.; Rudenko, G. V. Bibcode: 2016Ge&Ae..56.1015Z Altcode: Temporal variations of the maximum ( B max) and average (< B>) magnetic inductions, minimum ( α min) and average (< α>) inclination angles of the field lines to the radial direction from the center of the Sun, and areas of the sunspot umbra S in the umbra of single sunspots during their passage across the solar disk are investigated. The variation of the properties of single sunspots has been considered at different stages of their existence, i.e., during formation, the "quiet" period, and the disappearance stage. It has been found that, for the majority of the selected single sunspots, there is a positive correlation between B max and S and between and S defined at different times during the passage of sunspots across the solar disk. It is shown in this case that the nature of the dependence between the parameters α min and B max, α min and S, as well as between < α> and < B>, < α> and S, can vary from sunspot to sunspot, but for many sunspots the inclination angle of the field lines decreases on average with the growth of the sunspot umbra area and the field strength. Title: The Sun and heliosphere explorer - the Interhelioprobe mission Authors: Kuznetsov, V. D.; Zelenyi, L. M.; Zimovets, I. V.; Anufreychik, K.; Bezrukikh, V.; Chulkov, I. V.; Konovalov, A. A.; Kotova, G. A.; Kovrazhkin, R. A.; Moiseenko, D.; Petrukovich, A. A.; Remizov, A.; Shestakov, A.; Skalsky, A.; Vaisberg, O. L.; Verigin, M. I.; Zhuravlev, R. N.; Andreevskyi, S. E.; Dokukin, V. S.; Fomichev, V. V.; Lebedev, N. I.; Obridko, V. N.; Polyanskyi, V. P.; Styazhkin, V. A.; Rudenchik, E. A.; Sinelnikov, V. M.; Zhugzhda, Yu. D.; Ryzhenko, A. P.; Ivanov, A. V.; Simonov, A. V.; Dobrovolskyi, V. S.; Konstantinov, M. S.; Kuzin, S. V.; Bogachev, S. A.; Kholodilov, A. A.; Kirichenko, A. S.; Lavrentiev, E. N.; Pertsov, A. A.; Reva, A. A.; Shestov, S. V.; Ulyanov, A. S.; Panasyuk, M. I.; Iyudin, A. F.; Svertilov, S. I.; Bogomolov, V. V.; Galkin, V. I.; Marjin, B. V.; Morozov, O. V.; Osedlo, V. I.; Rubinshtein, I. A.; Scherbovsky, B. Ya.; Tulupov, V. I.; Kotov, Yu. D.; Yurov, V. N.; Glyanenko, A. S.; Kochemasov, A. V.; Lupar, E. E.; Rubtsov, I. V.; Trofimov, Yu. A.; Tyshkevich, V. G.; Ulin, S. E.; Novikov, A. S.; Dmitrenko, V. V.; Grachev, V. M.; Stekhanov, V. N.; Vlasik, K. F.; Uteshev, Z. M.; Chernysheva, I. V.; Shustov, A. E.; Petrenko, D. V.; Aptekar, R. L.; Dergachev, V. A.; Golenetskii, S. V.; Gribovskyi, K. S.; Frederiks, D. D.; Kruglov, E. M.; Lazutkov, V. P.; Levedev, V. V.; Oleinik, F. P.; Palshin, V. D.; Repin, A. I.; Savchenko, M. I.; Skorodumov, D. V.; Svinkin, D. S.; Tsvetkova, A. S.; Ulanov, M. V.; Kozhevatov, I. E.; Sylwester, J.; Siarkowski, M.; Bąkała, J.; Szaforz, Ż.; Kowaliński, M.; Dudnik, O. V.; Lavraud, B.; Hruška, F.; Kolmasova, I.; Santolik, O.; Šimůnek, J.; Truhlík, V.; Auster, H. -U.; Hilchenbach, M.; Venedictov, Yu.; Berghofer, G. Bibcode: 2016Ge&Ae..56..781K Altcode: The Interhelioprobe mission aims to investigate the inner heliosphere and the Sun from close distances (up to 0.3 AU) and from out of the ecliptic plane (up to 30°). In this paper we present the relevance of the mission and its main scientific objectives, describe the scientific payload, ballistic scenario and orbits of the spacecraft. Possibilities of scientific cooperation with other solar and heliospheric space missions are also mentioned. Title: Properties of solar activity and ionosphere for solar cycle 25 Authors: Deminov, M. G.; Nepomnyashchaya, E. V.; Obridko, V. N. Bibcode: 2016Ge&Ae..56..742D Altcode: Based on the known forecast of solar cycle 25 amplitude ( Rz max ≈ 50), the first assessments of the shape and amplitude of this cycle in the index of solar activity F10.7 (the magnitude of solar radio flux at the 10.7 cm wavelength) are given. It has been found that ( F10.7)max ≈ 115, which means that it is the lowest solar cycle ever encountered in the history of regular ionospheric measurements. For this reason, many ionospheric parameters for cycle 25, including the F2-layer peak height and critical frequency ( hmF2 and foF2), will be extremely low. For example, at middle latitudes, typical foF2 values will not exceed 8-10 MHz, which makes ionospheric heating ineffective in the area of upper hybrid resonance at frequencies higher than 10 MHz. The density of the atmosphere will also be extremely low, which significantly extends the lifetime of low-orbit satellites. The probability of F-spread will be increased, especially during night hours. Title: The phase shift between the hemispheres in the solar activity cycle Authors: Shibalova, A. S.; Obridko, V. N.; Sokoloff, D. D. Bibcode: 2016ARep...60..949S Altcode: The shift between the solar activity cycles in the northern and southern hemispheres of the Sun is studied using data on sunspot number and area. The data obtained are compared with archival information on episodes of appreciable solar-cycle asymmetry. The small phase shift between recent activity cycles in the northern and southern solar hemispheres differs considerably from the shift for episodes of appreciable deviations from dipolar symmetry in the sunspot distribution detected with various degrees of confidence in archival astronomical data from the 17th-19th centuries. The current time shift between the hemispheres is insignificant, about 6-7 months. This shift has changed its sign twice in recent solar history; this probably corresponds to more or less periodic variations with a timescale close to the duration of the Gleissberg cycle. Title: On the negative correlation between solar activity and solar rotation rate Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2016AstL...42..631O Altcode: An increase in solar activity is shown to be accompanied by a decrease in solar rotation rate. This effect has been established from various indices; it manifests itself as cyclic and secular variations in the global magnetic field, in the observations of the magnetic field of the Sun as a star, and in the observations of the solar corona. Some possible explanations of this effect are discussed. Title: A cylindrical current sheet over the South solar pole observed by Ulysses Authors: Khabarova, Olga; Kislov, Roman; Malova, Helmi; Obridko, Vladimir Bibcode: 2016EGUGA..1818076K Altcode: We provide the first evidence for the existence of a quasi-stable cylindrical current sheet over the South solar pole as observed by Ulysses in 2006, near the solar minimum, when it reached maximal heliolatitude of 79.7 degrees at 2.4 AU. It took place inside a fast speed stream from the coronal hole, and the tube was presumably crossed rather far from the center within two degrees of heliolatitude and ~10 degrees of heliolongitude. During the spacecraft passage throughout the structure, the solar wind velocity was approximately twice as little, the solar wind density was 20 times lower than the surrounded plasma values, but the temperature was twice as large in the point closest to the pole. The interplanetary magnetic field (IMF) strongly decreased due to sharp variations in the IMF radial component (RTN) that changed its sign twice, but other components did not show changes out of usual stochastic behavior. Both the behavior of the IMF, rotation of the plasma flow direction and other features indicate the occurrence of cylindrical current sheet. We discuss its solar origin and present modeling that can explain the observations. Title: Long-period geomagnetic pulsations as solar flare precursors Authors: Barkhatov, N. A.; Obridko, V. N.; Revunov, S. E.; Snegirev, S. D.; Shadrukov, D. V.; Sheiner, O. A. Bibcode: 2016Ge&Ae..56..249B Altcode: We compare long-period pulsations of the horizontal component of the geomagnetic field at intervals that precede extreme solar flares. To this end, we use the wavelet-skeleton technique to process the geomagnetic field disturbances recorded at magnetic stations over a wide geographical range. The synchronization times of wavelet-skeleton spectral distributions of long-period pulsations of geomagnetic oscillations over all magnetic stations are shown as normalized histograms. A few days before an intense solar flare, the histograms show extremes. This means that these extremes can be regarded as flare precursors. The same technique is used to analyze the parameters of near-Earth space. The histograms obtained in this case are free of the aforementioned extrema and, therefore, cannot point to an upcoming flare. The goal of this study is to construct a correlation-spectral method for the short-term prediction of solar flare activity. Title: What causes geomagnetic activity during sunspot minimum? Authors: Kirov, B.; Asenovski, S.; Georgieva, K.; Obridko, V. N. Bibcode: 2015Ge&Ae..55.1033K Altcode: 2014arXiv1412.0886K It is well known that the main drivers of geomagnetic disturbances are coronal mass ejections whose number and intensity are maximum in sunspot maximum, and high speed solar wind streams from low latitude solar coronal holes which maximize during sunspot declining phase. But even during sunspot minimum periods when there are no coronal mass ejections and no low latitude solar coronal holes, there is some "floor" below which geomagnetic activity never falls. Moreover, this floor changes from cycle to cycle. Here we analyze the factors determining geomagnetic activity during sunspot minimum. It is generally accepted that the main factor is the thickness of the heliospheric current sheet on which the portion of time depends which the Earth spends in the slow and dense heliospheric current sheet compared to the portion of time it spends in the fast solar wind from superradially expanding polar coronal holes. We find, however, that though the time with fast solar wind has been increasing in the last four sunspot minima, the geomagnetic activity in minima has been decreasing. The reason is that the parameters of the fast solar wind from solar coronal holes change from minimum to minimum, and the most important parameter for the fast solar wind's geoeffectivity—its dynamic pressure—has been decreasing since cycle 21. Additionally, we find that the parameters of the slow solar wind from the heliospheric current sheet which is an important driver of geomagnetic activity in sunspot minimum also change from cycle to cycle, and its magnetic field, velocity and dynamic pressure have been decreasing during the last four minima. Title: Leading and following sunspots: their magnetic properties and ultra-violet emission above them Authors: Zagainova, Iu. S.; Fainshtein, V. G.; Obridko, V. N. Bibcode: 2015arXiv151107229Z Altcode: Using SDO/HMI and SDO/AIA data for sunspot groups of the 24th solar cycle, we analyzed magnetic properties and He II 304 emission in leading and following sunspots separately. Simultaneous examination of umbral magnetic properties and atmospheric characteristics above the umbrae draws on average differences in He II 304 contrast over the umbrae of leading and following spots we discovered earlier for solar cycle 23 sunspot groups based on SOHO data as well as on the hypothetical relationship between contrast asymmetry and magnetic field asymmetry in umbrae. We use a more accurate and faster algorithm for solving the pi-uncertainty problem of the transverse magnetic field direction in this research producing new results on differences in magnetic field properties between magneto-conjugated leaders and followers. We found that, in ~78% of the cases, the minimum (over the umbra area) angle between the magnetic field line and the normal to the solar surface, a_min, is smaller in the leading spots, so the magnetic field there is more vertical than that in the counterpart following spot. It was also found that umbral area-averaged angle <a> in ~83% of the spot groups examined is smaller in the leader compared to the follower and the maximum and mean magnetic flux densities inside the umbra depend on the umbral area. Title: The relative role of space weather factors in Chizhevsky Velkhover effect Authors: Gromozova, E.; Rudenchik, E.; Ragulskaya, M.; Obridko, V.; Hramova, E. Bibcode: 2015simi.conf...96G Altcode: The Astrobiological Chizhevsky–Velkhover effect occupies a special place among biological effects, concerned with solar activity. It's about the color change of structure elements (volyutin granules) of bacterium sells at staining by methylene blue solution (metachromasia reaction). Today the volyutin granules, consisting of inorganic polyphosphate, were observed at procaryotes, lower eukaryotes, at protozoa, and as phosphatic pellets in platelets of higher organisms (including human).

According to the discoverers, volyutin granules color change depends on solar activity. But since 1934 new data about structure of solar-earth relations were observed, and the solar dynamics changed. Cosmic weather factors having the dominating influence on etalon sell structures in 2000 – 2013 are discussed in the report. Title: The Upper Limit of Sunspot Activity as Observed over a Long Time Interval Authors: Nagovitsyn, Yu. A.; Obridko, V. N.; Kuleshova, A. I. Bibcode: 2015SoPh..290.1285N Altcode: 2015SoPh..tmp...23N After analyzing the observational manifestations of the α- and ω-effects of the dynamo theory and using the modified Waldmeier rule, we show that the annual mean Wolf numbers at the maximum of the 11-year cycle that are likely to occur a time interval of 104 years have an upper limit amounting approximately to WEXTR∼230 - 240. Similar values were also obtained using the results by Usoskin et al. (2014, Astron. Astrophys. 562, L10), who considered the probability of various activity levels by reconstructing the variations of solar activity over three thousand years. As an additional result, the predicted maximum of Cycle 24 is refined and is shown to be WM=72 - 132 with a 95 % confidence. Title: A comparative analysis of the properties of the magnetic fields in leading and trailing sunspots Authors: Zagainova, Yu. S.; Fainshtein, V. G.; Rudenko, G. V.; Obridko, V. N. Bibcode: 2015ARep...59..156Z Altcode: Pairs of leading and trailing sunspots whose umbrae are joined by magnetic-field lines have been selected based on calculations using SOLIS magnetic-field data in a potential approximation and the B d technique of Rudenko, together with SDO data for 2010-2013. The shape of the field lines reflects to some extent the shape of the magnetic tube connecting the leading and trailing spots. The minimum angle between the field lines and the radial direction a min, the maximum magnetic field B max, the length of the field line from the leading spot to the apex, where the radial component of the field is zero, L l , and the length of the field line from the apex to its eastern base L f are determined in the umbrae of all the selected sunspots. In ∼81% of cases, a min is smaller in the leading spot than in the trailing spot. For such sunspots, there is a positive correlation between these angles in the leading and trailing spots. The dependences of a min on the areas of the umbrae in the leading and trailing spots are different. There is a weak negative correlation between a min and B max. In other words, on average, the field lines are closer to radial in magnetic tubes forming the umbrae of both leading and trailing spots with stronger fields at the photospheric level. In ∼60-65% of cases, the section of the field adjacent to the leading spot L l is shorter than L f . Similar results are obtained for large single spots. Title: Comparison of the properties of leading and trailing sunspots Authors: Zagainova, Yu. S.; Fainshtein, V. G.; Obridko, V. N. Bibcode: 2015Ge&Ae..55...13Z Altcode: The magnetic properties of leading and trailing sunspots were compared based on SDO/HMI and SDO/AIA data with a high spatial resolution for the growth phase and maximum of cycle 24. The properties of the solar atmosphere above sunspots are also discussed independently for both of these sunspot types. It was shown that the contrast in the He II 304 ( C 304) line above the umbra of leading and single sunspots is on average smaller than such a contrast above the umbra of trailing sunspots and on average weakly depends on the umbra area for both C 304 sunspot types. It was established that the minimal angle between the field direction and the normal to the solar surface at the field measurement site is smaller in leading sunspots than in trailing ones (αmin - ls < αmin - fs ) in 84% of the considered magnetically connected "leading-trailing" sunspot pairs, and a positive correlation exists between angles αmin - ls and αmin - fs . It was found that the C 304 contrast increases with decreasing αmin - ls, fs for leading and trailing sunspots, and the C 304 - ls / C 304 - fs ratio on average decreases with increasing αmin - ls min - fs ratio. The dependences of the maximal and average magnetic induction values in an umbra on the umbra area were constructed for the first time and compared independently for leading and trailing sunspots. It was concluded that the maximal and average magnetic field values do not vanish when the umbra area decreases to very small values. In all cases the magnetic field in leading and single sunspots is larger than in trailing ones. Title: Coronal Holes in Global Complexes of Activity Authors: Obridko, Vladimir N.; Shelting, Bertha D. Bibcode: 2015AdAst2015E...7O Altcode: No abstract at ADS Title: Role of the large-scale solar magnetic field structure in the global organization of solar activity Authors: Ivanov, E. V.; Obridko, V. N. Bibcode: 2014Ge&Ae..54..996I Altcode: The relation of the large-scale solar magnetic field structure to the most pronounced manifestations of solar activity (filaments, active regions, sunspots, coronal mass ejections, and coronal holes) has been studied. Title: Cyclic and secular variations sunspot groups with various scales Authors: Obridko, V. N.; Badalyan, O. G. Bibcode: 2014ARep...58..936O Altcode: Data from the Greenwich Catalog and its NOAA-USEF extension are used to analyze the spot-formation activity on the Sun separately for small ( S < 100 msh), medium (100 < S < 500 msh), and large ( S > 500 msh) sunspot groups. The relationship between the numbers of groups with various areas changes with time. This is determined primarily by numerous small-area groups. Over nearly 150 years, periods have been observed when the relative number of large groups has increased (Cycles 18 and 19), as well as extensive periodswhen the number of small groups has grown. As a rule, the latter correspond to low activity cycles. The observed relations indicate the possible interaction of two independent mechanisms in the spot-formation activity of the Sun. A deep dynamo controls the variations of the number of small spots, while the formation of large spots is determined by processes in sub-surface layers. Title: North-South Asymmetry in the Distribution of Solar Background Magnetic Field Authors: Obridko, V. N.; Chertoprud, V. E.; Kuzanyan, K. M. Bibcode: 2014SoPh..289.2867O Altcode: 2014SoPh..tmp...58O The aim of this article is to investigate how the background magnetic field of the Sun behaves in different hemispheres. We used SOHO/MDI data obtained during a period of eight years from 2003 to 2011 to analyze the intensity distribution of the background magnetic field over the solar surface. We find that the background fields of both polarities (signs) are more intense in the southern than in the northern hemisphere. Mixed polarities are observed in the vicinity of the equator. In addition to the main field, a weaker field of opposite polarity is always present in the polar regions. In the declining phase of the cycle, the main field dominates, but at the minimum and in the rising phase of the cycle, it is gradually replaced by the growing stronger secondary field. Title: Cosmic ray modulation during the solar activity growth phase of cycle 24 Authors: Gushchina, R. T.; Belov, A. V.; Eroshenko, E. A.; Obridko, V. N.; Paouris, E.; Shelting, B. D. Bibcode: 2014Ge&Ae..54..430G Altcode: Recent years allowed us to study long-term variations in the cosmic ray (CR) intensity at an unusually deep solar activity (SA) minimum between cycles 23 and 24 and during the SA growth phase in cycle 24, which was the cycle when SA was the lowest for the epoch of regular ground-based CR observations since 1951. The intensity maximum, the value of which depends on the particle energy, was observed in CR variations during the period of an unusually prolonged SA minimum: the CR density during the aformentioned period (2009) is higher than this density at previous CR maxima in cycles 19-23 for low-energy particles (observed on spacecraft and in the stratosphere) and medium-energy particles (observed with neutron monitors). After 2009 CR modulation at the SA growth phase was much weaker over three years (2010-2012) than during the corresponding SA growth periods in the previous cycles. The possible causes of this anomaly in CR variations, which are related to the CR residual modulation value at a minimum between cycles 23 and 24 and to variations in SA characteristics during this period, were examined. The contribution of different solar magnetic field characteristics and indices, taking into account sporadic solar activity, has been estimated. Title: Comparative Characteristics of the Leading and Following Sunspots Authors: Zagainova, Yu. S.; Fainshtein, V. G.; Obridko, V. N. Bibcode: 2014ATsir1612....1Z Altcode: Magnetic characteristics of the leading and following sunspots are compared using SDO/HMI and SDO/AIA high-resolution data, and the properties of the solar atmosphere over sunspots are discussed separately for each category of sunspots. Title: Global Complexes of Activity Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2014simi.conf....4O Altcode: A new concept of Global Complexes of Activity's on the Sun is presented, which brings together objects associated with both global and local fields in a single framework. Activity complexes have traditionally been identified purely from observations of active regions. We show here that a global complex also includes coronal holes and active regions. Our analysis is based on a large dataset on magnetic fields on various scales, SOHO/MDI observations of active regions and magnetic fields, and UV observations of coronal holes. It is shown that the evolution of coronal holes and active regions are parts of a single process. The relationships between the fields of different scales during the generation of the cycle is discussed. Title: Cosmic factors of evolution of biosphere and geosphere. (review of the Interdisciplinary colloquium, May 21-23) Authors: Obridko, V. N. Bibcode: 2014simi.conf...25O Altcode: Main topics. Connection to the SCOSTEP international program VarSITI. The young Sun: paradoxes and hypotheses. A review of ideas of life origin: from ancient times to the present day. The early stages of life evolution: archaeon, early proterozoic. Evolution of biosphere. The role of climate-ecosystems interaction in climate response to exterior impact. Geomagnetic reversal, its properties, causes, possible impact on biosphere. Cosmic rays as a factor of biosphere evolution, An estimate of the extreme energy of flares from the theoretical point of view. Estimation of the maximal height of solar cycle. The Maunder Minimum, its main characteristics and hypotheses of its origin. Live organism adjustment to cosmic factors impact: problems and prospective research. Title: The Relative Umbral Area in Spot Groups as an Index of Cyclic Variation of Solar Activity Authors: Bludova, N. G.; Obridko, V. N.; Badalyan, O. G. Bibcode: 2014SoPh..289.1013B Altcode: The Greenwich series of data was used to study the ratio [q] of the total umbra area to the total area of the sunspot group (for brevity "relative umbral area") for the period 1874 - 1976. It was revealed that the annual mean value of q varied in time from 0.15 to 0.28 and reached its maximum in the early 1930s. The dependence of q on the sunspot group area [S] was considered to show that the smallest groups, of area less than 100 m.v.h. (millionths of the visible hemisphere), contributed most significantly to the temporal variation of q. In contrast to the earlier results, the dependence obtained proved to be rather complicated. The coefficients of the linear expansion q(S) are themselves dependent on the sunspot-group area and time [t]; i.e. the relation of q to both S and t is nonlinear. Only in sunspot groups with a large area does dependence disappear, and q becomes constant, equal to 0.18. This is the value given in textbooks. The relations obtained show that the relive umbral area and the relative number of small groups are important parameters of the secular variation of solar activity. In particular, they may account for variations in the mean magnetic field in active regions, the complexity of a group according to the magnetic classification, the flare activity of a sunspot group, and its geophysical impact. It is conjectured that the parameter q describes the time-varying relative contribution from the interior and subsurface dynamo mechanisms. Title: Coronal holes and global complexes of activity Authors: Obridko, Vladimir; Shelting, Bertha Bibcode: 2014cosp...40E2335O Altcode: A new concept of the “Global Complexes of Activity” is presented, which brings together the objects of both global and local fields. For a long time, the complexes of activity were traditionally identified only from observations of active regions. In this paper we show that a global complex includes also coronal holes and active regions. The analysis is based on a large set of data on magnetic fields of various scales, SOHO/MDI observations of active regions and magnetic fields, and UV observations of coronal holes. It is shown that the evolution of coronal holes and active regions is a single process. Discussed is the relationship between the fields of different scales in the process of cycle generation Title: Transport of particles in the low- and high-energy solar wind from the Sun to the Jupiter orbit Authors: Khabarova, Olga; Obridko, Vladimir; Zharkova, Valentina Bibcode: 2014cosp...40E1456K Altcode: In this report a comparison between the low- and high-energy solar wind as seen from the multi-satellite observations is presented combined with some effects of the large-scale structure interplanetary magnetic field (IMF) on particle transport in the inner heliosphere. We will present a comparison of the low-energy solar wind near the ecliptic plane with those at high latitudes, at least up, to the Jupiter’s orbit. The behaviour of solar wind particles in the low-energy range up to 10 keV is determined by the solar wind expansion from the Sun, and strongly depends on the quasi-stationary distribution of the interplanetary magnetic field (IMF). At the same time, the origin and dynamics of high-energy solar particles (with energies >10 keV) at heliocentric distances up to 1 AU are not significantly impacted by this quasi-stationary interplanetary magnetic field. We explore the contributions to the solar wind of impulsive SEP events from flares in comparison with gradual SEP events, which can fill a big part of the inner heliosphere. We will argue that transport of particles through the heliosphere in the gradual SEP events can be affected by the IMF variations caused by either small-scale processes like magnetic turbulence often present in the interplanetary space or by a deviation of the IMF from the classic model predictions. Observations show that a decrease of the IMF radial component with distance has a slope of -5/3 instead of -2 predicted by Parker’s model. We explore a few possible reasons for this deviations and their impact on the characteristics of the solar wind particles. Title: What causes geomagnetic activity during sunspot minimum? Authors: Kirov, Boian; Obridko, Vladimir; Asenovski, Simeon Bibcode: 2014cosp...40E1502K Altcode: Since the beginning of the geomagnetic measurements, the variations in the geomagnetic field have been related to solar activity. It is now known that big sporadic (non-recurrent) geomagnetic storms are caused by coronal mass ejections. The coronal mass ejections are related to the solar toroidal field whose manifestation are sunspots, so during sunspot maximum there is also a maximum in geomagnetic activity. Another source of geomagnetic activity are the coronal holes - open unipolar magnetic field areas from which the high speed solar wind emanates. Disturbances caused by high speed solar wind are maximum during the sunspots declining phase, which leads to two geomagnetic activity maxima in the 11-year sunspot cycle. In sunspot minimum, even during long periods without sunspots and without low-latitude coronal holes, geomagnetic disturbances are still observed. In the present work we analyze the geomagnetic activity during sunspot minimum, its sources and the reasons for its cyclic variations. Title: Solar activity over different timescales Authors: Obridko, Vladimir; Nagovitsyn, Yuri Bibcode: 2014cosp...40E2334O Altcode: The report deals with the “General History of the Sun” (multi-scale description of the long-term behavior of solar activity): the possibility of reconstruction. Time scales: • 100-150 years - the Solar Service. • 400 - instrumental observations. • 1000-2000 years - indirect data (polar auroras, sunspots seen with the naked eye). • Over-millennial scale (Holocene) -14C (10Be) Overview and comparison of data sets. General approaches to the problem of reconstruction of solar activity indices on a large timescale. North-South asymmetry of the sunspot formation activity. 200-year cycle over the “evolution timescales”.The relative contribution of the large-scale and low-latitude. components of the solar magnetic field to the general geomagnetic activity. “Large-scale” and low-latitude sources of geomagnetic disturbances. Title: Large-scale properties of the solar wind in the inner heliosphere Authors: Khabarova, Olga; Obridko, Vladimir; Zharkova, Valentina; Veselov, Mikhail Bibcode: 2014cosp...40E1457K Altcode: Since the solar wind phenomenon has been revealed and confirmed, one of the most intriguing problems was to understand processes in the solar atmosphere and their relation with the solar wind characteristics at different distances from the Sun. Analysis of multi-spacecraft measurements of plasma parameters and the interplanetary magnetic field provides us with knowledge about the heliosphere from global to small scales. Comparisons of observations with models, describing small-scale processes, usually give more positive results than in the case of models comparison with the solar wind properties at the scales larger than several proton gyroradii. For example, Parker-like models face with big problems in their attempts to predict the solar wind plasma and, especially, the behaviour of the interplanetary magnetic field. Observations show that the radial component of the interplanetary magnetic field depends on heliolatitude and radially decreases with a slope of -5/3 instead of the predicted slope of -2 (Khabarova, Obridko, ApJ, 2012; Khabarova, Astronomy Reports, 2013). This may be determined by small-scale processes occurring in some vicinity of the heliospheric current sheet and related to the magnetic reconnection (Zharkova, Khabarova, ApJ, 2012). In this report we present results of data analysis of eight spacecraft to study variations of plasma, the electric and magnetic field with distance and heliolatitude. begin{enumerate}

Zharkova V., Khabarova O., Particle Acceleration in the Reconnecting Heliospheric Current Sheet: Solar Wind Data Versus 3D PIC Simulations, Astrophysical Journal, 2012, V.752, 1, 35 doi:10.1088/0004-637X/752/1/35 begin{enumerate} Khabarova Olga, and Obridko Vladimir, Puzzles of the Interplanetary Magnetic Field in the Inner Heliosphere, 2012, Astrophysical Journal, 761, 2, 82, doi:10.1088/0004-637X/761/2/82 begin{enumerate} Khabarova Olga V., The interplanetary magnetic field: radial and latitudinal dependences. Astronomy Reports, 2013, Vol. 57, No. 11, pp. 844-859, DOI: 10.1134/S1063772913110024 Title: Long-term variations of geomagnetic activity and their solar sources Authors: Kirov, B.; Obridko, V. N.; Georgieva, K.; Nepomnyashtaya, E. V.; Shelting, B. D. Bibcode: 2013Ge&Ae..53..813K Altcode: 2013arXiv1307.7960K Geomagnetic activity in each phase of the solar cycle consists of 3 parts: (1) a "floor" below which the geomagnetic activity cannot fall even in the absence of sunspots, related to moderate graduate commencement storms; (2) sunspot-related activity due to sudden commencement storms caused by coronal mass ejections; (3) graduate commencement storms due to high speed solar wind from solar coronal holes. We find that the changes in the "floor" depend on the global magnetic moment of the Sun, and on the other side, from the height of the "floor" we can judge about the amplitude of the sunspot cycle. Title: Global complexes of activity Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2013ARep...57..786O Altcode: A new concept of "Global Complexes of Activity" on the Sun is presented, which brings together objects associated with both global and local fields in a single framework. Activity complexes have traditionally been identified purely from observations of active regions. We show here that a global complex also includes coronal holes and active regions. Our analysis is based on a large dataset on magnetic fields on various scales, SOHO/MDI observations of active regions and magnetic fields, and UV observations of coronal holes. It is shown that the evolution of coronal holes and active regions are parts of a single process. The relationships between the fields on different scales during the generation of the cycle is discussed. Title: Dependence of the solar wind speed on the coronal magnetic field in cycle 23 Authors: Lotova, N. A.; Obridko, V. N. Bibcode: 2013AstL...39..474L Altcode: The dependence of the position of the solar wind sonic point on the magnetic field in the solar corona during cycle 23 is studied. This dependence is shown to be rather strong in the rising phase and at the cycle maximum. As the coronal magnetic field grows, the distance to the sonic point decreases. Since the distance to the sonic point has been shown previously to anticorrelate with the solar wind speed, the result obtained suggests a strong positive correlation between the later and the coronal magnetic field. The situation changed dramatically two years after the calendar date of the cycle maximum. Beginning in 2004 the solar wind speed ceased to depend on the magnetic field up until the cycle minimum in December 2008. In 2009 a strong dependence of the wind speed on the coronal magnetic field was restored. It is hypothesized that this effect is associated with two different coronal heating mechanisms whose relative efficiency, in turn, depends on the contribution from magnetic fields of different scales. Title: Cyclic and secular variations of the inner structure of sunspot groups Authors: Obridko, V. N.; Badalyan, O. G.; Bludova, N. G. Bibcode: 2013simi.confE..37O Altcode: No abstract at ADS Title: Co-evolution of the Sun and of life on Earth Authors: Obridko, V.; Ragulskaya, M.; Rudenchik, E.; Hramova, E. Bibcode: 2013simi.confE..42O Altcode: No abstract at ADS Title: Solar activity and geomagnetic disturbances Authors: Obridko, V. N.; Kanonidi, Kh. D.; Mitrofanova, T. A.; Shelting, B. D. Bibcode: 2013Ge&Ae..53..147O Altcode: An analysis of IZNIRAN magnetic observatory data indicated that geomagnetic storms with sudden and gradual commencements form two independent populations with respect to the disturbance occurrence time and character because the solar sources of these disturbances are different. Storms with sudden and gradual commencements are caused by coronal mass ejections and high-speed solar wind streams from coronal holes, respectively. Title: Cosmic Ray Modulation At The Solar Activity Minimum And Ascending Phase In The 24Th Cycle Authors: Gushchina, R.; Belov, A.; Eroshenko, E.; Obridko, V.; Shelting, B. Bibcode: 2013ICRC...33.3680G Altcode: . Recent years have given us the opportunity to explore the long-term behavior of the cosmic ray (CR) intensity in the unusually deep solar activity (SA) minimum between the 23rd and the 24th cycles and during the ascending phase of the SA in the 24th cycle, the lowest cycle over the history of regular observations of cosmic rays. During the unusually prolonged minimum SA in CR observed maximum CR intensity (in 2009) exceeds the previous maximums value of CR in 19-23 cycles for small energy particles (observed by satellites and stratosphere) and medium energy (observed by neutron monitors). After 2009, the CR modulation in the phase of growth of the SA for three years (20 10-2012) are much weaker than the modulation in the corresponding periods of the previous cycles SA. Some possible reasons for this anomalies in CR variations are discussed. Title: Puzzles of the Interplanetary Magnetic Field in the Inner Heliosphere Authors: Khabarova, Olga; Obridko, Vladimir Bibcode: 2012ApJ...761...82K Altcode: 2012arXiv1204.6672K Deviations of the interplanetary magnetic field (IMF) from Parker's model are frequently observed in the heliosphere at different distances r from the Sun. Usually, it is supposed that the IMF behavior corresponds to Parker's model overall, but there is some turbulent component that impacts and disrupts the full picture of the IMF spatial and temporal distribution. However, the analysis of multi-spacecraft in-ecliptic IMF measurements from 0.29 AU to 5 AU shows that the IMF radial evolution is rather far from expected. The radial IMF component decreases with the adiabatic power index (|Br | vprop r -5/3), the tangential component |Br| vprop r -1, and the IMF strength B vprop r -1.4. This means that the IMF is not completely frozen in the solar wind. It is possible that turbulent processes in the inner heliosphere significantly influence the IMF expansion. This is confirmed by the analysis of the Br distribution's radial evolution. Br has a well-known bimodal histogram only at 0.7-2.0 AU. The bimodality effect gradually disappears from 1 AU to 4 AU, and Br becomes quasi-normally distributed at 3-4 AU (which is a sign of rapid vanishing of the stable sector structure with heliocentric distance). We consider a quasi-continuous magnetic reconnection, occurring both at the heliospheric current sheet and at local current sheets inside the IMF sectors, to be a key process responsible for the solar wind turbulization with heliocentric distance as well as for the breakdown of the "frozen-in IMF" law. Title: Coronal Mass Ejections and the Index of Effective Solar Multipole Authors: Obridko, V. N.; Ivanov, E. V.; Özgüç, A.; Kilcik, A.; Yurchyshyn, V. B. Bibcode: 2012SoPh..281..779O Altcode: 2012SoPh..tmp..199O The paper considers the relationship between the cyclic variations in the velocity of coronal mass ejections (CME) and the large-scale magnetic field structure (LSMF) in cycles 21 - 23. To characterize a typical size of the LSMF structure, we have used the index of the effective solar multipole (ESMI). The cyclic behavior of the CME occurrence rate and velocity proved to be similar to that of ESMI. The hysteresis observed in variations of the CME maximum velocity is interpreted as a manifestation of different contributions from the two field structures (local and global magnetic fields) in different phases of the 11-year activity cycle. It is suggested that cyclic variations in the maximum velocity of coronal mass ejections are due to different conditions for the formation of the complexes of active regions connected by coronal arch systems, which are the main source of high-velocity CMEs. Title: Puzzles of the Interplanetary Magnetic Field in the Inner Heliosphere Authors: Khabarova, O.; Obridko, V. Bibcode: 2012AGUFMSH13A2223K Altcode: Deviations of the interplanetary magnetic field (IMF) from Parker's model are frequently observed in the heliosphere at different distances r from the Sun. Usually, it is supposed that the IMF behavior corresponds to Parker's model as a whole, but there is some turbulent component that impacts the full picture of the IMF spatial and temporal distribution and damages it. However, the analysis of multi-spacecraft in-ecliptic IMF measurements from 0.29 AU to 5 AU shows that the IMF radial evolution is rather far from expected. The radial IMF component decreases with the adiabatic power index (|Br|~r^-5/3), the tangential component |Bt|~r^-1.1 and, the IMF strength B~r^-1.4. This means that the IMF is not completely frozen in the solar wind. Possibly, turbulent processes in the inner heliosphere significantly influence the IMF expansion. This is confirmed by the analysis of the Br distribution's radial evolution. Br has a well-known bimodal histogram's view only at 0.7-2.0 AU. The bimodality effect gradually disappears from 1 to 4 AU, and Br becomes quasi-normally distributed at 3-4 AU (which is a sign of rapid vanishing of the stable sector structure with heliocentric distance). We consider a quasi-continuous magnetic reconnection, occurring both at the heliospheric current sheet and at local current sheets inside the IMF sectors, as a key process responsible for the solar wind turbulization with heliocentric distance as well as for the break of the "frozen-in IMF" law. Title: Potential effects of solar and geomagnetic variability on terrestrial biological systems Advances Authors: Babayev, E. S.; Crosby, N. B.; Obridko, V. N.; Rycroft, M. J. Bibcode: 2012asst.book..329B Altcode: No abstract at ADS Title: Global magnetic fields: variation of solar minima Authors: Tlatov, Andrey G.; Obridko, Vladimir N. Bibcode: 2012IAUS..286..113T Altcode: The topology of the large-scale magnetic field of the Sun and its role in the development of magnetic activity were investigated using H α charts of the Sun in the period 1887-2011. We have considered the indices characterizing the minimum activity epoch, according to the data of large-scale magnetic fields. Such indices include: dipole-octopole index, area and average latitude of the field with dominant polarity in each hemisphere and others. We studied the correlation between these indices and the amplitude of the following sunspot cycle, and the relation between the duration of the cycle of large-scale magnetic fields and the duration of the sunspot cycle.

The comparative analysis of the solar corona during the minimum epochs in activity cycles 12 to 24 shows that the large-scale magnetic field has been slow and steadily changing during the past 130 years. The reasons for the variations in the solar coronal structure and its relation with long-term variations in the geomagnetic indices, solar wind and Gleissberg cycle are discussed.

We also discuss the origin of the large-scale magnetic field. Perhaps the large-scale field leads to the generation of small-scale bipolar ephemeral regions, which in turn support the large-scale field. The existence of two dynamos: a dynamo of sunspots and a surface dynamo can explain phenomena such as long periods of sunspot minima, permanent dynamo in stars and the geomagnetic field. Title: Extrema of long-term modulation of the cosmic ray intensity in the last five solar cycles Authors: Gushchina, R. T.; Belov, A. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2012Ge&Ae..52..438G Altcode: Modulation of galactic cosmic rays in cycles 19-23 of solar activity has been determined based on observations of their long-term variations on the ground and in the near-Earth space. The extreme values of long-term variations in cosmic rays, obtained from the data of continuous cosmic radiation monitoring on the ground and in the near-Earth space in the last five solar cycles, have been analyzed. The results are compared with the extrema in the characteristics of solar magnetic fields and the sunspot numbers in these cycles. The similarities and differences in cosmic ray modulation between different cycles are discussed. Title: Sun evolution as a astrobiology factor of life evolution Authors: Ragulskaya, Maria; Obridko, Vladimir Bibcode: 2012cosp...39.1555R Altcode: 2012cosp.meet.1555R The report emphasizes the need to consider the evolution dynamics of Sun modeling of formation and development of life for the astrobiology problems. The life processes occurring within ancient environments, not only depended on stress factors (e.g. temperature, pressure, pH and chemicals), but especially on the type of emission spectrum of the early sun and extreme intensity of cosmic rays. 4 billion years ago the early Sun was significantly different from the current state of the main star of our planetary system. The intensity of the Sun in X-ray and ultraviolet spectral regions was much higher in the modern age than in the era of the formation of life, as shown by IZMIRAN investigations, 2011 (no the total luminosity was about 70% from the current level). Solar activity was also more intensive and chaotic. The intensity of cosmic rays exceeds the current level by several orders of magnitude. It is known that cosmic rays are a powerful factor of evolution, but their excess leads to the destruction biological systems. Perhaps the time of appearance of life was determined at the moment of transition of solar activity at a more orderly functioning. Therefore, the evolutionary dynamics of the Sun must be taken into account to construct models of the earth's life in extreme environments, as well as the construction of displacement models of life within the solar system. Title: Experimental observations of the interplanetary magnetic field distribution in the inner heliosphere: controversial points Authors: Khabarova, O. V.; Obridko, V. N. Bibcode: 2012EGUGA..14.9383K Altcode: Interplanetary magnetic field (IMF) deviations from a Parker spiral are very often observed in the heliosphere at different distances from the Sun. Commonly, it is supposed that the IMF in the inner heliosphere corresponds to the Parker theory as a whole, but there is some turbulent component that impacts a full picture of the IMF spatial and temporal distribution and damages it. Meanwhile, the analysis of multipoint in-ecliptic IMF measurements from 0.23 AU to 5 AU shows that the radial IMF component in the inner heliosphere corresponds neither r-2 law nor the helicity assumption even under rough average. The next problematic point is an explanation of observational results on the in-ecliptic IMF distribution shape at different AU. It is shown that a bimodal (two-humped) view of Br, RTN (or Bx, By, GSE) distribution, well-known at 1 AU, is most brightly expressed at low heliolatitudes at 0.7-2 AU, but it disappears with an increasing heliocentric distance. The in-ecliptic IMF distribution shape becomes perfectly Gaussian-like at 3-4 AU. Such behaviour of the in-ecliptic IMF can not be explained by any theory of the IMF extension in space. Therefore, experimental results, accumulated for the space era, demonstrates the barest necessity of the 3-D interplanetary magnetic field picture revisiting, looking for new theories of plasma and IMF expansion from the Sun, as well as further development of new models of the inner heliosphere. Title: Dynamics of the photospheric magnetic field in the vicinity of the solar equator Authors: Obridko, V. N.; Chertoprud, V. E. Bibcode: 2012ARep...56..146O Altcode: 2012AZh....89..173O SOHO-MDI daily magnetic field synoptic data (a 14-year series of daily maps of the solar magnetic field intensity B available at the site http://soi.stanford.edu/magnetic/index5.html) have been used to analyze the dynamics of the photospheric magnetic field in the vicinity of the solar equator. The standard deviation s B of the field B calculated over areas of tens of square degrees on the solar disk was taken as a basic index. An 11-year variation similar to that observed at higher latitudes is observed in the vicinity of the equator, and is similar for weak and strong fields; i.e., the solar cycle exists in the sunspot-free zone. New qualitative data support the idea that the weak background magnetic field increases toward the solar limb. This angular dependence suggests the existence of a transverse component of the background field. The magnetic fields in the vicinity of the equator were significantly different in the initial phases of Cycles 23 and 24. Annual variations of s B were observed near the center of the solar disk. These variations are due to two factors: the annual variation of the distance from the equator to the disk center and the increase of s B with with distance from the equator. Reliable detection of these variations is an evidence of high accuracy of the s B estimates. Title: The Unusual Sunspot Minimum: Challenge to the Solar Dynamo Theory Authors: Obridko, V. N.; Nagovitsyn, Yu. A.; Georgieva, Katya Bibcode: 2012ASSP...30....1O Altcode: 2012snc..book....1O The last cycle 23 was low, long, complex, and very unusual. The "peculiarity" of the minimum was that the field was weak, but also that the morphology of the heliosphere was very complex. A large number of features of intermediate scale—neither global nor local—were observed. There are reasons to believe that the amplitude and the period of a cycle are determined by the large-scale meridional circulation which, in turn, may be modulated by planetary tidal forces. There are evidences that at present the deep meridional circulation is very slow, from which a low and late maximum of cycle 24 can be predicted. Calculations of the planetary tidal forces indicate that cycle 25 will be still lower, and therefore cycle 24 is the beginning of a secular solar activity minimum. Various prediction methods are summarized, all indicating that we are entering a period of moderately low activity, and the possibility of a Maunder-type minimum is very small. Arguments are also presented in favor of a near-surface dynamo. Title: Scenario of Evolution of the Epoch of Minimum at the Final Stage of Cycle 23 Authors: Lotova, N. A.; Obridko, V. N. Bibcode: 2012ASSP...30..179L Altcode: 2012snc..book..179L The paper is devoted to the study of 11-year cycles of solar activity with an emphasis on the peculiar features observed at the final stage of Cycle 23. The study is based on information on the solar wind stream structure and its relation to the solar wind sources in the corona. Title: The Sun: New Challenges Authors: Obridko, Vladimir N.; Georgieva, Katya; Nagovitsyn, Yury A. Bibcode: 2012ASSP...30.....O Altcode: 2012snc..book.....O No abstract at ADS Title: Magnetohydrostatic model for a coronal hole Authors: Obridko, V. N.; Solov'ev, A. A. Bibcode: 2011ARep...55.1144O Altcode: 2011AZh....88.1238O A model treating a solar coronal hole as an axially symmetrical magnetic formation that is in equilibrium with the surrounding medium is proposed. The model is applicable in the lower corona (to heights of the order of several hundreds of Mm), where the influence of the solar-wind outflow on the state of the system can still be neglected. The magnetic field of the coronal hole is comprised of a relatively weak open flux that varies with height, which extends into interplanetary space, and a closed field, whose flux closes at the chromosphere near the coronal hole. Simple analytical formulas are obtained, which demonstrate for a given equilibrium configuration of the plasma and field the main effect of interest—the lowering of the temperature and density of the gas in the coronal hole compared to their values in the corona at the same geometric height. In particular, it is shown that, at heights of several tens of Mm, the temperature and density of the plasma in the coronal hole are roughly half the corresponding values at the same height in the corona, if the cross-sectional radius of the hole exceeds the scale height in the corona by roughly a factor of 1.5: R h ≈ 1.5 H( T 0). In the special case when R h ≈ H( T 0), the plasma temperature in the hole is equal to the coronal temperature, and the darkening of the coronal hole is due only to an appreciable reduction of the plasma density in the hole, compared to the coronal density. An analogy of the properties of coronal holes and sunspots is discussed, based on the similarity of the magnetic structures of these formations. In spite of the fundamental difference in the mechanisms for energy transport in coronal holes and sunspots, the equilibrium distributions of the plasma parameters in these formations are determined only by the magnetic and gravitational forces, giving rise to a number of common properties, due to their similar magnetic structures. Title: TAHOMAG - vector-magnetograph for INTERHELIOPROBE Authors: Kozhevatov, I. E.; Obridko, V. N.; Rudenchik, E. A. Bibcode: 2011sdmi.confE..75K Altcode: Presented is the design of TAHOMAG - a vector-magnetograph for the INTERHELIOPROBE space mission. Since the instrument is supposed to conduct measurements under the conditions of strongly changing spacecraft velocity with respect to the Sun, we have chosen the scheme of a magnetograph with a spectrograph. A part of the spectrum of length 6Å is fixed in the vicinity of the FeI 6302 Å line. The contours of the Stokes parameters are recorded with a high spectral resolution. The polarization analyzer does not have mobile parts. The spatial resolution in the vicinity of the perihelion (0.3 a.u.) is expected to be 50-75 km. Title: North-South asymmetry of the sunspot indices and its quasi-biennial oscillations Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 2011NewA...16..357B Altcode: The space-time distribution of asymmetry in the area and total number of sunspot groups was considered over the time interval 1874-2009. The time behavior of the asymmetry in these indices of sunspot activity was shown to be similar on both small and large time scales. Spectral variation analysis (SVAN) was applied to study the spectral characteristics. Quasi-biennial oscillations (QBO) were revealed in the asymmetry of both indices under discussion. The SVAN diagrams for the asymmetry of the areas and numbers of sunspots in the range of QBO periods display pronounced similarity. In the activity indices per se, these effects are much weaker: the mutual correlation of the indices is lower, the QBO are less pronounced, and the similarity of the SVAN diagrams in the QBO range is absent. The effect of negative correlation between the QBO power and absolute value of the asymmetry over a long time interval was revealed: the increase in asymmetry is accompanied by a decrease in QBO amplitude regardless of which hemisphere is more active at the moment. This underlines the global nature of QBO and the relation of asymmetry to the quadrupole component of the solar large-scale magnetic field. The asymmetry is an independent fundamental characteristic of solar activity, which does not reduce to the classical characteristics of the 11-year cycle. Title: `Active Longitudes' in the Heliomagnetic Reference Frame Authors: Obridko, V. N.; Chertoprud, V. E.; Ivanov, E. V. Bibcode: 2011SoPh..272...59O Altcode: 2011SoPh..tmp..322O; 2011SoPh..tmp..271O; 2011SoPh..tmp..202O; 2011SoPh..tmp..297O A new coordinate system - heliomagnetic reference frame - has been proposed in which the great circle passes through the solar pole and the north pole of the magnetic dipole is considered as the central meridian. It is shown that, in the new coordinate system, the active longitudes are defined much more clearly, are more stable in time, and are interlaced every 11 years. Title: Unexpected Solar Activity Cycle 24 Prediction by Various Methods Authors: Breus, T. K.; Ozheredov, V. A.; Obridko, V. N. Bibcode: 2011simi.confQ...1B Altcode: A considerable difference in maximum amplitude of the solar cycle (SC) 24 predicted by various methods exists according to conclusion of the Third Official Prediction Panel NOAA, NASA and International Environment Service (ISSE). Aim of our study is to update SC 24 forecast by comparative analysis of this problem using linear autoregressive approaches, nonlinear Neural - based method and method of precursor. As a predictor for construction of SC 24, we used an idea on dynamics of the solar magnetic fields forming solar spots, being basic for estimations of Wolf numbers Wn. For forecasting of variations of predictor – the solar polar field - in SC 24 the singular spectral analysis was used. Results: Our nonlinear Neural-based prediction gave value 70 for SC 24 amplitude in contrast with value 145 from official two predictions based on Neural network methods.

The proposed forecasting by precursor method based on solar polar field variations allows expanding a horizon of Wn prediction on one cycle. The SC 24 maximum is predicted by this method had to happen in April, 2012, and its average amplitude can be as low as 50 or even 20. The prolonged minimum of the Solar Cycle 23 and abnormal predicted values of Wn for the maximum of Solar Cycle 24 remind the scenario of transition of solar activity to the historical Dalton minimum. Title: Coronal Holes and High Speed Streams Authors: Obridko, V. N. Bibcode: 2011simi.conf....6O Altcode: We have analyzed the data on coronal holes observed in the Sun throughout the activity Cycle 23. It is shown that CH is not merely an undisturbed zone between the active regions. The reduced brightness is the result of a specific structure with the magnetic field being quasi-radial at as low altitude as 1.1R or a bit higher. The plasma outflow decreases the measure of emission from CH. With an adequate choice of the photometric boundaries, the CH area and brightness indices display a fairly high correlation (0.6-0.8) with the solar wind velocity throughout the cycle. The mean brightness of the darkest part of CH is of the order of 18-20% of the solar brightness, while the brightness of the other parts of the CH is 30-40%. It is shown that the parameters of the solar–wind magnetic field are determined at the level of 1.1–1.4 solar radii in the coronal hole, where the field lines are radial at low heights. Traditional comparison of the field parameters at the Earth orbit and at the Earth helioprojection point on the Sun is not quite correct. It is justified as far as the signs of the field and sector structure are concerned. However, the field absolute value is formed in a more extensive area. Taking this into account, we can correlate the field values in the Sun with the values of the IMF and explain the absence of weak fields in the vicinity of the IMF neutral line (two-peak distribution). Title: Longitude variations of solar magnetic fields of different intensity in cycle 23 as inferred from the SOHO/MDI data Authors: Obridko, V. N.; Chertoprud, V. E. Bibcode: 2011AstL...37..358O Altcode: 2011PAZh...37..392O SOHO/MDI magnetograms have been used to analyze the longitude distribution of the squared solar magnetic field < B 2> in the activity cycle no. 23. The energy of the magnetic field (< B 2>) is shown to change with longitude. However, these variations hardly fit the concept of active longitudes. In the epochs of high solar activity, one can readily see a relationship between longitude variations of the medium-strong ((| B| > 50 G or | B| > 100 G) and relatively weak (| B| ≤ 50 G or | B| ≤ 100 G) fields at all latitudes. In other periods, this relationship is revealed mainly at the latitudes not higher than 30°. The background fields (| B| ≤ 25 G) also display longitude variations, which are, however, not related to those of the strong fields. This makes us think that the fields of solar activity are rather inclusions to the general field than the source of the latter. Title: Relationship between the Parameters of Coronal Holes and High-Speed Solar Wind Streams over an Activity Cycle Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2011SoPh..270..297O Altcode: 2011SoPh..tmp...59O; 2011SoPh..tmp...82O The comparison of the brightness and area of coronal holes (CH) to the solar wind speed, which was started by Obridko et al. (Solar Phys.260, 191, 2009a) has been continued. While the previous work was dealing with a relatively short time interval 2000 - 2006, here we have analyzed the data on coronal holes observed in the Sun throughout activity Cycle 23. A catalog of equatorial coronal holes has been compiled, and their brightness and area variations during the cycle have been analyzed. It is shown that CH is not merely an undisturbed zone between the active regions. The corona heating mechanism in CH seems to be essentially the same as in the regions of higher activity. The reduced brightness is the result of a specific structure with the magnetic field being quasi-radial at as low an altitude as 1.1R or a bit higher. The plasma outflow decreases the measure of emission from CH. With an adequate choice of the photometric boundaries, the CH area and brightness indices display a fairly high correlation (0.6 - 0.8) with the solar wind velocity throughout the cycle, except for two years, which deviate dramatically - 2001 and 2007, i.e., the maximum and the minimum of the cycle. The mean brightness of the darkest part of CH, where the field lines are nearly radial at low altitudes, is of the order of 18 - 20% of the solar brightness, while the brightness of the other parts of the CH is 30 - 40%. The solar wind streams originate at the base of the coronal hole, which acts as an ejecting nozzle. The solar wind parameters in CH are determined at the level where the field lines are radial. Title: Solar Activity Cycle in Solar-wind Sources and Flows Authors: Lotova, N. A.; Vladimirskii, K. V.; Obridko, V. N. Bibcode: 2011SoPh..269..129L Altcode: 2010SoPh..tmp..243L Experiments based on multi-source radio occultation measurements of the circumsolar plasma at R∼4.0−70RS were carried out during 1997 - 2008 to locate the inner boundary of the solar-wind transonic transition region, Rin. The data obtained were used to correlate the solar-wind stream structure and magnetic fields on the source surface (R=2.5RS) in the solar corona. The method of the investigation is based on the analysis of the dependence Rin=F(|BR|) in the correlation diagrams, where Rin is the inner boundary of the solar-wind transition region and |BR| is the intensity of the magnetic field at the source surface. On such diagrams, the solar wind is resolved into discrete branches, streams of different types. The analysis of the stream types using a continuous series of data from 1997 to 2008 allowed us to propose a physical criterion for delimiting the epochs in the current activity cycle. Title: Open magnetic fields on the Sun and solar wind parameters at the Earth's orbit Authors: Obridko, V. N.; Shelting, B. D.; Livshits, I. M. Bibcode: 2011ARep...55..284O Altcode: 2011AZh....88..313O It is shown that the parameters of the solar-wind magnetic field are determined by regions in coronal holes at distances of 1.1-1.4 solar radii, where the field lines are radial at low heights. Expanding further in a narrow nozzle or funnel, the field lines become radial throughout the unipolar region at 2.5 solar radii. Hence, the traditional approach of comparing the characteristics of the interplanetary field at the Earth's orbit and at the corresponding helio-projection point on the Sun is not quite correct. It gives good results for the signs and sector structure of the field; however, the magnitude of the field is formed in a more extensive area. Taking this into account, we can correlate the field values on the Sun with the interplanetary magnetic field (IMF), and thus explain the absence of weak fields in the vicinity of the IMF neutral line (the two-peaked nature of the distribution). Title: On the nature of the in-ecliptic interplanetary magnetic field's two-humped distribution at 1AU Authors: Khabarova, Olga; Obridko, Vladimir Bibcode: 2011arXiv1102.1176K Altcode: It was found out that the distribution's shape of the in-ecliptic (as well as radial) component of the interplanetary magnetic field (IMF) significantly changes with the heliocentric distance, which poorly corresponds to classical models of the solar wind and the interplanetary magnetic field (IMF) expansion. For example, distributions of the radial photospheric and the source surface's magnetic field in the ecliptic plane are Gaussian-like, the distribution of the radial IMF component at the Earth orbit demonstrates two-humped shape, and it becomes again Gaussian-like at 3-4 AU. These differences lead to lack of correspondence between simulations of the IMF behaviour at 1 AU and observations. Our results indicate that picture of the IMF expansion into space is more complicated than usually considered, and the sector structure is not the only source of the two-humped shape of the in-ecliptic or radial IMF component. We have analysed data from different spacecraft at the distances from 0.29 AU to 4 AU and found that the shape of the radial IMF component distribution strongly depends on a heliocentric distance and a heliolatitude. The "two-humped IMF" effect is most brightly expressed at low heliolatitudes at 0.7-2 AU, but it fully disappears at 3-4 AU. There is also dependence of the IMF distributions' view on a solar cycle due to active processes, such as solar flares and CMEs. We suppose that the in-ecliptic solar wind field at 1 AU is influenced by solar active regions in a high degree, and actually the distribution is the three-humped: two humps correspond to the IMF from the middle and high heliolatitudes and the third one is the theoretically expected distribution from the solar field nearby the heliomagnetic equator. Vanishing of the IMF zero-component with the distance from the Sun partially could be a result of a magnetic reconnection at the current sheets in the solar wind. Title: Diagnostics of solar wind streams and their sources in the solar corona Authors: Lotova, N. A.; Vladimirskii, K. V.; Obridko, V. N. Bibcode: 2010Ge&Ae..50..711L Altcode: The studies are based on the experimental mass sounding of the interplanetary plasma near the Sun at radial distances of R = 4-70 R S, performed at Pushchino RAO, Russian Academy of Sciences, and on the calculated magnetic fields in the solar corona based on the magnetic field strength and structure measured on the Sun's surface at J. Wilcox Solar Observatory, United States. The experimental data make it possible to localize the position of the boundary closest to the Sun of the transition transonic region of the solar wind in the near-solar space ( R ≈ 10-20 R S) and to perform an interrelated study of the solar wind structure and its sources, namely, the magnetic field components in the solar corona based on these data. An analysis of the evolution of the flow types in 2000-2007 makes it possible to formulate the physically justified criterion responsible for the time boundaries of different epochs in the solar activity cycle. Title: Correction of Observations When Calculating Heliospheric Magnetic Fields from Solar Magnetograph Data Authors: Obridko, V. N.; Asgarov, A. B.; Shelting, B. D.; Babayev, E. S. Bibcode: 2010SunGe...5...34O Altcode: The nature of the discovered difference between the histograms of distribution of the daily mean magnetic fields in the heliosphere near the Earth and on the source surface in the Sun is discussed. The magnetic field measured near the Earth is a bit smaller than the calculated one and has a two-peak distribution. We propose a new correction method, which takes into account the saturation of magnetographs and the contribution of high-latitude fields. The calculations carried out by this method display better agreement with observations; however a detailed distribution of fields inside the sector can not be described by a simple classical model. Title: Long-term modulation of galactic cosmic rays at solar activity minimums Authors: Gushchina, R. T.; Belov, A. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2010Ge&Ae..50..436G Altcode: Based on observations of long-term variations in galactic cosmic rays (CRs) on Earth and in the near-Earth space, we have determined, using our own semiempirical model, modulation of galactic CRs during solar cycles 19-23. The modulation model relates CR variations to the characteristics of the solar magnetic field obtained for the surface of the solar wind source at distances of 2.50 and 3.25 solar radii. The main focus is CR behavior at the minimums of cycles 19-23 and specific features of CR modulation at a prolonged (as compared to previous cycles) minimum of cycle 23, which is still ongoing. CR modulation at minimums related to a change in the solar field dipole component during this period of the cycle has been considered. It is indicated that the long-term variations in CRs are better described if the last two years (2007 and 2008) of cycle 23 with anomalously low solar activity (SA) are included in the model. The role and value of the contribution of the cyclic variations in each index used in the proposed CR modulation model to the observed CR modulation have been estimated. Title: Large-scale patterns and ‘active longitudes’ Authors: Obridko, Vladimir N. Bibcode: 2010IAUS..264..241O Altcode: The following aspects of the physics of large-scale solar magnetic fields are discussed: structure of large-scale fields (LSF) and connection with local fields; dynamo and origin of LSF; LSF cycle variation; meridional circulation and LSF; rotation of LSF; fine structure of the field in quiet regions and the concept of the pebble-shaped field; active longitudes, their manifestation in various solar indices, and dependence on the power of solar activity. Title: Magnetic reconnection as a possible cause of in-ecliptic IMF zero vanish on the way from the Sun to the Earth Authors: Khabarova, Olga; Obridko, Vladimir Bibcode: 2010cosp...38.1932K Altcode: 2010cosp.meet.1932K If we look at the distributions of Bx and By -horizontal components of interplanetary magnetic field (IMF) at the Earth orbit, we can see striking hole in the area near zero. There are two peaks of By and Bx distributions: one negative and one positive, while the Bz component is distributed around zero. For many years this fact has been simply explained by geometrical considerations. It has been supposed that sector structure of IMF leads to observation of predominant negative or positive horizontal IMF component sign, first of all, because heliospheric current sheet (where zero magnetic line always exists) is enough thin and it passes the Earth very fast in comparison with the positive or negative sector stay time. The next explanation was the high inclination of the heliospheric current sheet, which is often concidered to be perpendicular to the ecliptic plane. These explanations seemed so obvious that the problem even had not been discussed in the literature so long as V.Obridko in 2006 pointed out at the fact of significant mismatching of horizontal IMF components distribution near the Earth and distribution of magnetic field at the Sun (for the projection of the Earth to the solar wind source surface). Solar magnetometers allow measure radial component of magnetic field at the Sun with the accuracy and time resolution enough for comparison with near-Earth IMF spacecraft data. The radial solar magnetic field in the interplanetary space should decrease as r-2 for a quiet flowing out stream. Modern successful calculations of in-ecliptic IMF at the Earth orbit are mainly based on this law, but calculated horizontal field values are permanently lower than measured ones. Moreover, distribution of radial solar magnetic field is fundamentally different from spacecraft measured in-ecliptic magnetic field distribution: there is no double-humped distribution of field at the Sun; it is usual Gauss-like one. It was shown these variances can not be explained by "technical" causes, and it is necessary to seek for physical nature of these differences. There are evidences that near-Earth "zero" is lost even at the heliospheric current sheet. Shortfall of IMF zero values could be explained by unceasing magnetic reconnection at the heliospheric current sheet (sector boundary) as well as at current sheets often associating with the streamer belt. As a result the main zero-line gets thinner and thinner on the way from Sun to the Earth, and the heliosheric current sheet becomes wider, looks like a sandwich, full of reconnection's products. Simulation results and experimental proofs of reconnection at the heliospheric current sheets and at small-scale current sheets in space plasma are given. Title: Influence of space weather on human organism at different geo-latitudes: telecommunication helio-medical monitoring "Geliomed" 2003-2010 Authors: Ragulskaya, Maria; Obridko, Vladimir; Samsonov, Sergey; Vitaliy, Vishnevskey; Grigoryev, Pavel; Valeriy, Pipin; Khabarova, Olga Bibcode: 2010cosp...38.3401R Altcode: 2010cosp.meet.3401R We discuss the results of the long-term telecommunicative biogeophysical monitoring "Geliomed" (2003-2010). The purpose is to explore the effects of spatial and temporal variations in space weather and climatic factors on the human health state. The monitoring is carried out simultaneously at the different geographical areas that covers the different latitudes. The project developed in the joint collaboration the Ukrainian National Academy of Science and the Russian Academy of Science. The experiment carried out simultaneously in Moscow, Yakutsk, Kiev and Simferopol. The principal components of the experiment can be summarized as follows: 1. Equipments and data gathering methods are the same for all the scientific cen-ters which are involved in experiment. Research centers working with the same equipment and using the same protocols with on-line registration of current data on same portal server (http//geliomed.immsp.kiev.ua) 2. The groups of patients involved in the program are kept the same for the whole observational period of time. 3. The daily registered parameters in-clude: psycho-emotional tests and 1-st lead ECG (contain 25 000 measurements for the whole period), arterial pressure (100 000 measurements), variability cardiac contraction (25000 mea-surements), electric conduction of bioactive points on skin (more than 500 000 measurements for the whole period ). 4. The every patient in the monitoring group is examined at the 4 functional states. Registration is done at rest, after standard psychology test, Roufiet test, and after 10 min relax. 5. The data of the ECG measurements are analyzed in the phase space constructed from the signal and its derivative. 6. The results time series were compared with daily values of space weather and geomagnetic parameters. Results. In the all monitoring centers all the patients involved in the monitoring show the same type of changes in the cardiac activity parameters during an isolated magnetic storm. Such a change of the ECG parameters occurs nearly simultaneously for all the centers. The higher latitude, the greater amplitude of the ECG parameters change. The properties of the detected phenomena can be summarized as follows: -The dynamics of adaptation programs changes during the storm. The maximum amplitude of change is observed for the healthy patients. -The number of none-typical ECG beats increase; -There are no clear evidences for variations of RR intervals during geomagnetic storms. -Man are more sensitive to magnetic storms, while endogenous rhythms predominate for females; Additionally, we find, that the embedding of ECG time series in 3D phase space can be considered as a mix of a few states. At the rest, the occurrence of the basic ECG state compare to additional ones is about 8:2. The occurrence of the basic state increases after the stress. Thus, the external stress may change the relative disorder of the system. To understand the origin of the standard cardio-cycle changes we reconstruct of the dynamical model of the individual cardiac beat. The reconstruction reveals that the typical evolution of the cardiac rhythm includes the drift of attractor in the embedding space and the sudden change between a few basic patterns of attractor. However one of pattern is always dominating. These several pattern of ECG beat attractor can be ascribed to a several states of the system. Qualitatively, the nonlinear ECG dynamics is defined by the stationary points, which are inside into Q and T waves. Conclusions: many-year telecommunication heliomedical monitoring in different lat-itudes showed, that space and geophysical factor act as a training factor for the adaptation-resistant member of the population. It serve as a channel for rejection of nonviable members of the population, synchronize the total populations rhythms, create conditions for generation of new information in the process of evolution adaptation of biological systems in general. Title: Possible Effects of Solar and Geomagnetic Activity on Sudden Cardiac Death in Middle Latitudes Authors: Dimitrova, S.; Babayev, E. S.; Georgieva, K.; Obridko, V. N.; Mustafa, F. R. Bibcode: 2009SunGe...4...84D Altcode: In this paper results revealing potential effects of solar activity (SA) and geomagnetic activity (GMA) on the dynamics of sudden cardiac death (SCD) in middle latitudes are described. Medical data were taken from all of emergency and first medical aid stations of Grand Baku Area with millions of inhabitants for the time period 2003-2005. In total 788 SCD cases were analyzed. ANalysis Of VAriance (ANOVA) was applied to study the significance of GMA influence, estimated by different geomagnetic indices, and the type of geomagnetic storms (caused by the solar origin magnetic clouds (MC) and by high speed solar wind streams (HSSWS)) on SCD. Correlation analysis was carried out and relevant coefficients were calculated. Obtained results revealed strong negative correlation between monthly averaged GMA and SCD in Baku for the considered period. ANOVA revealed that SCD number was largest on the days of low GMA, on the days of highest geomagnetic field variations and even on +2nd day after them. It was established that SCDs increased on the days of storms caused by HSSWS and remained higher till +2nd day after they finished. Title: Contrast of Coronal Holes and Parameters of Associated Solar Wind Streams Authors: Obridko, V. N.; Shelting, B. D.; Livshits, I. M.; Asgarov, A. B. Bibcode: 2009SoPh..260..191O Altcode: It is shown that the contrast of coronal holes, just as their size, determines the velocity of the solar wind streams. Fully calibrated EIT images of the Sun have been used. About 450 measurements in 284 Å have been analyzed. The time interval under examination covers about 1500 days in the declining phase of cycle 23. All coronal holes recorded for this interval in the absence of coronal mass ejections (CMEs) have been studied. The comparison with some other parameters (e.g. density, temperature, magnetic field) was carried out. The correlations with the velocity are rather high (0.70 - 0.89), especially during the periods of moderate activity, and could be used for everyday forecast. The contrast of coronal holes is rather small. Title: Relationship between the contrast of coronal holes and parameters of the solar wind streams Authors: Obridko, V. N.; Shelting, B. D.; Livshits, I. M.; Askerov, A. B. Bibcode: 2009ARep...53.1050O Altcode: 2009AZh....86.1125O It is shown that the contrast of coronal holes (CH) determines the speed of the solar wind streams to the same extent as their area does. We analyzed more than 400 images obtained in the λ284 Å channel. The time interval under examination covers about 1500 days in the declining phase of cycle 23 (from 2002 to 2006). We considered all coronal holes recorded during that interval in the absence of coronal mass ejections (CME). Comparison was also made with some other parameters of the solar wind (e.g., density, temperature, and magnetic field). A fairly high correlation (0.70-0.89) was obtained with the velocity, especially during the periods of moderate activity, which makes this method useful for everyday forecast. The ratio of CH brightness to the mean brightness of the disk in the λ284 Å channel is about 25%. Title: Fine-scale Stochastic Structure of Solar Magnetic Fields Authors: Chertoprud, V.; Ioshpa, B.; Obridko, V. Bibcode: 2009ASPC..405..205C Altcode: Fine-structure (∼10'') stochastic properties of the magnetic field of the Sun have been analyzed in the frames of a two-dimensional model of the fractal Brownian process (mean square of the field magnitude difference at two points spaced by a distance D is proportional to D2H). The standard deviation s of the magnetic field and the exponent H corresponding to different levels of mid Bmid have been determined using digitized solar magnetograms with 2'' resolution \citep[SOHO/MDI,][]{chertoprud_Scherrer_1995}. It is established that transition from the background magnetic field to the active region (AR) magnetic fields occurs in the field region 25-50 G. The exponent H has been determined as a function of the magnetic field magnitude. The exponent H for the background magnetic field is essentially smaller than for the AR fields. The relation between the results obtained and some fundamental properties of the behavior of solar plasma (turbulence, convection) are discussed. Title: Small-scale background magnetic field on the sun in solar cycle 23 Authors: Ioshpa, B. A.; Obridko, V. N.; Chertoprud, V. E. Bibcode: 2009AstL...35..424I Altcode: 2009PAZh...35..472S Based on SOHO/MDI data (an archive of magnetic maps with a resolution of ∼2″), we have investigated the dynamics of the small-scale background magnetic field on the Sun in solar cycle 23. The cyclic variations and surface structure of the background magnetic field have been analyzed using the mean estimates of < B> and < B 2> of the observed magnetic field strength B for various solar surface areas and at various B levels. We have established that the cyclic variations of <2> at latitudes below 30° are essentially similar to those of the total radio flux F 10.7. A significant difference between the background magnetic fields in the northern and southern solar hemispheres persisting throughout the solar cycle has been detected. We have found the effect of background magnetic field growth toward the solar limb and concluded that the transversal component in the background magnetic field is significant. The relatively weak small-scale background magnetic fields are shown to form a special population with its own special laws of cyclic variation. Title: About the role of the Sun magnetic field characteristics in the long-term galactic cosmic rays modulation Authors: Gushchina, R. T.; Belov, A. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2009BRASP..73..334G Altcode: No abstract at ADS Title: Anomalies in the evolution of global and large-scale solar magnetic fields as the precursors of several upcoming low solar cycles Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2009AstL...35..247O Altcode: 2009PAZh...35..279O Anomalies in the solar magnetic fields of various scales are studied. The polar magnetic field strength is shown to have decreased steadily during the last three solar cycles. This is because the increase in the dipole magnetic moment observed from 1915 to 1976 has changed into a decrease in the last three cycles. At the same time, the medium scale magnetic fields (like those of isolated coronal holes) have been unusually strong in the last cycle. As a result, the tilt of the heliospheric current sheet is still about 30°. The large effective contribution from the medium scale fields to the total energy of the large-scale fields is also confirmed by our calculations of the effective multipolarity index. The aa-index at the cycle minima is correlated with the height of the succeeding maxima. The set of data considered may be indicative of the possible approach of a sequence of low solar cycles. Title: The role of cyclic solar magnetic field variations in the long-term cosmic ray modulation Authors: Gushchina, R. T.; Belov, A. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2009AdSpR..43..673G Altcode: Updating the semi-empirical model of cosmic rays (CR) modulation proposed in our previous work has been discussed. In order to provide a description of long-term variations, in which the CR modulation would adequately reflect the complex interaction of global and local solar magnetic fields, we have supplemented the model with the following characteristics: the solar magnetic field polarity, the integral index, the partial indices, the tilt of the current sheet, and the index characterizing the X-ray flares. The role of each index in the CR modulation has been determined. In the multi-parameter description of long-term CR variations using the integral index or one of four partial indices, the best fit for the period 1977-1999 has been obtained for the integral index and the sector-odd index characterizing the inclined dipole. The discrepancy between the model and observations increases from the beginning of 2000. Therefore, the problematic features in the behavior and modeling of CR during cycle 23 have been discussed. It is suggested that the cycle-to-cycle decrease of the CR density in the minimum epochs of the past solar activity (SA) cycles could be explained by the decrease of the zone-odd index. Title: The reflection in the long-term cosmic rays modulation of the cyclic variations of integral and partial indices of the solar magnetic field Authors: Gushehina, R. T.; Belov, A. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2009ecrs.conf..226G Altcode: No abstract at ADS Title: Manifestations of cyclic variations in the solar magnetic field in long-term modulation of cosmic rays Authors: Gushchina, R. T.; Belov, A. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2008Ge&Ae..48..571G Altcode: The possibilities of improving the semiempirical model of cosmic ray (CR) modulation, proposed by us previously, are discussed. The following characteristics have been considered as model parameters in order to describe long-period CR variations using a unified model and to more completely reflect solar cycles in CR modulation as a complex interaction between two systems of fields (large-scale and local): the value and sign of the polar solar field, the average strength of the solar magnetic field (the B ss integral index), partial indices (zone-even ( ZE) and zone-odd ( ZO) and sector-even ( SE) and sector-odd ( SO) indices), the tilt of the heliospheric current sheet, and the special index ( F x ) taking into account X ray flares. The role of each index in CR modulation has been revealed. When we described the long-term CR variations using many parameters and taking into account the integral index or one of four partial indices, the best results of modulation modeling during 1976 1999 were obtained for the B ss total energetic index and SO index. A difference between the model calculations and observations increases beginning from the middle of 2000; the problem features of the CR behavior and the specific features of modeling this behavior in cycle 23 of solar activity (SA) are discussed. It is assumed that a decrease in the CR density at the last SA minimums (from cycle to cycle) can be related to a decrease in the ZO index and to a recently detected similar decrease in the vertical component of the solar dipole magnetic moment. Title: Predictions of the Magnitude of the Forthcoming Solar Cycles using Knowledge on the Solar Dynamo and Singular Spectrum Analysis Authors: Kuzanyan, K.; Obridko, V. N.; Kotlyarov, O. L.; Loskutov, A. Y.; Istomin, I. A. Bibcode: 2008ESPM...12.2.69K Altcode: We present results of a series of studies on revealing regularities and predictions of the magnitude and duration of the solar cycle by simultaneous use of the knowledge on the Solar Dynamo mechanism and the arsenal of time series methods, such as Singular Spectrum Analysis (SSA).

The key properties of the solar dynamo have been obtained by consideration of the nonlinear Parker dynamo waves in a thin shell, which enables links between amplitude and phase of the solar magnetic activity. Further, the sunspot index series have been analysed using time series methods, and predictions on the magnitude of this activity has been produced.

On the basis of these computations we expect the two forthcoming solar cycles to be a bit lower than the previous ones, namely the maximum 12-month averaged Wolf number for the cycle 24 is expected in the second half of 2011 as approximately 106, and for cycle 25 in 2021 about 99, given the uncertainties.

Furthermore, the theory of nonlinear dynamo waves establishes a link between the growth rate of the solar activity in the phase of rise of the cycle with its maximum value, supported by observational regularities. We are going to refine our predictions of this cycle 24 maximum magnitude shortly, once the stable cycle growth is indicated. Title: Temporal variations in the position of the heliospheric equator Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2008ARep...52..676O Altcode: 2008AZh....85..750O It is shown that the centroid of the heliospheric equator undergoes quasi-periodic oscillations. During the minimum of the 11-year cycle, the centroid shifts southwards (the so-called bashful-ballerina effect). The direction of the shift reverses during the solar maximum. The solar quadrupole is responsible for this effect. The shift is compared with the tilt of the heliospheric current sheet. Title: Diagnostics of solar wind flows Authors: Lotova, N. A.; Vladimirskii, K. V.; Obridko, V. N. Bibcode: 2008AstL...34..500L Altcode: 2008PAZh...34..551L The formation of the solar wind, the plasma flows from the Sun, is studied by new methods that have been developed in recent years. Experiments on circumsolar plasma sounding at radial heliocentric distances of ∼2.5 60 R form their basis. Experimental data are used to construct the correlation diagrams-the location of the boundary of the transonic solar wind transition region versus the magnetic field strength in the region of the flow sources. The 2000 2004 correlation diagrams reveal flows of six types that differ by the magnetic field structure in their sources. During the decline of solar activity in 2003 2004, the evolution of the slow solar wind flows has been found to be determined not by the Wolf numbers, but by the total strength of the global magnetic field in the solar corona. Title: On Prediction of the Strength of the 11-Year Solar Cycle No. 24 Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2008SoPh..248..191O Altcode: 2008SoPh..tmp...38O Various forecast techniques have been analyzed with reference to solar activity cycle 24. Three prediction indices have been proposed: the intensity of the polar field, the mean field at the source surface, and a recurrence index of geomagnetic disturbances. As a rule, the forecast based on the polar field and extrapolation of local fields gives a height for cycle 24 that is smaller than that of cycle 23. The use of the recurrence index and the global field value leads us to the conclusion that cycle 24 will be medium high: the same as or somewhat higher than cycle 23. Title: Fractal properties of solar magnetic fields Authors: Ioshpa, B. A.; Obridko, V. N.; Rudenchik, E. A. Bibcode: 2008AstL...34..210I Altcode: 2008PAZh...34..234I We study the spatial properties of solar magnetic fields using data from the Solar Vector Magnetograph of the Marshall Space Flight Center (MSFC) (FeI 5250.2 Å) and SOHO/MDI longitudinal magnetic field measurements (Ni 6767.8 Å) (96-min full-disk maps). Our study is focused on two objects: the fractal properties of sunspots and the fractal properties of the spatial magnetic field distribution of active and quiet regions considered as global structures. To study the spatial structure of sunspots, we use a well-known method of determining the fractal dimension based on an analysis of the perimeter—area relation. To analyze the fractal properties of the spatial magnetic field distribution over the solar surface, we use a technique developed by Higuchi. We have revealed the existence of three families of self-similar contours corresponding to the sunspot umbra, penumbra, and adjacent photosphere. The fractal coefficient has maxima near the umbra—penumbra and penumbra—photosphere boundaries. The fractal dependences of the longitudinal and transverse magnetic field distributions are similar, but the fractal numbers themselves for the transverse fields are larger than those for the longitudinal fields approximately by a factor of 1.5. The fractal numbers decrease with increasing mean magnetic field strength, implying that the magnetic field distribution is more regular in active regions. Title: Current Helicity and Twist as Two Indicators of the Mirror Asymmetry of Solar Magnetic Fields Authors: Sokoloff, D.; Zhang, H.; Kuzanyan, K. M.; Obridko, V. N.; Tomin, D. N.; Tutubalin, V. N. Bibcode: 2008SoPh..248...17S Altcode: 2008arXiv0802.3668S; 2008SoPh..tmp...19S A comparison between the two tracers of magnetic field mirror asymmetry in solar active regions - twist and current helicity - is presented. It is shown that for individual active regions these tracers do not possess visible similarity but averaging by time over the solar cycle, or by latitude, reveals similarities in their behavior. The main property of the data set is antisymmetry over the solar equator. Considering the evolution of helical properties over the solar cycle we find signatures of a possible sign change at the beginning of the cycle, though more systematic observational data are required for a definite confirmation. We discuss the role of both tracers in the context of solar dynamo theory. Title: Quasi-Biennial Oscillations in the North - South Asymmetry of Solar Activity Authors: Badalyan, O. G.; Obridko, V. N.; Sýkora, J. Bibcode: 2008SoPh..247..379B Altcode: 2008SoPh..tmp...13B The north - south (N - S) asymmetry of solar activity is investigated by using the data on coronal green-line brightness and total number and total area of sunspots over the period of 1939 - 2001. Typical time variations of the N - S asymmetry are found to be consonant in these indices. Quasi-biennial oscillations (QBO) of solar activity are well recognizable in the N - S asymmetry of the examined indices. Moreover, the QBO are much better manifested in the N - S asymmetry of the individual indices than in the original (N plus S) indices. The time variations of relative QBO power are synchronous for the N - S asymmetry of various solar activity indices whereas such a synchronization is weaker for the indices themselves. It is revealed that the relative QBO power found in the N - S asymmetry of the studied indices has a negative correlation with the value of the N - S asymmetry itself. The findings indicate that the N - S asymmetry should be regarded as a fundamental phenomenon of solar activity similarly manifested in different activity indices. These findings should be taken into account when any dynamo theory of solar activity is constructed. Title: Manifestation of the solar global field changes in the long-term cosmic rays modulation Authors: Gushchina, R. T.; Belov, A. V.; Obridko, V. N.; Shelting, B. D.; Balabin, Yu. V. Bibcode: 2008ICRC....1..473G Altcode: 2008ICRC...30a.473G We discuss the improving of the semi-empirical model of cosmic ray (CR) modulation proposed by us previously. In order to describe the long-term variations with more complete reflection in the CR modulation of the complex interaction of global and local solar magnetic fields it has been proposed to introduce into the model the next characteristics: the solar magnetic field polarity, the integral index iBr, the partial indexes as well the tilt of the current sheet and the flare index. The role of each index in the CR modulation is determined. For the multi-parameter description of long-term CR variations by using the integral index or one of four partial indexes the best fit for 1977-1999 period is obtained for the index iBr and the sector-odd index, characterising an inclined dipole. It is proposed that decreasing of density CR in minima of the last SA cycles (from cycle to cycle) could be explained by decreasing of the zone-odd index and similar decreasing of the vertical component of the total magnetic moment. The discrepancy between the model and observations increases beginning from the middle of 2000 therefore the problematic features of CR behavior and modeling during the 23rd cycle are discussed. Title: Small-scale stochastic structure of the solar magnetic field Authors: Ioshpa, B. A.; Obridko, V. N.; Chertoprud, V. E. Bibcode: 2007AstL...33..844I Altcode: 2007PAZh...33..941I The small-scale (∼10″) stochastic properties of the solar magnetic field B are analyzed in terms of the two-dimensional model of a fractal Brownian process (the mean square of the difference between the field strengths at two points separated by a distance D is proportional to D 2 H ). Digitized solar magnetograms with a 2″ resolution are used to determine the standard deviation s of the magnetic field and the exponents H at various levels of | B|. It has been established that the transition from the background magnetic field to the fields of an active region occurs near 25 50 G. A dependence of the exponent H on the magnetic field amplitude has been derived. The exponent H for the background magnetic field has been found to be much smaller than that for the fields of an active region. The relationship of the results obtained to certain fundamental properties of plasma in a magnetic field is discussed. Title: Diagnostics of solar wind streams Authors: Lotova, N. A.; Vladimirskii, K. V.; Obridko, V. N. Bibcode: 2007A&AT...26..501L Altcode: No abstract at ADS Title: Asymmetry in the Inward-Outward Polarity in the Interplanetary Magnetic Field Authors: Asgarov, A. B.; Obridko, V. N. Bibcode: 2007SunGe...2...29A Altcode: Distribution of the magnetic field of solar wind near the Earth was investigated and compared with one expected from the classical model. It is shown that the presence of two peaks in the distribution of interplanetary magnetic field values, founded by Belov, Obridko and Shelting (2006), is not an artefact of averaging but reflects the real structure of magnetic field inside a sector. Moreover, the magnetic field of the polarity corresponding to the leading sunspot of the Northern Hemisphere is observed more frequently. With solar activity rise the growth of both the module of a magnetic field and the fields of each polarity separately were determined. The distance between peaks increases from 6 nT to 10 nT. In alternate amplification of peaks a quasi-22-year cycle was observed while in the intensity of a field of each polarity there was revealed a 11-year cycle, and in ratio of peaks to frequency of occurrence of zero values - a quasi-2-year (2.6±0.3 year) cycle. Approximately in 25 % of all cases the classical model is violated. Title: Magnetic cloud in the solar wind: A comparison with the classical model Authors: Askerov, A. B.; Obridko, V. N. Bibcode: 2007Ge&Ae..47..285A Altcode: The solar wind magnetic field distribution near the Earth has been studied and compared with the distribution anticipated according to the classical model. It has been indicated that a two-hump distribution of the IMF values discovered previously is not an artifact of averaging but reflects the actual structure of the magnetic field within the sector. In this case the magnetic field of polarity corresponding to the leading spot in the Northern Hemisphere is encountered more frequently. Not only the magnetic field magnitude but also the fields of either polarity increase with increasing activity. The distance between the peaks on the histogram of the magnetic field near the Earth increases from 6 to 10 nT. The quasi-22-year, 11-year, and quasibiennial (2.6 ± 0.3 years) cycles are observed in an alternate increase in the peaks, in the strength of the fields of either polarity, and in the ratio of the peaks to the occurrence frequency of zero values, respectively. The classical model is violated in approximately 25% of cases. Title: Some Structural Properties of Solar Magnetic Fields Authors: Ioshpa, B.; Mogilevskii, E.; Obridko, V. Bibcode: 2007ASPC..368..245I Altcode: We discuss some results of the study of spatial characteristics of solar magnetic fields. The analysis is based on the magnetic field data obtained with a new spectromagnetograph installed on the IZMIRAN Tower Telescope (Fe I 6302.5 Å) (Kozhevatov et al., 2002), the data of the MSFC solar vector magnetograph (Fe I 5250.2 Å) and the data of longitudinal magnetic 96 m daily maps of SOHO/MDI magnetograph (Ni I 6768 Å) downloaded through Internet. Our study was directed in some different ways: the fractal properties of sunspots; fractal properties of space distribution of the magnetic fields along great distances comparable with the size of active regions or active complexes; fractal properties of active and quiet regions as global entities. To do it we used some different methods, particularly, the well known method using the relation between the area and the perimeter of magnetic field lines (see (Feder, 1988; Meunier, 1999; Nesme-Ribes at al., 1996; Balke et al., 1993)) and technique developed by Higuchi (1988), who applied it to the investigation of long time series. Note also that magnetic structure in terms of the fractal models was developed earlier in (Zelenyi & Milovanov, 1991; Milovanov & Zelenyi, 1993; Mogilevskii, 1994; Mogilevskii, 2001; Abramenko et al., 2002; Abramenko, 2005; Salakhudinova & Golovko, 2005).

The main results are:

1. Fractal analysis of sunspot magnetic field indicated the existence of three families of self-similar contour lines roughly belonging to the umbra, penumbra and the ambient photosphere correspondingly. The greatest fractal dimension corresponds to the regions of weakest fields (ambient photosphere), the least one corresponds to the intermediate region (penumbra).

2. More detailed analysis shows that the fractal coefficient has a maximum (about 1.50) near the umbra--penumbra interface.

3. The global fractal numbers of space distribution of magnetic field on solar surface is closely connected with the mean absolute values of the longitudinal magnetic field for this surface. The fractal numbers diminish with the rising of mean magnetic field (from values about 2.0 for the relatively quiet region to 1- 1.2 for very active regions).

4. The dependences of fractal numbers of the space distribution of longitudinal and transversal fields versus mean longitudinal field are similar by their character but the fractal values for transversal field are higher than the corresponding factor values for longitudinal field by factor about 1.5. This means that the distribution of transversal field along the space is more chaotic than the distribution of longitudinal field. Title: A generalized polarity rule for solar magnetic fields Authors: Obridko, V. N.; Shel'Ting, B. D. Bibcode: 2007ARep...51..339O Altcode: 2007AZh....84..380O No abstract at ADS Title: To the problem of solar coronal heating Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 2007AstL...33..182B Altcode: 2007PAZh...33..210B We consider the adequacy of various solar coronal heating models. We show that the correlation between the intensity of the coronal Fe XIV 530.5 nm green line and the calculated magnetic field strength in the solar corona can be a useful tool for this purpose. We have established this correlation for coronal structures and magnetic fields of large spatial and temporal scales. The correlation found exhibits a strong dependence on both solar cycle phase and heliolatitude. The efficiency of a particular coronal heating mechanism is probably determined by the relative area occupied by low and high loops (including open structures). The direct current models based on slow field dissipation (DC) and the wave models based on Alfvén and magnetosonic wave dissipation (AC) are more efficient in the equatorial and polar zones, respectively. Title: Occurrence of the 1.3-year periodicity in the large-scale solar magnetic field for 8 solar cycles Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2007AdSpR..40.1006O Altcode: The data on solar magnetic fields since 1915 have been inferred from H-alpha filament observations. We have used these data together with direct magnetographic observations to study the cycle variation of the large-scale field. Quasi-periodic oscillations with a period of 1.3 years have been detected in the Sun during 8 cycles. They are not present all the time, but are rather seen at maxima and in declining phases of some cycles. No distinct correlation is revealed with the height of the cycle and alternation of the even and odd cycles. Oscillations with a period of 1.3 years are closely associated with quasi-biennial oscillations (QBO) but, occasionally, they occur in anti-phase. Title: Two Regularities in the Coronal Green-Line Brightness Magnetic Field Coupling and the Heating of the Corona Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 2006SoPh..238..271B Altcode: 2006SoPh..tmp...54B To study the quantitative relationship between the brightness of the coronal green line 530.5 nm Fe XIV and the strength of the magnetic field in the corona, we have calculated the cross-correlation of the corresponding synoptic maps for the period 1977 - 2001. The maps of distribution of the green-line brightness I were plotted using every-day monitoring data. The maps of the magnetic field strength B and the tangential Bt and radial Br field components at the distance 1.1 R were calculated under potential approximation from the Wilcox Solar Observatory (WSO) photospheric data. It is shown that the correlation I with the field and its components calculated separately for the sunspot formation zone ±30° and the zone 40 - 70° has a cyclic character, the corresponding correlation coefficients in these zones changing in anti-phase. In the sunspot formation zone, all three coefficients are positive and have the greatest values near the cycle minimum decreasing significantly by the maximum. Above 40°, the coefficients are alternating in sign and reach the greatest positive values at the maximum and the greatest negative values, at the minimum of the cycle. It is inferred that the green-line emission in the zone ±30° is mainly controlled by Bt, probably due to the existence of low arch systems. In the high-latitude zone, particularly at the minimum of the cycle, an essential influence is exerted by Br, which may be a manifestation of the dominant role of large-scale magnetic fields. Near the activity minimum, when the magnetic field organization is relatively simple, the relation between I and B for the two latitudinal zones under consideration can be represented as a power-law function of the type I ∝ Bq. In the sunspot formation zone, the power index q is positive and varies from 0.75 to 1.00. In the zone 40 - 70°, it is negative and varies from −0.6 to −0.8. It is found that there is a short time interval approximately at the middle of the ascending branch of the cycle, when the relationship between I and B vanishes. The results obtained are considered in relation to various mechanisms of the corona heating. Title: Variations of the dipole magnetic moment of the sun during the solar activity cycle Authors: Livshits, I. M.; Obridko, V. N. Bibcode: 2006ARep...50..926L Altcode: No abstract at ADS Title: International Colloquium "Scattering and Scintillation in Radio Astronomy" was held on June 19-23, 2006 in Pushchino, Moscow region, Russia Authors: Shishov, V. I.; Coles, W. A.; Rickett, B. J.; Bird, M. K.; Efimov, A. I.; Samoznaev, L. N.; Rudash, V. K.; Chashei, I. V.; Plettemeier, D.; Spangler, S. R.; Tokarev, Yu.; Belov, Yu.; Boiko, G.; Komrakov, G.; Chau, J.; Harmon, J.; Sulzer, M.; Kojima, M.; Tokumaru, M.; Fujiki, K.; Janardhan, P.; Jackson, B. V.; Hick, P. P.; Buffington, A.; Olyak, M. R.; Fallows, R. A.; Nechaeva, M. B.; Gavrilenko, V. G.; Gorshenkov, Yu. N.; Alimov, V. A.; Molotov, I. E.; Pushkarev, A. B.; Shanks, R.; Tuccari, G.; Lotova, N. A.; Vladimirski, K. V.; Obridko, V. N.; Gubenko, V. N.; Andreev, V. E.; Stinebring, D.; Gwinn, C.; Lovell, J. E. J.; Jauncey, D. L.; Senkbeil, C.; Shabala, S.; Bignall, H. E.; Macquart, J. -P.; Rickett, B. J.; Kedziora-Chudczer, L.; Smirnova, T. V.; Rickett, B. J.; Malofeev, V. M.; Malov, O. I.; Tyulbashev, S. A.; Jessner, A.; Sieber, W.; Wielebinski, R. Bibcode: 2006astro.ph..9517S Altcode: Topics of the Colloquium: a) Interplanetary scintillation b) Interstellar scintillation c) Modeling and physical origin of the interplanetary and the interstellar plasma turbulence d) Scintillation as a tool for investigation of radio sources e) Seeing through interplanetary and interstellar turbulent media Ppt-presentations are available on the Web-site: http://www.prao.ru/conf/Colloquium/main.html Title: Variation of the Dipole Magnetic Moment of the Sun during an Activity Cycle Authors: Livshits, I. M.; Obridko, V. N. Bibcode: 2006IAUJD...8E...6L Altcode: Observations of large-scale solar magnetic fields (synoptic charts) and the Sun as a star (general magnetic field) have been used to determine the magnetic moment and direction of the dipole field for the past three solar cycles. Both the magnitude of the magnetic moment and its vertical and horizontal components proved to change regularly in the course of a solar cycle never vanishing completely. A wavelet analysis has shown that the amplitude of 27-day variations of the general magnetic field of the Sun (GMF) is closely related to the magnitude of the horizontal dipole. The sign reversal of the global dipole consists in the change of inclination angle of its axis. The reversal process is not smooth but occurs in steps lasting for 1-2 years. Before the reversal, the dipole axis is precessing with respect to the solar rotation axis. Then, it moves in the meridional plane to reach very low latitudes, where it begins to shift significantly in longitude. These results are discussed in the context of helioseismic inferences of the existence of oscillations with a period of about 1.3 years and particularities of the dynamo processes in the case of inclined rotator. Title: To the Problem of the Corona Heating Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 2006IAUJD...3E..10B Altcode: The adequacy of different models of the corona heating is discussed. The correlation between the brightness of the coronal green line 530.5 nm Fe XIV and the calculated strength of the magnetic field in the corona is shown to be a very useful instrument to solve the problem. This correlation manifests a very strong dependence both on the solar cycle phase and heliolatitude. It seems reasonable that the effectiveness of the mechanisms depends strongly on the relative area of low and high (including open field) loops. The models based on slow field dissipation (DC) are more effective in the low-latitude zone and the wave models based on dissipation of Alfven waves (AC), in the high latitude zone. Title: Correlation between the near-Earth solar wind parameters and the source surface magnetic field Authors: Belov, A. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2006Ge&Ae..46..430B Altcode: No abstract at ADS Title: Long-term variations of galactic cosmic rays in the past and future from observations of various solar activity characteristics Authors: Belov, A. V.; Gushchina, R. T.; Obridko, V. N.; Shelting, B. D.; Yanke, V. G. Bibcode: 2006JASTP..68.1161B Altcode: 2006JATP...68.1161B The previously proposed model of cosmic-ray (CR) modulation in the heliosphere, which considers the relationship between long-term CR variations and parameters of the solar magnetic field, has been used to estimate the observed CR variations in the near-Earth space with accuracy allowing their prediction. It is shown that there are two possibilities: (1) to predict CR intensity for 1 6 months by using the delay of CR variations relative to the solar-activity (SA) effects and (2) to predict CR intensity for the next solar cycle. In the second case, prediction of the global solar magnetic field characteristics is crucial. Reliable long-term CR and SA data are necessary in both cases. CR variations for the next solar cycle are predicted by statistical method using solar magnetic field data from two magnetographs (Stanford and Kitt Peak). The CR behavior during centuries 17 20 has been reconstructed on the basis of a model relating CR modulation to solar and geomagnetic activity indices. Title: The All-Russia conference on the Experimental and Theoretical Basis of Forecasting Heliogeophysical Activity Organized by the Solar Section of the Scientific Council of the Russian Academy of Ciences on Astronomy and the Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation, Russian Academy of Sciences (October 10 15, 2005, Troitsk) Authors: Kuznetsov, V. D.; Obridko, V. N. Bibcode: 2006SoSyR..40..262K Altcode: No abstract at ADS Title: Calculation of the interplanetary magnetic field based on its value in the solar photosphere Authors: Obridko, V. N.; Shelting, B. D.; Kharshiladze, A. F. Bibcode: 2006Ge&Ae..46..294O Altcode: No abstract at ADS Title: Cyclic variations in the differential rotation of the solar corona Authors: Badalyan, O. G.; Obridko, V. N.; Sýkora, J. Bibcode: 2006ARep...50..312B Altcode: The rotation of the solar corona is analyzed using the original database on the brightness of the FeXIV 530.3 nm coronal green line covering six recent activity cycles. The rate of the differential rotation of the corona depends on the cycle phase. In decay phases, there are only small differences in the rotation, which are similar to that of a rigid body. The differences are more significant (though less pronounced than in the photosphere) during rise phases, just before maxima, and sometimes at maxima. The total rate of the coronal rotation is represented as a superposition of two, i.e., fast and slow modes. The synodic period of the fast mode is approximately 27 days at the equator and varies slightly with time. This mode displays weak differences in rotation and is most pronounced in the middle of decay phases. The slow mode is manifested only at high latitudes during the rise phases of activity, and displays a mean period of 31 days. The relative contribution of each mode to the total rotational rate is determined as a function of time and heliographic latitude. These results indicate that the structure of the velocity field in the convective zone must also vary with time. This conclusion can be verified by helioseismology measurements in the near future. Title: Solar cycle according to mean magnetic field data Authors: Obridko, V. N.; Sokoloff, D. D.; Kuzanyan, K. M.; Shelting, B. D.; Zakharov, V. G. Bibcode: 2006MNRAS.365..827O Altcode: 2005MNRAS.tmp.1095O To investigate the shape of the solar cycle, we have performed a wavelet analysis of the large-scale magnetic field data for 1960-2000 for several latitudinal belts and have isolated the following quasi-periodic components: ~22, 7 and 2 yr. The main 22-yr oscillation dominates all latitudinal belts except the latitudes of +/-30° from the equator. The butterfly diagram for the nominal 22-yr oscillation shows a standing dipole wave in the low-latitude domain (|θ|<= 30°) and another wave in the sub-polar domain (|θ|>= 35°), which migrates slowly polewards. The phase shift between these waves is about π. The nominal 7-yr oscillation yields a butterfly diagram with two domains. In the low-latitude domain (|θ|<= 35°), the dipole wave propagates equatorwards and in the sub-polar region, polewards. The nominal 2-yr oscillation is much more chaotic than the other two modes; however the waves propagate polewards whenever they can be isolated.

We conclude that the shape of the solar cycle inferred from the large-scale magnetic field data differs significantly from that inferred from sunspot data. Obviously, the dynamo models for a solar cycle must be generalized to include large-scale magnetic field data. We believe that sunspot data give adequate information concerning the magnetic field configuration deep inside the convection zone (say, in overshoot later), while the large-scale magnetic field is strongly affected by meridional circulation in its upper layer. This interpretation suggests that the poloidal magnetic field is affected by the polewards meridional circulation, whose velocity is comparable with that of the dynamo wave in the overshoot layer. The 7- and 2-yr oscillations could be explained as a contribution of two sub-critical dynamo modes with the corresponding frequencies. Title: Interplanetary Magnetic Field Calculated from Photospheric Measurements Authors: Obridko, V. N.; Belov, A. V.; Shelting, B. D. Bibcode: 2005ESASP.600E...5O Altcode: 2005dysu.confE...5O; 2005ESPM...11....5O No abstract at ADS Title: Temporal Variations of the Solar Corona Rotation Authors: Badalyan, O. G.; Obridko, V. N.; Kora, J. S. Bibcode: 2005ESASP.600E..50B Altcode: 2005dysu.confE..50B; 2005ESPM...11...50B No abstract at ADS Title: Quasi-Biennial Oscillations in the N-S Asymmetry of Solar Activity Authors: Badalyan, O. G.; Obridko, V. N.; Sýkora, J. Bibcode: 2005ESASP.600E.152B Altcode: 2005dysu.confE.152B; 2005ESPM...11..152B No abstract at ADS Title: Some Fractal Properties of Solar Magnetic Fields Authors: Ioshpa, B.; Mogilevskii, E.; Obridko, V.; Rudenchik, E. Bibcode: 2005ESASP.596E..68I Altcode: 2005ccmf.confE..68I No abstract at ADS Title: Structure of Solar-Wind Streams at the Maximum of Solar Cycle 23 Authors: Lotova, N. A.; Vladimirskii, K. V.; Obridko, V. N.; Filippov, B. P.; Korelov, O. A. Bibcode: 2005AstL...31..546L Altcode: We study the formation of solar-wind streams in the years of maximum solar activity 2000 2002. We use observations of the scattering of radio emission by solar-wind streams at distances of ∼4 60R S from the Sun, data on the magnetic field structure and strength in the source region (R ∼ 2.5R S), and observations with the LASCO coronagraph onboard the SOHO spacecraft. Analysis of these data allowed us to investigate the changes in the structure of circumsolar plasma streams during the solar maximum. We constructed radio maps of the solar-wind transition, transonic region in which the heliolatitudinal stream structure is compared with the structure of the white-light corona. We show that the heliolatitudinal structure of the white-light corona largely determines the structure of the solar-wind transition region. We analyze the correlation between the location of the inner boundary of the transition region R in and the magnetic field strength on the source surface |B R|. We discuss the peculiarities of the R in = F(|B R|) correlation diagrams that distinguish them from similar diagrams at previous phases of the solar cycle. Title: Quasibiennial Oscillations of the North-South Asymmetry Authors: Badalyan, O. G.; Obridko, V. N.; Rybák, J.; Sýkora, J. Bibcode: 2005ARep...49..659B Altcode: The north-south (N-S) asymmetry of the solar activity (A), which reflects differences in the behavior of the northern and southern hemispheres of the Sun, is studied using data on the brightness of the coronal green line, the total number and area of sunspots, and the net magnetic flux. The spatial and temporal distributions and correlations between the A values represented by these indices are considered. The characteristic time variations in A are similar for all the indices, on both long and short time scales. Quasibiennial oscillations (QBOs) can be traced in the asymmetries of all four indices. A detailed study of the QBOs is carried out based on spectral-variation and wavelet analyses. Long-term increases and decreases occur synchronously in the asymmetries of various indices and are much more pronounced in A than in the indices themselves. A negative correlation between the power of the QBOs and the asymmetry of A can be traced; it is most clearly manifest as a substantial diminishing of the QBOs during the mid-1960s, which coincided with an especially strong increase in A. Our analysis shows that the N-S asymmetry is probably a fundamental property that controls the coupling and degree of coincidence between the magnetic-field-generation mechanisms operating in the northern and southern hemispheres. Title: Cyclic Variation in the Spatial Distribution of the Coronal Green Line Brightness Authors: Badalyan, O. G.; Obridko, V. N.; Sýkora, J. Bibcode: 2005ARep...49..477B Altcode: The spatial and temporal brightness distributions of the Fe XIV 530.3 nm coronal green line (CGL) and cyclic variations of these distributions are analyzed for a long time interval covering more than five 11-year cycles (1943 2001). The database of line brightnesses is visually represented in the form of a movie. Substantial restructuring of the spatial distribution of the CGL brightness occur over fairly short time intervals near the so-called reference points of the solar cycle; such points can be identified based on various sets of solar-activity indices. Active longitudes are observed in the CGL brightness over 1.5 3 yr. Antipodal and “alternating” active longitudes are also detected. The movie can be used to compare the CGL brightness data with other indicators of solar activity, such as magnetic fields. The movie is available at http://helios.izmiran.rssi.ru/hellab/Badalyan/green/. Title: On a probable model of solar flares based on an `avalanche' of self-organized criticality with energy and matter transport by magnetohydrodynamic solitons Authors: Mogilevskii, E. I.; Obridko, V. N.; Shilova, N. S. Bibcode: 2005A&AT...24...25M Altcode: The problem of energy transport by magnetohydrodynamic (MHD) solitons to the local region of a solar flare is considered within the framework of a new concept on the nature of solar flares as an effect of the unloading of matter and energy under self-organized criticality. The high-resolution observations (±1?) by the TRACE spacecraft are used. The characteristics of the small-scale discrete flare elements are shown to correspond to the properties of MHD solitons. Therefore, the above-mentioned concept represents conclusive evidence of the fractal-cluster structure of the solar magnetized plasma. Title: Prediction of expected global climate change by forecasting of galactic cosmic ray intensity time variation in near future based on solar magnetic field data Authors: Belov, A. V.; Dorman, L. I.; Gushchina, R. T.; Obridko, V. N.; Shelting, B. D.; Yanke, V. G. Bibcode: 2005AdSpR..35..491B Altcode: A method of prediction of expected part of global climate change caused by cosmic ray (CR) by forecasting of galactic cosmic ray intensity time variation in near future based on solar activity data prediction and determined parameters of convection-diffusion and drift mechanisms is presented. This gave possibility to make prediction of expected part of global climate change, caused by long-term cosmic ray intensity variation. In this paper, we use the model of cosmic ray modulation in the Heliosphere, which considers a relation between long-term cosmic ray variations with parameters of the solar magnetic field. The later now can be predicted with good accuracy. By using this prediction, the expected cosmic ray variations in the near Earth space also can be estimated with a good accuracy. It is shown that there are two possibilities: (1) to predict cosmic ray intensity for 1-6 months by using a delay of long-term cosmic ray variations relatively to effects of the solar activity and (2) to predict cosmic ray intensity for the next solar cycle. For the second case, the prediction of the global solar magnetic field characteristics is crucial. For both cases, reliable long-term cosmic ray and solar activity data as well as solar magnetic field are necessary. For solar magnetic field, we used results of two magnetographs (from Stanford and Kitt Peak Observatories). The obtained forecasting of long-term cosmic ray intensity variation we use for estimation of the part of global climate change caused by cosmic ray intensity changing (influenced on global cloudiness covering). Title: The relation of global magnetic solar field indices and solar wind characteristics with long-term variations of galactic cosmic rays Authors: Belov, A. V.; Gushchina, R.; Obridko, V. N.; Shelting, B. D.; Yanke, V. G. Bibcode: 2005ICRC....2..235B Altcode: 2005ICRC...29b.235B No abstract at ADS Title: Solar Magnetic Fields and the Intensity of the Green Coronal Line Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 2004ARep...48..678B Altcode: Synoptic maps of the intensity of the λ530.5 nm FeXIV green coronal line and maps of computed coronal magnetic fields for the period 1977 2001 are compared. For quantitative comparisons, the correlation coefficients r for the correlation between these two parameters at corresponding points of the synoptic maps are calculated. This coefficient exhibits cyclic variations in the spot-formation zone, ±30° and the zone above 30° and is in antiphase in these two zones. In the low-latitude zone, the correlation coefficient is always positive, reaches its maximum at activity minimum, and strongly decreases by activity maximum. Above 30°, r reaches maximum positive values at activity maximum and then gradually decreases, passing through zero near the beginning of the phase of activity minimum and becoming negative during this phase. A Fourier analysis of r as a function of time reveals a wavelike variation with a period close to 1.3 yr (known also from helioseismological data for the tachoclinic region of magnetic-field generation), as well as a pronounced wave with a period of about 5 yr. The latitude dependence of r seems to be related to variations in the contributions from local, large-scale, and global fields. Our analysis suggests an approach to studying the complex problem of mechanisms for coronal heating. Title: Space-time distributions of the coronal green-line brightness and solar magnetic fields Authors: Badalyan, O. G.; Obridko, V. N.; Sýkora, J. Bibcode: 2004A&AT...23..555B Altcode: The space-time distribution of brightness of the Fe XIV, 530.3 nm coronal green line and its cyclic variations are analysed for a long time interval of more than five cycles (1943-2001). For this purpose a special movie has been made. It is shown that a substantial spatial reorganization of the coronal green-line brightness (CGLB) takes a relatively short time and occurs close to the so-called reference points of the cycle, as derived from the series of various solar activity indices. The ‘active longitudes’ lasting for 1.5-3.0 years are found to exist in the CGLB. The antipodal and ‘intermittent’ active longitudes are identified. For the time interval 1977-2001, it has been corroborated that the CGLB is strongly influenced by the magnetic field strength. An agreement is shown to exist between the spatial structure on the CGLB synoptic charts and those of the magnetic field strength. It is shown that the nature of the relationship between the CGLB and the magnetic field strengths in the corona inside and outside the sunspot formation zone differ significantly. Title: Reproducible Characteristics of the Solar Wind Acceleration Authors: Lotova, N. A.; Vladimirskii, K. V.; Obridko, V. N.; Subaev, I. A. Bibcode: 2004AstL...30..343L Altcode: In experiments that were regularly carried out in 1999-2002 with Pushchino radio telescopes (Russian Academy of Sciences), the study of the radial dependence of the scattering of radio emission from compact natural sources was extended to regions of circumsolar plasma farther from the Sun. Based on a large body of data, we show that, apart from the standard transonic acceleration region located at distances of 10-40 Rsolar from the Sun, there is a region of repeated acceleration at distances of 34-60 Rsolar attributable to the equality between the solar wind velocity and the Alfvenic velocity. The repetition in the trans-Alfvenic region of the characteristic features of the radial stream structure observed in the transonic region (the existence of a precursor, a narrow region of reduced scattering that precedes a wide region of enhanced scattering) suggests that the main characteristic features of the resonant acceleration of solar wind streams are preserved up to distances of the order of 60 Rsolar. Title: Multiparameter Computations of Solar Wind Characteristics in the Near-Earth Space from the Data on the Solar Magnetic Field Authors: Obridko, V. N.; Shelting, B. D.; Kharshiladze, A. F. Bibcode: 2004SoSyR..38..228O Altcode: 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. Title: Relationship between the coronal green line brightness and magnetic field strength Authors: Badalyan, Olga G.; Obridko, V. N. Bibcode: 2004IAUS..223..371B Altcode: 2005IAUS..223..371B The quantitative relation between the brightness of the coronal green line 530.5 nm Fe XIV and the magnetic field strength is considered over the 1977-2001 period. It is found that the correlation coefficients between these two parameters calculated separately inside and outside the sunspot formation zone pm 30^{circ} have cyclic variation and occur in anti-phase. This suggests different mechanisms of formation of the corona in the fields of small, medium, and large scales. These results can be used for quantitative verification of the corona heating models. Title: Cyclic variations in distribution of the coronal green line brightness and solar magnetic field Authors: Badalyan, Olga G.; Obridko, V. N.; Sýkora, J. Bibcode: 2004IAUS..223...69B Altcode: 2005IAUS..223...69B Cyclic variations of the coronal green line brightness (CGLB) are investigated analysing a series of synoptic charts and a special movie assembled of them, covering 1943-2001. Regular changes of the large-scale CGLB distribution in dependence on the phase in the solar cycle are presented. A quantitative relation between the coronal green line intensity I and the total magnetic field strength B is derived for the period 1977-2001; the B was calculated under potential approximation. A simple exponential relation of type I propto B^q was found to exist between the above two quantities. It is shown that the q exponent may have opposite sign in the equatorial and polar zones. During phases of the solar cycle maxima the I versus B relation is much more complicated and cannot be expressed by such a simple formula. Title: Magnetic Field Structure in Sunspots Authors: Ioshpa, B. A.; Mogilevskii, E. I.; Obridko, V. N.; Rudenchik, E. A. Bibcode: 2004IAUS..223..259I Altcode: 2005IAUS..223..259I The paper deals with some structural characteristics of sunspot magnetic fields. Title: Forecasting of galactic cosmic ray intensity based on solar magnetic field data Authors: Belov, A. V.; Dorman, L. I.; Gushchina, R. T.; Obridko, V. N.; Shelting, B. D.; Yanke, V. G. Bibcode: 2004cosp...35.4184B Altcode: 2004cosp.meet.4184B In Dorman (2004) it was made estimation of long-term cosmic ray intensity variation in near future based on solar activity data prediction and determined parameters of convection-diffusion and drift mechanisms. In the present paper we use the model of cosmic ray modulation in the Heliosphere which considers a relation between long-term cosmic ray variations with parameters of the solar magnetic field. The later now can be predicted with good accuracy. By using this prediction, the expected cosmic ray variations in the near Earth space also can be estimated with a good accuracy. It is shown that there are two possibilities: 1) to predict cosmic ray intensity for 1-6 months by using a delay of long-term cosmic ray variations relatively to effects of the solar activity and 2) to predict cosmic ray intensity for the next solar cycle. For the second case the prediction of the global solar magnetic field characteristics is crucial. For both cases reliable long-term cosmic ray and solar activity data as well as solar magnetic field are necessary. For solar magnetic field we used results of two magnetographs (Stanford and Kitt Peak). The obtained results we compare with obtained by different method in Dorman (2004). References: Dorman L.I. ``Prediction of galactic cosmic ray intensity variation for few (up to 10-12) years ahead on the basis of convection-diffusion/drift model and data on solar activity''. Report on Session PSW1 of COSPAR-2004. Title: Regularities of formation of supersonic solar wind Authors: Lotova, N.; Vladimirskii, K.; Obridko, V.; Subaev, I. Bibcode: 2004cosp...35.1244L Altcode: 2004cosp.meet.1244L In the regular experiments carried out with the RAS radio telescopes at Pushchino during 1999-2002, the study of the radial dependence of scattering of compact natural radio sources was extended to remote regions of the solar plasma environment. A vast statistical database was accumulated. The analysis of the data shows that, in addition to the well-known transonic acceleration region at a distance of 10-40 Rs from the Sun, a secondary acceleration region exists at 34-60 Rs, being due to the coincidence of the solar wind and Alfven velocities. The stream in the transalfvenic region displays the same typical radial structure as observed in the transonic region, i.e., the existence of a "precursor" - a narrow band of reduced scattering preceding a wide region of enhanced scattering. It implies that the main features of resonance acceleration of the solar wind streams are conserved at the distances of the order of 60 Rs. Title: Regularities of formation of supersonic solar wind Authors: Lotova, N.; Vladimirskii, K.; Obridko, V.; Subaev, I. Bibcode: 2004cosp...35..352L Altcode: 2004cosp.meet..352L In the regular experiments carried out with the RAS radio telescopes at Pushchino during 1999-2002, the study of the radial dependence of scattering of compact natural radio sources was extended to remote regions of the solar plasma environment. A vast statistical database was accumulated. The analysis of the data shows that, in addition to the well-known transonic acceleration region at a distance of 10-40 Rs from the Sun, a secondary acceleration region exists at 34-60 Rs, being due to the coincidence of the solar wind and Alfven velocities. The stream in the transalfvenic region displays the same typical radial structure as observed in the transonic region, i.e., the existence of a "precursor" - a narrow band of reduced scattering preceding a wide region of enhanced scattering. It implies that the main features of resonance acceleration of the solar wind streams are conserved at the distances of the order of 60 Rs. Title: Prediction of expected global climate change by forecasting of galactic cosmic ray intensity time variation in near future based on solar magnetic field data Authors: Belov, A. V.; Dorman, L. I.; Gushchina, R. T.; Obridko, V. N.; Shelting, B. D.; Yanke, V. G. Bibcode: 2004cosp...35.3913B Altcode: 2004cosp.meet.3913B In Dorman (2004) it was made estimation of long-term cosmic ray intensity variation in near future based on solar activity data prediction and determined parameters of convection-diffusion and drift mechanisms. This gave possibility to made prediction of expected part of global climate change, caused by long-term cosmic ray intensity variation. In this paper we use the model of cosmic ray modulation in the Heliosphere which considers a relation between long-term cosmic ray variations with parameters of the solar magnetic field. The later now can be predicted with good accuracy. By using this prediction, the expected cosmic ray variations in the near Earth space also can be estimated with a good accuracy. It is shown that there are two possibilities: 1) to predict cosmic ray intensity for 1-6 months by using a delay of long-term cosmic ray variations relatively to effects of the solar activity and 2) to predict cosmic ray intensity for the next solar cycle. For the second case the prediction of the global solar magnetic field characteristics is crucial. For both cases reliable long-term cosmic ray and solar activity data as well as solar magnetic field are necessary. For solar magnetic field we used results of two magnetographs (Stanford and Kitt Peak). The obtained by described method prediction on long-term cosmic ray intensity variation we used for estimation of expected part of global climate change caused by cosmic rays. These results we compare with obtained by different method in Dorman (2004). References: Dorman L.I. ``Estimation of long-term cosmic ray intensity variation in near future and prediction of expected global climate change''. Report on Session D2.1/C2.2/E3.1 of COSPAR-2004. Title: Global Solar Magnetology and Reference Points of the Solar Cycle Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2003ARep...47..953O Altcode: The solar cycle can be described as a complex interaction of large-scale/global and local magnetic fields. In general, this approach agrees with the traditional dynamo scheme, although there are numerous discrepancies in the details. Integrated magnetic indices introduced earlier are studied over long time intervals, and the epochs of the main reference points of the solar cycles are refined. A hypothesis proposed earlier concerning global magnetometry and the natural scale of the cycles is verified. Variations of the heliospheric magnetic field are determined by both the integrated photospheric i(B r )ph and source surface i(B r )ss indices, however, their roles are different. Local fields contribute significantly to the photospheric index determining the total increase in the heliospheric magnetic field. The i(B r )ss index (especially the partial index ZO, which is related to the quasi-dipolar field) determines narrow extrema. These integrated indices supply us with a “passport” for reference points, making it possible to identify them precisely. A prominent dip in the integrated indices is clearly visible at the cycle maximum, resulting in the typical double-peak form (the Gnevyshev dip), with the succeeding maximum always being higher than the preceding maximum. At the source surface, this secondary maximum significantly exceeds the primary maximum. Using these index data, we can estimate the progression expected for the 23rd cycle and predict the dates of the ends of the 23rd and 24th cycles (the middle of 2007 and December 2018, respectively). Title: Solar Wind Sources and Flow Structure Over the 1995-2000 Period Authors: Lotova, N. A.; Obridko, V. N.; Vladimirsky, K. V. Bibcode: 2003AIPC..679..110L Altcode: Evolution of the large-scale stream structure of the solar wind flow is studied in the main acceleration zone at 10 to 40 solar radii from the Sun. Three independent sets of the experimental data were used: observations of the radio wave scattering using the large radio telescopes of the Lebedev Physical Institute, white solar corona images obtained with the SOHO spacecraft, and solar magnetic field strength computed from J.Wilcox Solar Observatory data. The positions of the transonic region of the solar wind flow derived from the radio astronomical observations data were used as a parameter reflecting the intensity of the solar wind acceleration process. Correlation studies of these data with the magnetic field strength in the solar corona permit us to reveal several different types of the solar wind streams. The 1995-2000 data show important changes in the solar corona magnetic fields and corresponding changes of the solar wind flow. Title: The role of meridional circulation in generating the 22-year solar cycle Authors: Ivanov, E. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2003ESASP.535...37I Altcode: 2003iscs.symp...37I The role of meridional circulation in generating the 22-year cycle of solar magnetic fields and sunspots has been analysed. The proposed model is based on the study of cyclic evolution of local and large-scale fields: direction and duration of their heliolatitude drift, and phase ratio of their maximum intensities. It is shown that the drift from the equator to the poles occurs for 16-17 years, as well as the backward drift from the poles to the equator at the base of the convection zone. Thus, the total cycle of the meridional circulation of solar magnetic fields is 32-34 years. Title: N-S asymmetry of solar activity and quasi-biennial oscillations Authors: Badalyan, O. G.; Obridko, V. N.; Rybák, J.; Sýkora, J. Bibcode: 2003ESASP.535...63B Altcode: 2003iscs.symp...63B Space-time distribution and mutual correlation of the N-S asymmetry in various indices of solar activity are considered. It is shown that changes in the N-S asymmetry variation both at short and long time scales are consonant in all activity indices under consideration. Quasi-biennial variations of the asymmetry index and their space-time distribution are revealed and examined. The conclusion can be drawn that the N-S asymmetry is a specific independent and very promising tool for analysis of the solar activity variations. Title: Foreword (Solar variability as an input to the Earth's environment) Authors: Wu, T.; Obridko, V.; Schmieder, B.; Sykora, J. Bibcode: 2003ESASP.535D..17W Altcode: 2003iscs.sympD..17W No abstract at ADS Title: Slow Solar Wind: Sources and Components of the Stream Structure at the Solar Maximum Authors: Vladimirsky, K. V.; Lotova, N. A.; Obridko, V. N. Bibcode: 2003AstL...29..629V Altcode: We study the sources and components of the solar-wind spatial stream structure at the maximum of the solar cycle 23. In our analysis, we use several independent sets of experimental data: radio-astronomical observations of scattered radiation from compact sources with the determination of the distance from the Sun to the inner boundary of the transonic-flow transition region (R_in); calculated data on the magnetic-field intensity and structure in the solar corona, in the solar-wind source region, obtained from optical measurements of the photospheric magnetic-field intensity at the Stanford Solar Observatory (USA); and observations of the white-light corona with the LASCO coronograph onboard the SOHO spacecraft. We show that at the solar maximum, low-speed streams with a transition region located far from the Sun dominate in the solar-wind structure. A correlation analysis of the location of the inner boundary R_in and the source-surface magnetic-field intensity |B_R| on a sphere R = 2.5 R_solar is revealed the previously unknown lowest-speed streams, which do not fit into the regular relationship between the parameters R_in and |B_R|. In the white-light corona, the sources of these streams are located near the dark strip, a coronal region with a greatly reduced density; the nonstandard parameters of the streams probably result from the interaction of several discrete sources of different types. Title: The Global Cooperation in Solar-Terrestrial Physics as the base for development of national programs in Russia: retrospect and prospect. Authors: Zaitzev, A.; Kozlov, A.; Obridko, V. Bibcode: 2003EAEJA....12781Z Altcode: The International Geophysical Year (IGY, 1957-1958) was the global coordination program that leads to develop of scientific collaboration in the world. IGY was based on the previous experience gained during International Polar Years. The most remarkable point for IGY was the first Sputnik that opens the space era. Since that we count direct outer space exploration. The combination of ground-based and satellite observations lead to form of a new science Solar-Terrestrial Physics. Since IGY we have the period of intensive development of STP in Russia, which include many programs and projects. In 1957-1963 we gain two main results: the network of research institutes and observatories as well as many space probes as COSMOS-49, COSMOS-321 etc. The leading role in developing of STP since IGY till nowadays belongs to IZMIRAN (Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation Russian Academy of Sciences). First director of IZMIRAN Prof. Nikolay Pushkov (1903-1981) strongly advocate for international cooperation and was one of the key figure in IGY. In May 2003 we celebrate his 100th birthday on special Symposium, which will be held in IZMIRAN. During past 45 years it was built and sent into space many space instruments including magnetometers, ionospheric sounders, VLF sensors, etc. Last satellite is CORONAS-F , which launched at July31, 2001 and successfully operate now. On the international scene all experimental space research coordinated by COSPAR and solar-terrestrial physics coordinated by SCOSTEP. In a new born Russia the COSPAR partner is Space Research Institute and for SCOSTEP is Sun-Earth Scientific Council. As the recent achievement in the area of STP in Russia we might consider INTERBALL program. The progress in STP based also on the usage of Internet as the data storage with remote on-line access, with the system for search and exchange of information, and with search engines in Russian language. At nowadays we have more than 300 sites devoted to STP in Russian Internet among them as Space Research Institute (www.iki.rssi.ru), IZMIRAN (www.izmiran.rssi.ru), ISZF (www.iszf.irk.ru), NIIYAF (www.npi.msu.su). To refer a proposal for IHY/IPY program we can confirm that in Russia we have a good number of national projects, which might be considered as the starting point. After governmental approval to take part in the IHY/IPY programs Russian scientist will joint to the world community. From our personal viewpoint we strongly advocate in favor to take part in IHY/IPY programs on the base of previous experience. The part of this work was supported by Russian Fund of Basic Research (grant # 02-07-90232). Title: Meridional Drift of Large-Scale Solar Magnetic Fields Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2003ARep...47..333O Altcode: It is shown that the meridional drift of large-scale fields starts in the equatorial zone and continues over 15 16 yrs (16 17 according to another estimate), i.e., during three fourths of the 22-year cycle. There is an abrupt retardation of the drift at latitudes of 30° 50°, and a stagnation region where the drift rate does not exceed several meters per second arises. The drift becomes rapid again at higher latitudes. The stagnation region coincides with the area in which the radial gradient of the rotational velocity is close to zero in the convective zone. This drift is compared with helio-seismological data on the rotation in the convective zone. A model taking into account some elements of dynamo theory is proposed. Title: Integral Properties of Solar Active Regions Authors: Chumak, O.; Obridko, V.; Zhang, H.; Ai, G.; Utrobin, V.; Krasotkin, S. Bibcode: 2003A&AT...22..335C Altcode: In the paper the results of investigations on ten solar active regions are presented. The main results are as follows: firstly, the total down-flow velocity exceeds the up-flow velocity by about two orders of magnitude in all the active regions; secondly, no correlation was found between the mean integral velocity flux and the mean integral magnetic flux for all the active regions; thirdly, it was found that, besides a direct correlation between the total sunspot area and the total magnetic flux in active regions, occasionally there is an inverse correlation between these parameters, and the inverse correlation times often corresponded to the structural and topological rebuilding of magnetic flux in the active regions; fourthly, a good correlation was found between some parameters of integral fluxes (magnetic and velocity) and X-ray flux variations. Title: Connections Between the White-Light Eclipse Corona and Magnetic Fields over the Solar Cycle Authors: Sýkora, J.; Badalyan, O. G.; Obridko, V. N. Bibcode: 2003SoPh..212..301S Altcode: Observations of ten solar eclipses (1973-1999) enabled us to reveal and describe mutual relations between the white-light corona structures (e.g., global coronal forms and most conspicuous coronal features, such as helmet streamers and coronal holes) and the coronal magnetic field strength and topology. The magnetic field strength and topology were extrapolated from the photospheric data under the current-free assumption. In spite of this simplification the found correspondence between the white-light corona structure and magnetic field organization strongly suggests a governing role of the field in the appearance and evolution of local and global structures. Our analysis shows that the study of white-light corona structures over a long period of time can provide valuable information on the magnetic field cyclic variations. This is particularly important for the epoch when the corresponding measurements of the photospheric magnetic field are absent. Title: IZMIRAN Solar Spectromagnetograph Authors: Kozhevatov, I. E.; Cheragin, N. P.; Kulikova, E. N.; Ioshpa, B. A.; Obridko, V. N.; Rudenchik, E. A.; Nepomnyashchy, V. Yu. Bibcode: 2003ASPC..307...62K Altcode: No abstract at ADS Title: Quasi-biennial oscillations of the solar magnetic fields Authors: Ivanov, E. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2002ESASP.506..847I Altcode: 2002svco.conf..847I; 2002ESPM...10..847I Quasi-biennial oscillations (QBO) are mainly revealed in the structure of large-scale solar magnetic fields (LSMF). In the medium-scale fields, they are weak. QBO are well-pronounced in the time-latitude diagrams and correlograms, as well as in the spectra of the source-surface magnetic field sector structure. Thus, QBO are actually variations of the equatorial dipole and quadrupole. QBO are also clearly seen in the indices characterizing the asymmetry of the LSMF parameters. The QBO intensity in LSMF changes with time, being maximum in the middle of the 20th century. The relationship between QBO in LSMF and the cycle reference points is investigated. Title: Meridional drifts of large-scale solar magnetic fields and meridional circulation Authors: Ivanov, E. V.; Obridko, V. N.; Shelting, B. D. Bibcode: 2002ESASP.506..851I Altcode: 2002svco.conf..851I; 2002ESPM...10..851I The meridional drifts of local (LF) and large-scale (LSMF) solar magnetic fields has been studied for the time interval 1960-2000. The LSMF meridional drift velocity has been considered as a function of latitude. Two modes have been discovered in the meridional poleward drift of LSMF with the typical equator-to-pole travel times of 16-18 and 2-3 years. It is shown that the variation in the square values of the solar field radial component on the time-latitude diagrams coincides with the equatorward drift of local magnetic fields (LF). A shift by 5-5.5 years is observed in the intensity maxima of the global and local fields. It is shown that the total period of meridional circulation of solar plasma in the convection zone is ~22 years, i.e. is equal to the Hale magnetic cycle. Title: New Izmiran solar spectromagnetograph Authors: Kozhevatov, I. E.; Cheragin, N. P.; Ioshpa, B. A.; Kulikova, E. H.; Obridko, V. N.; Rudenchik, E. A. Bibcode: 2002ESASP.506..951K Altcode: 2002svco.conf..951K; 2002ESPM...10..951K A new solar spectromagnetograph for measuring the full magnetic-field vector and line-of-sight velocities is described. A new version of a polarization analyzer ensuring parallel measurements of six polarization components of spectral lines is considered. The spectromagnetograph allows the use of any algorithms for obtaining the magnetic fields vector, in particular, the Babcock algorithm and the Fourier transform technique. The sensitivity of the instrument for the longitudinal and transverse magnetic field is 5-10 and 30-50 G, respectively, and ~10 m/s for the line-of-sight velocities. Title: Polarization in the 530.3nm emission line and coronal magnetic field structure Authors: Badalyan, O. G.; Obridko, V. N.; Sýkora, J. Bibcode: 2002CoSka..32..175B Altcode: To clarify the possible influence of the coronal magnetic field on the degree of polarization p, direction of polarization β, and line intensity Iλ measured during the 11 July 1991 total solar eclipse, we have compared these quantities with different field parameters. The structure of the coronal magnetic field on the eclipse day was calculated using potential approximation. The relation of p and Iλ as measured at 1.2 RSun from the centre of the solar disk to the strength of the magnetic field and its different components is discussed in detail. It is found that the points pertinent to the large-scale coronal structures of different morphological (physical) types (high-latitude streamers, bright equatorial regions, regions in the vicinity of coronal holes, etc.) form isolated, not overlapping clusters of points on the B -- p, B -- β and B -- log Iλ diagrams. Two classes of objects are distinct in these diagrams. The first class comprises of high-latitude streamers in which the degree of polarization increases with decreasing B. The second class is represented by coronal condensations, moderately active equatorial regions, and coronal holes. In the objects of this class, the magnetic field strength is approximately three times as large as in the streamers, and the degree of polarization depends only weakly on B. It is shown that p, Iλ and β display a noticeable relationship with the indices Q1 and Q2, which we introduced to characterize the complexity (degree of inhomogeneity) of the magnetic field at any given point in the solar corona. In fact, Q1 and Q2 represent the absolute and relative deviations of B from its mean value measured in the neighbourhood of a given point. The results of our investigation suggest that we are dealing with the direct influence of the magnetic field on the generation of the polarized radiation in the λ 530,3nm emission line. One can expect, therefore, that the investigation of polarization characteristics would provide a useful method for determining the magnetic field in the solar corona. Title: ASTRONOMY OF ANCIENT CIVILIZATIONS: The International Conference of the European Society for Astronomy in Culture - SEAC, Moscow, 2000 Authors: Obridko, V. N.; Potyomkina, T. M.; Lushnikova, A. V.; Pustylnik, I. B.; Chepurova, V. M. Bibcode: 2002A&AT...21..279O Altcode: Available from http://taylorandfrancis.metapress.com/openurl.asp?genre=article&issn=1055-6796&volume=21&issue=4&spage=279 Title: Three Types of Flows in the Structure of the Solar Wind Authors: Lotova, N. A.; Obridko, V. N.; Vladimirskii, K. V. Bibcode: 2002ARep...46..339L Altcode: An experimental study of the source and formation of large-scale streams in the solar wind is presented. Radio-astronomical data from 1998 are compared with optical SOHO observations and solar coronal magnetic fields calculated from Zeeman data obtained at the Wilcox Observatory. A correlation between the geometry of the solar-wind transition region and the strength of coronal magnetic fields is revealed. For the moderate heliolatitudes studied, this correlation divides into three branches corresponding to three types of coronal magnetic-field structures: open structures with field lines escaping into interplanetary space, closed structures with loop-like field lines, and intermediate structures including both open and closed configurations. High-speed streams of solar wind originate in regions with open magnetic structures. These structures are connected with the lateral lobes of streamers at moderate heliolatitudes. Low-speed flows originate above closed magnetic structures, typical of the main bodies of streamers. The lowest-speed solar-wind flows are not associated with coronal streamer structures, and originate in coronal regions with intermediate magnetic configurations simultaneously containing open and closed field lines. In these regions, the white-light corona becomes an extended and amorphous area with high luminosity, which stratifies into a radial structure with narrow stripes at higher resolution. Title: Increase of the Magnetic Flux From Polar Zones of the sun in the Last 120 Years Authors: Makarov, V. I.; Tlatov, A. G.; Callebaut, D. K.; Obridko, V. N. Bibcode: 2002SoPh..206..383M Altcode: Lockwood, Stamper, and Wild (1999) argued that the average strength of the magnetic field of the Sun has doubled in the last 100 years. They used an analysis of the geomagnetic index «aa». We calculated the area of polar zones of the Sun, Apz, occupied by unipolar magnetic field on Hα synoptic magnetic charts, following Makarov (1994), from 1878 to 2000. We found a gradual decrease of the annual minimum latitude of the high-latitude zone boundaries, θ2m, of the global magnetic field of the Sun at the minimum of activity from 53° in 1878 down to 38° in 1996, yielding an average decrease of 1.2° per cycle. Consequently the area of polar zones Apz of the Sun, occupied by unipolar magnetic field at the minimum activity, has risen by a factor of 2 during 1878-1996. This means that the behavior of the index «aa» and consequently the magnetic flux from the Sun may be explained by an increase of the area of polar caps with roughly the same value of the magnetic field in this period. The area of the unipolar magnetic field at the poles (Apz) may be used as a new index of magnetic activity of the Sun. We compared Apz with the «aa», the Wolf number «W» and «A»* -index (Makarov and Tlatov, 2000). Correlations based on `11-year' averages are discussed. A temperature difference of about 1° between the Maunder Minimum and the present time was deduced. We have found that the highest latitude of the polar zone boundaries of the large-scale magnetic field during very low solar activity reaches about 60°, cf., the Maunder Minimum. It is supposed that the θ2m-latitude coincides with the latitude where ∂rω=0, with ω(r,θ) being the angular frequency of the solar rotation. The causes of the waxing and waning of the Sun's activity in conditions like Maunder Minimum are discussed. Title: Direction of the coronal green line polarization as derived from the eclipse measurements Authors: Badalyan, O. G.; Obridko, V. N.; Sykora, J. Bibcode: 2002CoSka..32...49B Altcode: Investigation of the polarization in the coronal FeXIV lambda 530.3 nm line is continued by exploiting the 11 July 1991 eclipse observation. In this paper, we analyze the direction of the plane of polarization represented by deviations of the magnetic vector from the radial directions -- angle beta. The relation of this angle to the other polarization charcteristics is discussed. It has been found that beta is small in the coronal features characterized by a high degree of polarization (streamers and coronal holes). With the decreasing polarization (e.g., when the equatorial objects of enhanced activity are considered) the magnitude of beta increases significantly. The extreme values of beta are observed within the coronal features related to the active regions in the photosphere. The distribution of beta in magnitude is distinctly shifted from zero to positive values. This means that, in the most part of the corona on July 11, 1991, the magnetic vector deviates from radiality clockwise. In connection with the revealed drastic discrepancy between the observed direction of the plane of polarization and the generally accepted theoretical conceptions (Badalyan et al., 2001; Badalyan, 2002), the obtained result may be worth considering when developing a new theory of the origin of polarized radiation in the coronal green line. Title: Secular and cycle variations of the IMF Bz component and some associated geophysical effects Authors: Obridko, V. N.; Golyshev, S.; Levitin, A. E. Bibcode: 2002ESASP.477..405O Altcode: 2002scsw.conf..405O It is shown that the sign and amplitude of the annual mean Bz component of the interplanetary magnetic field (IMF) conforms with the structure of the large-scale solar magnetic field at the poles. Therefore, the recurrence of geomagnetic activity is best pronounced in the cycles when the polar field in the Sun is positive. Title: Zonal structure and meridional drift of large-scale solar magnetic fields Authors: Ivanov, E. V.; Obridko, V. N. Bibcode: 2002SoPh..206....1I Altcode: Digitized synoptic charts of photospheric magnetic fields were analyzed for the past 4 incomplete solar activity cycles (1969-2000). The zonal structure and cyclic evolution of large-scale solar magnetic fields were investigated using the calculated values of the radial Br, |Br|, meridional Bθ, |Bθ|, and azimuthal Bφ, |Bφ| components of the solar magnetic field averaged over a Carrington rotation (CR). The time-latitude diagrams of all 6 parameters and their correlation analysis clearly reveal a zonal structure and two types of the meridional poleward drift of magnetic fields with the characteristic times of travel from the equator to the poles equal to ∼16-18 and ∼2-3 years. A conclusion is made that we observe two different processes of reorganization of magnetic fields in the Sun that are related to generation of magnetic fields and their subsequent redistribution in the process of emergence from the field generation region to the solar surface. Redistribution is supposed to be caused by some external forces (presumably, by sub-surface plasma flows in the convection zone). Title: Long-term variations of polar magnetic flux of the Sun and terrestrial climate Authors: Makarov, V. I.; Tlatov, A. G.; Callebaut, D. K.; Obridko, V. N. Bibcode: 2002ESASP.477..563M Altcode: 2002scsw.conf..563M We calculated the area of polar zones of the Sun, Apz, occupied by unipolar magnetic field on Hα synoptic magnetic charts, following Makarov (1994), from 1878 to 2000. We found a gradual decrease of the annual latitude of the high-latitude zone boundaries of the global magnetic field of the Sun at the minimum of activity from 53° in 1878 down to 38° in 1996, yielding an average decrease of 1.2° per cycle. We found that the area of polar zones of the Sun Apz has risen by a factor of 2 during 1878-1996. The area of the unipolar magnetic field at high-latitudes Apz may be used as a new index of magnetic activity of the Sun. We compared Apz with the geomagnetic index and Wolf number. A temperature difference of about 1.3° between the Maunder Minimum and the present time was deduced. The causes of the waxing and waning of the Sun's activity in conditions like Maunder Minimum are discussed. Title: The North-South asymmetry of solar activity Authors: Badalyan, O. G.; Obridko, V. N.; Rybák, J.; Sýkora, J. Bibcode: 2002ESASP.477..201B Altcode: 2002scsw.conf..201B In the present paper the North-South (N-S) asymmetry of four solar activity indices is estimated and discussed. The coronal green line intensity measurements, the Wolf numbers and the sunspot area data - all of them were subjected to analysis over the 1943-1999 period, together with the NSO/KP data on the total magnetic field flux measured from 1975. The pair comparison of these four indices within different zones of solar latitude allowed to reveal a number of features in their mutual correlativness. As the coronal green line intensity as the sunspot area display a long-termed wave in their N-S asymmetry - about 40 years in duration. While during the first half of the interval studied the N-hemisphere dominates (with a clear maximum around 1964-66) then during the second half of the interval the activity measured over the S-hemisphere prevails. Quasi-biennial variations were identified both in the N-S asymmetry of the coronal green line brightness and that of the total magnetic flux. The performed study indicates a close relation between the global and local manifestations of solar activity, which are governed by the magnetic fields of different scales. Title: Long-term Galactic Cosmic Rays Variations and Their Relation With The Global Solar Magnetic Field Characteristics Authors: Belov, A. V.; Gushchina, R. T.; Obridko, V. N.; Shelting, B. D.; Yanke, V. G. Bibcode: 2002EGSGA..27.5528B Altcode: The rigidity spectrum of CR variations is evaluated from data of continuous monitor- ing of galactic cosmic rays (GCR), including ground based observations of neutron and general ionizing components by the network of CR stations, balloon and space- craft measurements of CR intensity in the stratosphere and the near space, for the whole period of the systematic CR ground based observations since 1953. Basing on these results the multi-parametric model of large scale GCR modulation by the solar activity in the heliosphere was elaborated (variations of particle density with 10 GV rigidity were considered). Characteristics of the global solar magnetic field on the so- lar wind source surface are main parameters of the model. Analyzing the model results it is possible to estimate a relative impact of each used indices accounting its delay to the observed CR modulation. A special method was used to account correctly the de- lay of solar-heliospheric characteristic effect on CR. The effect reveals a dependence on primary cosmic ray energy, an association with 11th and 22nd solar cycles. A solu- tion of this problem allows calculate CR variations with better accuracy and setup the problem of their prediction. A possibility of short-term predictions of GCR intensity by observations of particular CR stations, which data are available on Internet in real time, is considered in this work. A quality of such a prediction is discussed. Title: The role of the solar magnetic field systems in modulating the solar irradiance Authors: Ivanov, E. V.; Obridko, V. N. Bibcode: 2002AdSpR..29.1951I Altcode: Variations of indices that characterize various systems of the large-scale solar magnetic field (LSSMF) - magnetic field multipoles of different order, LSSMF energy index, index of the effective solar multipole, etc.- are compared with variations of the solar irradiance in different frequency ranges during 1978-1996. The role of the local and global magnetic fields in modulating the solar irradiance is investigated in various time intervals, in particular, in different phases of the 11-year solar cycle. Title: Development the Internet - Resources in Solar-Terrestrial Physics for the Science and Education Authors: Zaistev, A.; Ishkov, V.; Kozlov, A.; Obridko, V.; Odintsov, V. Bibcode: 2002rict.confE..27Z Altcode: Future development of research in the solar-terrestrial physics (STP) will motivated by needs into fundamental knowledge and the practical demands in the format of space weather. Public community realized that outer space disturbances affects on the operation of high technologies systems integrated into everyday life, so they need into Internet resources of solar-terrestrial physics as the open scientific and public domain. Recent achievements of STP lead to burst of data sources and we have now many different types of information available free in Internet: solar images from SOHO and GOES-12 satellites, WIND and ACE interplanetary data, satellite and ground-based magnetic field variations, aurora images in real time, ionospheric data and many more. In this paper we present some experience to establish in Russian language the open scientific and public domain in Internet which can served for better understanding of STP in wide scientific community and into the general public including different media sources. Now we have more than one hundred sites which present the STP data: Space Research Institute (www.iki.rssi.ru), IZMIRAN (www.izmiran.rssi.ru), Institute of Solar-Terrestrial Physics (www.iszf.irk.ru), Institute of Nuclear Physics in Moscow University (http://alpha.npi.msu.su) <A HREF="http://alpha.npi.msu.su"> Institute of Nuclear Physics in Moscow University </A>) and many more. Based on our own experience and our colleagues we decide to create information resources in solar-terrestrial physics as the open scientific and public domain. On this way the main directions of our activity as follows: to produce the catalogues of resources in Internet with detailed description of its content in Russian, to publish the list of Russian institutes working in STP, to present the biographical dictionary of Russian scientists in STP, to create the interactive forum for discussion of latest scientific results, to form the team of authors who willing to publish summarized analytical papers on the STP problems, to establish the regular newsletter with open circulation between professionals and people interested in STP, and to provide the scientific coordination between Russian institutes according rules of the road adopted by Solar-Terrestrial Scientific Council. We strongly advocate in favor to construct such Internet resources on native languages as it will served for national level due to its basic funding source. On the other hand our experience might be useful for other nations, as they are have the same aims. Our project have one of the goal to establish a better public understanding of STP through more open and wide public access to the latest scientific results. The realization of this project is supported by Russian Fund of Basic Research (grant N 02-07-90232) for period 2002-2004 and include results also supported by RFBR before. Title: Relationship between the coronal shape and the magnetic field topology during the solar cycle Authors: Sýkora, J.; Badalyan, O. G.; Obridko, V. N. Bibcode: 2002AdSpR..29..395S Altcode: We have observed ten solar eclipses during the 1973-1999 period, three of them being recorded during the rising phase of the present solar cycle 23. The observed shapes of the white-light corona are confronted with the magnetic field topology, as calculated for the corresponding eclipse days. A close relationship of the distinctive large-scale coronal structures (coronal streamers, coronal holes, polar plumes, etc.) with the calculated magnetic field structures and with the actual position of the heliospheric current sheet (as derived for the source surface at r = 2.5 R) is evident. The found relations suggest a new understanding of the coronal shape evolution during the solar cycle. It is shown that "the isogausses" and the coronal isophotes create two systems of mutually orthogonal curves. The nature of this finding is also well confirmed by estimating of the magnetic field strength inside the coronal holes observed during "our" eclipses. Title: Flow Sources and Formation Laws of Solar Wind Streams Authors: Lotova, N. A.; Obridko, V. N.; Vladimirskii, K. V.; Bird, M. K.; Janardhan, P. Bibcode: 2002SoPh..205..149L Altcode: The large-scale stream structure of the solar wind flow is studied in the main acceleration zone from 10 to 40 solar radii from the Sun. Three independent sets of experimental data were used: radio astronomical observations of radio wave scattering using the large radio telescopes of the Lebedev Physical Institute; dual-frequency Doppler solar wind speed measurements from the Ulysses Solar Corona Experiment during the spacecraft's two solar conjunctions in summer 1991 and winter 1995; solar magnetic field strength and configuration computed from Wilcox Solar Observatory data. Both the experimental data on the position of the transonic region of the solar wind flow and the solar wind speed estimates were used as parameters reflecting the intensity of the solar wind acceleration process. Correlation studies of these data with the magnetic field strength in the solar corona revealed several types of solar wind flow differing in their velocities and the location of their primary acceleration region. Title: Global magnetic field of the Sun and long-term variations of galactic cosmic rays Authors: Belov, A. V.; Shelting, B. D.; Gushchina, R. T.; Obridko, V. N.; Kharshiladze, A. F.; Yanke, V. G. Bibcode: 2001JASTP..63.1923B Altcode: 2001JATP...63.1923B The paper deals with the relation of long-term variations of 10GV galactic cosmic rays (GCR) to the global solar magnetic field and solar wind parameters. This study continues previous works, where the tilt of the heliospheric current sheet (HCS) and other solar-heliospheric parameters are successfully used to describe long-term variations of cosmic rays in the past two solar cycles. The novelty of the present work is the use of the HCS tilt and other parameters reconstructed from /Hα observations of filaments for the period when direct global solar magnetic field observations were unavailable. Thus, we could extend the GCR simulation interval back to 1953. The analysis of data for 1953-1999 revealed a good correlation (the correlation coefficient />0.88) between the solar-heliospheric parameters and GCR in different cycles of solar activity. Moreover, the approach applied makes it possible to describe the behavior of cosmic rays in the epochs of solar maxima, which could not be done before. This indicates both the adequacy of the model and the reliability of the reconstructed global solar magnetic field parameters. Title: Quasi-Biennial Oscillations of the Global Solar Magnetic Field Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2001ARep...45.1012O Altcode: Quasi-biennial oscillations (QBOs) can clearly be distinguished in uniform series of data on the solar magnetic-field polarity derived from Hα observations in 1915 1999. These have been proven to represent oscillations of the global magnetic field of the Sun. This is verified by spectral analyses executed using various methods: the QBOs are clearly visible in low harmonics (l=1 3), but abruptly disappear for l=4 and higher. First and foremost, the QBOs are displayed in variations of the sector structure of the large-scale magnetic field, demonstrating that they correspond to variations of the horizontal multipoles. Title: Quasi-biennial oscillations of the solar global magnetic field Authors: Shelting, B. D.; Obridko, V. N. Bibcode: 2001A&AT...20..491S Altcode: This work continues the series of papers analyzing the nature of the large-scale solar magnetic field (LSSMF) over a long time interval (1915-1990). We used the data inferred from observations of H filaments. SWAN and WAVELET analyses show that Quasibiennial Oscillations are connected with the lowest multipoles, in other words, with the global part of the LSSMF. For multipoles with number larger than 4 the power of the spectrum in the range of 2-3 years decreases abruptly. The LSSMF zonal and sectorial components (both odd and even) were calculated and the Fourier spectra were obtained. This allowed us to compare the amplitudes of different harmonics. Quasibiennial oscillations are best pronounced in the odd sectorial structures. QBO are absent at the cycle minima in the spectra based on the Stanford data (i.e., with the field strength taken into account). Contrary to that, QBO are of the same order over the entire time interval in the spectra based on H data (i.e., where the field structure is emphasized). Title: The increase in the magnetic flux from the polar regions of the Sun over the last 120 years Authors: Makarov, V. I.; Obridko, V. N.; Tlatov, A. G. Bibcode: 2001ARep...45..746M Altcode: The latitudes of the zonal boundaries of the global magnetic field of the Sun are determined from the magnetic neutral lines on synoptic Hα maps obtained during 1878 1999. The area of the polar zone occupied by magnetic field of a single polarity at solar minima has doubled over the last 120 years. This provides an explanation for the secular increase in heliospheric characteristics, which differs from the two-fold increase of the magnetic field strength predicted for this period. The temporal variations of the magnetic flux from the polar regions and their role in global changes of the Earth’s climate are discussed in connection with secular variations in the structure of the internal magnetic field of the Sun. Title: Flow Sources and Formation Laws of the Solar Wind Streams Authors: Lotova, N. A.; Obridko, V. N.; Vladimirskii, K. V.; Bird, M. K.; Janardhan, P. Bibcode: 2001hell.confE..18L Altcode: The large-scale stream structure of the solar wind flow is studied in the main acceleration zone from 10 to 40 solar radii from the Sun. Four independent sets of experimental data were used: radio astronomical observations of radio wave scattering using the large radio telescopes of the Lebedev Physical Institute; dual-frequency Doppler solar wind speed measurements from the Ulysses Solar Corona Experiment during the spacecraft's solar conjunctions in summer 1991 and winter 1995; solar magnetic field strength and configuration computed from Wilcox Solar Observatory data; white-light coronagraph images obtained from ground-based eclipse and SOHO observations. Both the experimental data on the position of the transonic region of the solar wind flow and the solar wind speed estimates were used as parameters reflecting the intensity of the solar wind acceleration process. Correlation studies of these data with the magnetic field strength in the solar corona revealed several types of solar wind flow. Different types of streams arise in coronal regions differing by their magnetic field strength and structure. A total of four specific types, two of high-speed and two of low-speed, were revealed. Title: Long-term variations of galactic cosmic rays and their relation with the solar magnetic field parameters Authors: Belov, A.; Gushchina, R.; Obridko, V.; Shelting, B.; Yanke, V. Bibcode: 2001ICRC...10.3911B Altcode: 2001ICRC...27.3911B The paper deals with the relation of long-term variations of galactic cosmic rays (CR) to the global solar magnetic field (GMF) and solar wind (SW) parameters. This study continues the series of work, where the tilt of the heliospheric current sheet (HCS) and other solarheliospheric parameters are successfully used to describe long-term variations of CR in the solar cycles. The novelty of the present work is the combined use of the source surface magnetic field characteristics, including HCS inclination, mean intensity of magnetic field and polarity of the global magnetic field. We take into account both the direct effect of polarity on CR variations and its effect on CR modulation related to the HCS tilt changes. The combined use of different solar parameters allows us to improve the model of long-term CR variations. The analysis of data for 1976-2000 has revealed a good correlation (the correlation coefficient 0.95) between the multi-parameter model and 10 GV galactic cosmic ray behavior during long period, spanning several cycles of solar activity. Title: Rotation Characteristics of Large-Scale Solar Magnetic Fields Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2001SoPh..201....1O Altcode: The rotation characteristics of large-scale (global) magnetic fields (GMF) and their relation to the activity of local fields (LMF) are studied over a long time interval (1915-1996). The main results are as follows. The GMF rotation rates and LMF activity vary in anticorrelation. Both variations have similar periods (11 years and a quasi-secular period of about 55-60 years), but are shifted relative to each other by half an 11-year cycle. Therefore, (1) the GMF rotation rate increases at the minimum of the 11-year cycle of LMF activity. (2) The GMF rotation rate is faster in the less active hemisphere. (3) The GMF rotation period slows down at the maximum of the secular LMF activity (cycles 18 and 19). Title: The Structure of the Photospheric Velocity Field near Hα Filaments Authors: Ioshpa, B. A.; Obridko, V. N. Bibcode: 2001ARep...45..409I Altcode: The velocity field of the plasma in the solar photosphere beneath chromospheric Hα filaments is studied. Observations were conducted in 1999 2000 using the magnetograph and tachometer of the tower telescope of the Institute of Terrestrial Magnetism, Ionosphere, and Radio Propagation, recently upgraded to improve both its sensitivity and spatial resolution. The results confirm that, as noted earlier, filaments are frequently found near velocity-inversion lines between regions of upward and downward motion of solar material, and lie predominantly above regions with upward motion of photospheric material. This tendency is characteristic of both the stable filaments of active regions and quiescent filaments far from active regions, though it is more distinct for the former case. The upward motion of photospheric material beneath filaments may play an important role in supporting the filaments against gravity. Title: Brightness of the Coronal Green Line and Prediction for Activity Cycles 23 and 24 Authors: Badalyan, O. G.; Obridko, V. N.; Sýkora, J. Bibcode: 2001SoPh..199..421B Altcode: Cyclic variations of the mean semi-annual intensities Iλ of the coronal green line λ530.3 nm are compared with the mean semi-annual variations of the Wolf numbers W during the period of 1943-1999 (activity cycles 18-23). The values of Iλ in the equatorial zone proved to correlate much better with the Wolf numbers in a following cycle than in a given one (the correlation coefficient r is 0.86 and 0.755, respectively). Such increase of the correlation coefficient with a shift by one cycle differs in different phases of the cycle, being the largest at the ascending branch. The regularities revealed make it possible to predict the behaviour of W in the following cycle on the basis of intensities of the coronal green line in the preceding cycle. We predict the maximum semi-annual W in cycle 23 to be 110-122 and the epoch of minimum between cycles 23 and 24 to take place at 2006-2007. A slow increase of Iλ in the current cycle 23 permits us to forecast a low-Wolf-number cycle 24 with the maximum W∼50 at 2010-2011. A scheme is proposed on the permanent transformation of the coronal magnetic fields of different scales explaining the found phenomenon. Title: Sector Structure, Rotation, and Cyclic Evolution of Large-Scale Solar Magnetic Fields Authors: Ivanov, E. V.; Obridko, V. N.; Ananyev, I. V. Bibcode: 2001SoPh..199..405I Altcode: Auto-correlation analysis was performed using digitized synoptic charts of photospheric magnetic fields for the past three solar activity cycles (1965-1994). The obtained correlograms were used to study the rotation and the zonal-sector structure of large-scale solar magnetic fields all over the observable region of heliolatitudes in various phases of solar activity. It is shown that the large-scale system of solar magnetic fields is rather complex and comprises at least three different systems. One is a global rigidly rotating system. It determines the cyclic variation of magnetic fields and is probably responsible for the behavior of magnetic fields in the polar zones. Another is a rigidly rotating 4-sector structure in the central (equatorial and mid-latitude) zone. The third is a differentially rotating system that determines the behavior of the LSSMF structure elements with a size of ∼ 30-60° and less. This one is the most noticeable in the central zone and absent in the polar zones. Various cyclic and rotation parameters of the three field structures are discussed. Title: Large-Scale Magnetic Field and Sunspot Cycles Authors: Makarov, V. I.; Tlatov, A. G.; Callebaut, D. K.; Obridko, V. N.; Shelting, B. D. Bibcode: 2001SoPh..198..409M Altcode: Hα magnetic synoptic charts of the Sun are processed for 1915-1999 and the spherical harmonics are calculated. It is shown that the polarity distribution of the magnetic field on Hα charts is similar to the polarity distribution of the Stanford magnetic field observations during 1975-1999. The index of activity of the large-scale magnetic field A(t), representing the sum of the intensities of dipole and octupole components, is introduced. It is shown that the cycle of the large-scale magnetic field of the Sun precedes on the average by 5.5 years the sunspot activity cycle, W(t). This means that the weak large-scale magnetic fields of the Sun do not result from decay and diffusion of strong fields from active regions as it is supposed in all modern theories of the solar cycle. On the basis of the new data the intensity of the current solar cycle 23 is predicted and some aspects of the theory of the solar cycle are discussed. Title: Cyclic Variations of CME Velocity Authors: Ivanov, E. V.; Obridko, V. N. Bibcode: 2001SoPh..198..179I Altcode: The semiannual mean CME velocities for the time interval of 1979-1989 have been analyzed to reveal a complex cyclic variation with a peak at the solar cycle maximum and a secondary peak at the minimum of the cycle. The growth of the mean CME width is accompanied by a growth of the mean CME velocity. It is shown that the cyclic variations of the mean CME velocity and the mean CME width are associated with the cyclic variations of the large-scale magnetic field structure and that the secondary peak of the semiannual mean CME velocity in 1985-1986 is due to a significant contribution of fast CMEs with a width of ∼100° at the minimum of the cycle. This peak is supposed to be due to the increasing role of the global large-scale magnetic field system with a characteristic size of cells of ∼ 70°-100° at the minimum of the cycle and the respective particularities of the large-scale magnetic field configuration in the corona. Title: Variations of the Solar-Wind Stream Structure in the Region of Subsonic Flow during the 11-Year Solar Cycle Authors: Lotova, N. A.; Obridko, V. N.; Vladimirskiĭ, K. V. Bibcode: 2000ARep...44..765L Altcode: The large-scale stream structure of the solar wind near the Sun and its evolution during the 11-year solar activity cycle are investigated. The study is based on observations of scattering of the radiation from compact natural radio sources at radial distances R≤14R S (R S is the solar radius). Regular observations were conducted in 1981 1998 on the RT-22 and DKR-1000 radio telescopes of the Russian Academy of Sciences at Pushchino, at λ=1.35 cm and 2.7 m, respectively. The radial dependences of the interplanetary scintillations m(R) and the scattering angle 2ϑ(R) are considered together with the structure of large-scale magnetic fields in the solar corona at R=2.5R S. The entire range of variations in the level of scattering and the associated heliolatitude flow structures in the subsonic solar wind forms over the 11-year solar cycle, as a direct result of the large-scale structure of the evolving magnetic fields at the source of the solar-wind streamlines. Title: Seasonal Variations in Solar High-Energy Neutrino Flux and Their Probable Source Authors: Rivin, Yu. R.; Obridko, V. N. Bibcode: 2000SoSyR..34..501R Altcode: 2000AVest..34..501R Cyclic variations of the solar neutrino flux (Homestake detector data) have been analyzed both from season to season and within different seasons and were compared with the corresponding variations of the large-scale deep-layer solar magnetic field. The analysis revealed a seasonal variation of the flux in the last twenty years with extremes at equinox epochs. The mechanism of this variation can be due to the asymmetry in magnitudes or to the twisting of the large-scale magnetic fields in the southern and northern hemispheres of the Sun in the flux modulation region. Title: Penetration of Coronal Magnetic Fields into Solar-Wind Streams Authors: Lotova, N. A.; Obridko, V. N.; Vladimirskii, K. V.; Rushin, V. Bibcode: 2000AstL...26..539L Altcode: The formation of solar-wind stream structure is investigated. Characteristic features of the solar and coronal magnetic-field structure, morphological features of the white-light corona, and radio maps of the solar-wind transition (transonic) region are compared. The solar-wind stream structure is detected and studied by using radio maps of the transition region, the raggedness of its boundaries, and their deviation from spherical symmetry. The radio maps have been constructed from radioastronomical observations in 1995-1997. It is shown that the structural changes in the transition region largely follow the changes occurring in regions closer to the Sun, in the circumsolar magnetic-field structure, and in the solar-corona structure. The correlations between the magnetic-field strength in the solar corona and the location of the inner (nearest the Sun) boundary of the transition region are analyzed. The distinct anticorrelation between the coronal magnetic-field strength and the distance of the transition region from the Sun is a crucial argument for the penetration of solar magnetic fields into plasma streams far from the Sun. Title: Amplitude and period of the dynamo wave and prediction of the solar cycle Authors: Dmitrieva, Isabella V.; Kuzanyan, Kirill M.; Obridko, Vladimir N. Bibcode: 2000SoPh..195..209D Altcode: The relation of the solar cycle period and its amplitude is a complex problem as there is no direct correlation between these two quantities. Nevertheless, the period of the cycle is of important influence to the Earth's climate, which has been noted by many authors. The present authors make an attempt to analyse the solar indices data taking into account recent developments of the asymptotic theory of the solar dynamo. The use of the WKB method enables us to estimate the amplitude and the period of the cycle versus dynamo wave parameters in the framework of the nonlinear development of the one-dimensional Parker migratory dynamo. These estimates link the period T and the amplitude a with dynamo number D and thickness of the generation layer of the solar convective zone h. As previous authors, we have not revealed any considerable correlation between the above quantities calculated in the usual way. However, we have found some similar dependences with good confidence using running cycle periods. We have noticed statistically significant dependences between the Wolf numbers and the running period of the magnetic cycle, as well as between maximum sunspot number and duration of the phase of growth of each sunspot cycle. The latter one supports asymptotic estimates of the nonlinear dynamo wave suggested earlier. These dependences may be useful for understanding the mechanism of the solar dynamo wave and prediction of the average maximum amplitude of solar cycles. Besides that, we have noted that the maximum amplitude of the cycle and the temporal derivative of the monthly Wolf numbers at the very beginning of the phase of growth of the cycle have high correlation coefficient of order 0.95. The link between Wolf number data and their derivative taken with a time shift enabled us to predict the dynamics of the sunspot activity. For the current cycle 23 this yields Wolf numbers of order 107±7. Title: Three types of solar wind flow Authors: Lotova, N. A.; Obridko, V. N.; Vladimirskii, K. V. Bibcode: 2000A&A...357.1051L Altcode: The origin of the large-scale stream structure of the solar wind flow was studied using an experimental approach. Radio astronomy data obtained in 1997 were compared with SOHO optical observations of the solar corona and magnetic structures derived from the J.Wilcox Observatory Zeeman data. A correlative relation was obtained between the position of the transonic region of the solar wind and magnetic field strength at the solar corona level. This relation falls into three branches corresponding to three types of the magnetic field structure: an open type with the field lines going in the interplanetary space, closed loop-like type and intermediate type including both configurations of field lines. The high-speed streams originate above the open configurations, while closed and intermediate configurations produce low-speed solar wind. Title: Large-Scale Solar Magnetic Field: Latitudinal Dependence Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 2000ARep...44..262O Altcode: Large-scale solar magnetic fields in the latitude range 50° S 50° N are analyzed in detail for a long time interval (1915 1990). We are primarily concerned with the two types of large-scale fields forming the two-and four-sector patterns on the Sun. The rotation parameters of these structures are obtained for all latitudes considered. The contribution of the two-sector structure grows and that of the four-sector structure decreases toward high latitudes. The magnetic field is activated simultaneously over a wide latitude range. Since both magnetic-field systems exhibit quasi-rigid rotation, their current systems must either be concentrated in a narrow latitude range or be situated beneath the convection zone, where rotation is only weakly differential. A period of about three years is manifest in the difference between the rotation periods for the two types of magnetic field. Physically, this may imply that these oscillations are external with respect to any level, and there is some phase delay due to their propagation from one level to another. We can conclude with a fair degree of certainty that as the activity level rises, the rotation speed decreases, and vice versa. Title: The Large-Scale Magnetic Field on the Sun: The Equatorial Region Authors: Obridko, V. N.; Shel'Ting, B. D. Bibcode: 2000ARep...44..103O Altcode: The sector structure and variations in the large-scale magnetic field of the Sun are studied in detail using solar magnetic-field data taken over a long time interval (1915 1990). The two-sector and four-sector structures are independent entities (i.e., their cross correlation is very small), and they are manifest in different ways during the main phases of the 11-year cycle. The contribution of the two-sector structure increases toward the cycle minimum, whereas that of the four-sector structure is larger near the maximum. The magnetic-field sources determining the two-sector structure are localized near the bottom of the convection zone. The well-known 2 3-year quasi-periodic oscillations are primarily associated with the four-sector structure. The variations in the rotational characteristics of these structures have a period of 55 60 years. The results obtained are compared with the latest helioseismology data. Title: Coronal Holes (Recorded from 1943) - a Source of the Solar-Induced Terrestrial Responses? Authors: Sykora, J.; Badalyan, O. G.; Obridko, V. N. Bibcode: 2000ESASP.463...95S Altcode: 2000sctc.proc...95S No abstract at ADS Title: Experimental confirmations of bioeffective effect of magnetic storms. Authors: Dmitrieva, I. D.; Khabarova, O. V.; Obridko, V. N.; Ragulskaja, M. V.; Reznikov, A. E. Bibcode: 2000A&AT...19...67D Altcode: The results of experiments for the determination of the influence of geomagnetic field disturbances on a human organism are considered. We used the method of electropuncture diagnostics by R. Voll for this end. The method is based on measurements, of conductivity in acupuncture points and is convenient because it allows us to estimate deviations from the norm in the functioning of various organs in the same units. The local A-index is used as an indicator of geomagnetic field disturbance. The daily measurements of the group (27 persons) have shown the presence of a synchronous mass response of inspected people on magnetic storms. At first it is exhibited as a sharp (within 3-4 hours) increase of conductivity of all the acupuncture points from normal values, which corresponds to a maximum of adaptational capabilities of an organism; and then a long duration (about 4 day) decrease of conductivity that describes the depression of all organs and systems of an organism. The reaction of adaptation on three magnetic storms of identical intensity going with an interval per week was registered for half of the inspected people. It was found that the duration of the depression phase and the imbalance of an organism, intrinsic to this phase, depends extremely on the wholeness of the organism (that is on the power of ties between organs and coordination of their activity), but not on the type of disease. Title: Analyses and modelling of coronal holes observed by CORONAS-1. I. Morphology and magnetic field configuration Authors: Obridko, V.; Formichev, V.; Kharshiladze, A. F.; Zhitnik, I.; Slemzin, V.; Hathaway, D.; Wu, S. T. Bibcode: 2000A&AT...18..819O Altcode: Two low-latitude coronal holes observed by CORONAS-1 in April and June 1994 are analysed together with magnetic field measurements obtained from Wilcox and Kitt Peak Solar Observatories. To estimate the comparable temperature of these two coronal holes, the YOHKOH observations are also utilized. Using this information, we have constructed three-dimensional magnetic field lines to illustrate the geometrical configuration of these coronal holes. The calculated synoptic maps are used to determine the existence of closed and open field regions of the hole. Finally, we have correlated the characteristics of two coronal holes with the observed solar wind speed. We found that the brighter coronal hole has a high-speed solar wind, and the dimmer coronal hole has a low-speed solar wind. Title: Studies of the rotation periods of photospheric magnetic fields in the 20th-22nd solar cycles Authors: Anan'ev, I. V.; Obridko, V. N. Bibcode: 1999ARep...43..831A Altcode: No abstract at ADS Title: Velocity and Magnetic Field Structure in the Vicinity of Hα Filaments Authors: Ioshpa, B. A.; Obridko, V. N. Bibcode: 1999ESASP.448..497I Altcode: 1999mfsp.conf..497I; 1999ESPM....9..497I No abstract at ADS Title: Long-Term Radio Scintillation Variations in the Circumsolar Plasma Authors: Lotova, N. A.; Obridko, V. N.; Vladimirskii, K. V.; Bird, M. K.; Pätzold, M.; Sieber, W.; Güsten, R.; Korelov, O. A. Bibcode: 1999SoPh..189..387L Altcode: Long-term scintillation measurements of the solar wind formation zone at solar elongations ranging from 1°-8° (Sun impact parameters: 4-30 R) were recorded using the water maser source IRC-20431 at the wavelength λ=1.35 cm during its annual solar occultations in December 1981-1998. Dramatic changes in the spatial dependence of the scintillation index were recorded over the course of the 11-year solar cycle. Markedly diminished scattering, attributed to a pronounced heliolatitude effect, was observed at the closest solar approach distances in the years around solar activity minimum. From parallel investigations of the solar magnetic field structure it was determined that the field strength at the source of the solar wind streamlines is the governing factor for the solar wind acceleration process. Particularly apparent in the scintillation data during solar activity minimum is the increasing role of the polar coronal holes with their associated open magnetic field structure. The dependence of the solar scattering intensity on heliolatitude fades in the years of high solar activity as the level of scintillations increases at polar latitudes. Title: Relation between the green-line polarization of the solar corona and corona magnetic fields Authors: Badalyan, O. G.; Obridko, V. N.; Sykora, J. Bibcode: 1999ARep...43..767B Altcode: No abstract at ADS Title: Structure and magnetic field of the July 11, 1991 eclipse corona from the solar cycle viewpoint Authors: Sykora, J.; Badalyan, O. G.; Obridko, V. N.; Pinter, T. Bibcode: 1999CoSka..29...89S Altcode: A set of the white-light images was used to perform relative photometry of the July 11, 1991 eclipse corona. The observed global form of that day corona was found to be rather unusual for the actual solar cycle phase. In this relation, the recently calculated coronal magnetic field structures and strengths are presented and discussed. An idea on the close relation between the observed global form of the corona and the presence of the individual coronal structures around the solar limb, on the one hand, and the calculated magnetic field topology and strength, on the other hand, is supported and found to be of great interest. Title: Long-term variations of the solar-geomagnetic correlation, total solar irradiance, and northern hemispheric temperature (1868-1997) Authors: Kishcha, P. V.; Dmitrieva, I. V.; Obridko, V. N. Bibcode: 1999JASTP..61..799K Altcode: 1999JATP...61..799K Time series for annual means of sunspot numbers, aa-indices of geomagnetic activity and annual numbers of 3-h time intervals with different values of aa-indices (aa<=4 and aa>=30) from 1868 to 1997 have been examined by the method of running-window cross-correlation analysis. It has been found that the solar-geomagnetic correlation varies over time. In particular, long-term variations of the 23-year running correlation appear to have a quasi periodicity of about 40-50 years, superposed on a linear trend, where the trend describes a general decrease of the 23-year running-window correlation between 1868 and the present. Long-term variations of the solar-geomagnetic correlation may result from the quasi-periodic fluctuations of the time lag of geomagnetic indices relative to sunspot numbers, superposed on an upward linear trend of time lag. Secular variations of the northern hemisphere land-air surface temperature anomalies and two solar indices that are potential proxy measures for the total solar irradiance (i.e., the length of the sunspot cycle and the Hoyt and Schatten (Hoyt, D.V., Schatten, K.V., 1993. Journal of Physical Research 98, 18,895-18,906.) composite index) have been compared with the long-term variations of the solar-geomagnetic correlation. The extremum points (points where the derivative vanishes to zero) of these variations are found to occur contemporaneously during the periods of low solar-geomagnetic correlation, suggesting, perhaps, that the long-term variations of solar-geomagnetic correlation are due to some long-term processes on the Sun and that they have a measurable effect on the Earth. Title: North-South asymmetry of the magnitude of large-scale solar magnetic fields Authors: Rivin, Yu. R.; Obridko, V. N. Bibcode: 1999ARep...43..479R Altcode: An annual variation with its extrema at the equinoxes has been detected in photospheric measurements of the magnitude of the large-scale solar magnetic field near the equator. It is proposed that a hemispheric asymmetry in the magnitudes of the large-scale magnetic fields in the region of generation of the quadrupole field is responsible for this variation. Title: Structure and Cyclic Variations of Open Magnetic Fields in the sun Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1999SoPh..187..185O Altcode: The structure and variations of open field regions (OFRs) are analyzed against the solar cycle for the time interval of 1970-1996. The cycle of the large-scale magnetic field (LSMF) begins in the vicinity of maximum Wolf numbers, i.e. during the polar field reversal. At the beginning of the LSMF cycle, the polar and mid-latitude magnetic field systems are connected by a narrow bridge, but later they evolve independently. The polar field at the latitudes above 60° has a completely open configuration and fills the whole area of the polar caps near the cycle minimum of local fields. At this time, essentially all of the open solar flux is from the polar caps. The mid-latitude open field regions (OFRs) occur at a latitude of 30-40° away from solar minimum and drift slowly towards the equator to form a typical 'butterfly diagram' at the periphery of the local field zone. This supports the concept of a single complex - 'large-scale magnetic field - active region - coronal hole'. The rotation characteristics of OFRs have been analyzed to reveal a near solid-body rotation, much more rigid than in the case of sunspots. The rotation characteristics are shown to depend on the phase of the solar cycle. Title: Phenomenology of coronal mass ejections Authors: Mogilevsky, E. I.; Obridko, V. N.; Shilova, N. S. Bibcode: 1999ARep...43..255M Altcode: An attempt to describe the phenomenology of solar coronal mass ejections (CMEs) at all wavelength bands is undertaken. The development of several typical CMEs in 1996 and 1997 is considered in detail. Among the properties revealed, we especially emphasize (1) the presence of initial eruption prominences that are relatively distant from each other, (2) the development of CMEs from two eruption sites, and (3) the connection of CMEs with structural evolution, i.e., large-scale solar-activity complexes. In addition to determining the basic properties of CMEs, we compare scenarios for CMEs and flares and search for common features in the natures of these phenomena, which have very different temporal and spatial scales. A qualitative model for the above phenomena is put forward. Title: Time variations of solar neutrino. The main arguments pro and some inferences Authors: Rivin, Yu. R.; Obridko, V. N. Bibcode: 1999astro.ph..2074R Altcode: The paper contains some arguments in support of time variations of the high-speed flux of solar neutrino Title: Relevance of CME to the Structure of Large-Scale Solar Magnetic Fields Authors: Ivanov, E. V.; Obridko, V. N.; Nepomnyashchaya, E. V.; Kutilina, N. V. Bibcode: 1999SoPh..184..369I Altcode: The relevance of the occurrence rate and location of CME events to two main systems (giant and supergiant) of the large-scale solar magnetic field structure has been investigated. The clustering of CME events and solar flares toward the neutral line of the global field system (neutral line of the source surface field) corroborates the finding by Hundhausen that CME locations track the heliomagnetic equator. A good correlation has been revealed between the CME occurrence rate and variations of the index of the effective solar multipole, that characterizes the typical scale of the global solar magnetic field. The CME rate exhibits sharp jumps/decreases when the index of the effective solar multipole passes through n=4. The observations of X-ray 'blow-out' effects have been analyzed as probable manifestations of CMEs on the disk and have been compared with the large-scale magnetic field structure. As shown by the analysis, the X-ray arcades straddle the neutral line and occur, or at least tend to occur, where the neutral line exhibits a sharp bend. A conclusion is made that CME events are caused by interaction of two large-scale field systems, one of them (the global field system) determining the location of CMEs and another (the system of closed magnetic fields) their occurrence rate. Title: Structure of the Heliospheric Current Sheet derived for the interval 1915 -1916 Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1999SoPh..184..187O Altcode: Hα observations of solar large-scale fields were used to reconstruct the heliosphere structure for the time interval of 1915-1996. A special method of polar correction was developed. The expansion coefficients in Legendre polynomials were calculated. An atlas of the heliosphere structure was compiled. `Inferred' strength of the polar and equatorial field in 1915-1996 years was calculated. Cyclic variations of the polar field and the number of polar plages were compared to show a satisfactory agreement. The q parameter, characterizing the divergence of the polar plumes in the epochs of the solar minimum, was calculated and its quasi-periodic behaviour with a period of the order of 70 years was revealed. Our calculations were tentatively compared with the interplanetary magnetic field structure. Title: Relationship between the green-line corona polarization and coronal magnetic fields Authors: Badalyan, O. G.; Obridko, V. N.; Sýkora, J. Bibcode: 1999ASSL..243..373B Altcode: 1999sopo.conf..373B No abstract at ADS Title: Variations of the total solar radiation flux and magnetic field with 2 to 10-day periods Authors: Obridko, V. N.; Anan'ev, I. V.; Arlt, K.; Pflug, K. Bibcode: 1998ARep...42..534O Altcode: A joint spectral analysis of cyclic variations of the total solar radiation flux and magnetic field is presented. In the period range from 2-10 days, the solar-constant and magnetic-field spectra are determined not only by harmonics of the solar rotation, but also by the structure of active regions and the lifetime and variation time scales for magnetic fields on various scales. Up to a period of nine days, all harmonics have a rotational nature. Beginning from a period of seven days, the spectra are determined by variations of the solar activity. Title: Effects of the solar magnetic field on the solar wind stream structure Authors: Lotova, N. A.; Obridko, V. N.; Vladimirsky, K. V. Bibcode: 1998ARep...42..553L Altcode: We carry out a comprehensive analysis of experimental data on the solar surface magnetic field and the scattering properties of the circumsolar plasma in the subsonic region at R ~= (4-12) R_solar to study the forma- tion mechanism of the solar wind stream structure. We use the data on the radial dependence of the scattering angle of radio waves obtained in 1985-1996 during radio occultation experiments in the circumsolar plasma with the source 3C 144. These data are compared with the helio-latitude structure of the solar surface magnetic field. We have established that the typical deviations of the relation between the scattering and the radial distance from a regular power law and the decrease in scattering at small distances from the Sun correlate with the open structure of magnetic field lines and with the penetration of the fields from coronal holes and other local sources in the plasma streams. Title: Natural Disasters and Solar Activity (Based on Chronicles and Annals) Authors: Dmitrieva, I. V.; Zaborova, E. P.; Obridko, V. N. Bibcode: 1998A&AT...17...29D Altcode: The chronicle data on natural phenomena observed in Europe and in Russia from the year 0 to 1600 were analysed. We compared droughts, cold-spells, epidemics, epizootics and famines with solar activity data (sunspots visible to the naked eye). As shown by the analysis, the maximum occurrence of droughts, epidemics and epizootics either coincides with the sunspot maximum or is observed in the growth phase of solar activity. For very cold winters the correlation with solar activity was not so pronounced. As to famines, they do not reveal noticeable correlation with any natural factors. Title: White-light polar plumes from three 'minimum-like' solar eclipses Authors: Sykora, J.; Ambrovz, P.; Minarovjech, M.; Obridko, V. N.; Pinter, Th.; Rybansky, M. Bibcode: 1998ESASP.421...79S Altcode: 1998sjcp.conf...79S No abstract at ADS Title: Evolution of the Filament/CH/Magnetic Field Complex Authors: Ioshpa, B. A.; Mogilevsky, E. I.; Obridko, V. N. Bibcode: 1998ASPC..150..393I Altcode: 1998npsp.conf..393I; 1998IAUCo.167..393I No abstract at ADS Title: Some Investigations of Coronal Holes and Large-scale Solar Magnetic Fields Using Coronas, Yohkoh, SOHO and Ground-based Data (invited) Authors: Obridko, Vladimir N. Bibcode: 1998asct.conf...41O Altcode: No abstract at ADS Title: Analyses and Modeling of Coronal Holes Observed by Coronas-I: II. MHD Simulation Authors: Wang, A. H.; Wu, S. T.; Dryer, M.; Hathaway, D.; Obridko, V.; Fomichev, V.; Kharshiladze, A. F.; Zhitnik, L.; Slemzin, V. Bibcode: 1998asct.conf..273W Altcode: No abstract at ADS Title: Variations of Solar Irradiance, 10.7 CM Radio Flux, He I 10830 Angstroms Equivalent Width and Global Magnetic Field Intensity and Their Relation to Large-Scale Solar Magnetic Field Structure Authors: Ivanov, E. V.; Obridko, V. N.; Ananyev, I. V. Bibcode: 1998SoPh..177..217I Altcode: Variations of total solar irradiance, 10.7 cm radio emission, the Hei 10830 Ú equivalent width and the solar magnetic field flux measured for the entire Sun are compared with variations of the energy index of the global solar magnetic field and the index of the effective solar multipole for years 1979-1992. It is shown that photospheric radiation and that generated in the upper chromosphere and corona display different relationships with the global magnetic field of the Sun, and that interaction between the magnetic field and the solar irradiance is much more complicated than the traditional blocking effect. Title: Solar activity-climate coupling and atmospheric circulation Authors: Dmitrieva, I. V.; Zaborova, R. P.; Obridko, V. N. Bibcode: 1998A&AT...16..133D Altcode: Long series of various climate parameters and their relation to solar activity have been analysed. A sudden variation in the character of the solar activity-climate coupling has been revealed during the change of the global circulation epochs in the North hemisphere. Title: Cyclic Variation of the Solar Wind Velocity and Energy of the Large-Scale Magnetic Field of the Sun Authors: Shelting, Bertha D.; Obridko, Vladimir N. Bibcode: 1998asct.conf..447S Altcode: No abstract at ADS Title: Variations of Solar Irradiance, 10.7 CM Radio Flux, He I 10830 Å Equivalent Width and Global Magnetic Field Intensity and their Relation to Large-Scale Solar Magnetic Field Structure Authors: Ivanov, E. V.; Obridko, V. N.; Ananyev, I. V. Bibcode: 1998sers.conf..217I Altcode: No abstract at ADS Title: Relation of the CME Rate to the Large-scale Solar Magnetic Fields Structure Authors: Ivanov, Evgeny V.; Obridko, Vladimir N.; Shelting, Bertha D. Bibcode: 1998asct.conf..365I Altcode: No abstract at ADS Title: Structure and Cyclic Variations of Open Magnetic Fields in the Sun Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1997ESASP.415..357O Altcode: 1997cpsh.conf..357O No abstract at ADS Title: International Solar Cycle Studies - ISCS (1998-2002) Authors: Obridko, V. N. Bibcode: 1997ESASP.415..267O Altcode: 1997cpsh.conf..267O No abstract at ADS Title: Large-Scale Magnetic Field Structures and Coronal Holes on the Sun Authors: Mogilevsky, E. I.; Obridko, V. N.; Shilova, N. S. Bibcode: 1997SoPh..176..107M Altcode: This paper is aimed at establishing the relationship between the large-scale magnetic fields (LSMF), coronal holes (CH), and active regions (AR) in the Sun. The LSMF structure was analyzed by calculating the vector photospheric magnetic field under a potential approximation. Synoptic maps were drawn to study the distribution of the B field component and to isolate regions where the open field lines of the unipolar magnetic field are most radial. These are the sites of occurrence of X-ray and Hei 10830 Å coronal holes detected from the SXT/Yohkoh images. It is shown that coronal holes are usually located in LSMF regions with a typical pattern of divergentB vectors and a so-called `saddle' configuration.B vectors from the `conjugate' (spaced by 90°) coronal holes converge towards the active regions between CH. Variations in AR distort coronal holes and change their boundaries. This implies that the energy regime in CH depends on the energy supply from the active region. The LSMF structure is more stable than coronal holes, remaining practically unchanged during tens of rotations of the Sun. Thus, a peculiar magnetically coupled system of LSMF/CH/AR has been revealed. A model has been suggested to describe the interaction of the emerging toroids in the convection zone and in the photosphere. The cellular convection, that develops at the center of the toroids, is responsible for the occurrence of active regions. The model qualitatively describes the observed particularities of the LSMF/CH/AR system. Title: Dependence of the Density of the Upper Atmosphere on Solar Activity from Satellite Drag Data Authors: Shubin, V. N.; Deminov, M. G.; Nepomnyashchaya, E. V.; Obridko, V. N.; Shelting, B. D.; Chizhenkov, V. A. Bibcode: 1997CosRe..35..114S Altcode: No abstract at ADS Title: Large-scale structure of solar magnetic fields and coronal mass ejections Authors: Ivanov, E. V.; Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1997ARep...41..236I Altcode: No abstract at ADS Title: Relation between DIFOS "irradiance" data and solar activity. Authors: Pflug, K.; Obridko, V. N.; Arlt, K.; Lebedev, N. I. Bibcode: 1997A&A...317..925P Altcode: Solar irradiance measurements with the DIFOS-photometer aboard the satellite CORONAS-I were compared with short term variations of solar activity. The sunspot blocking effect was confirmed and an anticorrelation with the 2600 MHz radio flux is very pronounced. Furthermore a close relation to the large scale structure of the magnetic field existed during the observational period from 1994, March 16 to May 7. Title: Cyclic variation of the high-energy solar neutrino flux Authors: Rivin, Yu. R.; Obridko, V. N. Bibcode: 1997ARep...41...76R Altcode: No abstract at ADS Title: Evolution of the Filament/CH/ Magnetic Field Complex Authors: Ioshpa, B. A.; Mogilevskij, E. I.; Obridko, V. N. Bibcode: 1997jena.confE..41I Altcode: The SOHO and Yohkoh images, as well as the H-alpha filtergrams and magnetograms from IZMIRAN have been used to analyze the evolution of the complex of related phenomena - filament, active region, and accompanying pair of coronal holes - during two solar rotations in August-September, 1996. The whole complex has been considered against the large-scale magnetic field, calculated under potential approximation. Peculiar points have been isolated along the changing filament. It is shown that the phenomena under investigation (filament, active region, and coronal hole) form a single complex, connected with the magnetic field structure. Title: The magnetic field in the near-equatorial zone of the solar photosphere Authors: Obridko, V. N.; Rivin, Yu. R. Bibcode: 1996ARep...40..740O Altcode: No abstract at ADS Title: Forecasting the time series of Wolf numbers for the 23rd solar cycle Authors: Bondar', T. N.; Rotanova, N. M.; Obridko, V. N. Bibcode: 1996AstL...22..562B Altcode: 1996PAZh...22..628B No abstract at ADS Title: The role of solar magnetic field in the neutrino flux modulation. Authors: Obridko, V. N.; Rivin, Y. R. Bibcode: 1996A&A...308..951O Altcode: The flux of solar neutrino coming to the Earth is shown to be modulated by the magnetic field on its propagation route. This explains the 11-year periodicity in the neutrino flux variation. Quasi-biennial variations of the flux are claimed to have a different origin, i.e. to be due to processes in the solar interior. Various indices used to describe solar magnetic field variations are discussed, as well as some implications of the obtained results. Title: Fourier Parameters and Moments of Polarization Profiles of Magnetically Active Lines. Fourier Vector Magnetograph Authors: Ioshpa, B.; Obridko, V.; Kozhevatov, I. Bibcode: 1996SoPh..164..373I Altcode: A new method is proposed to determine all components of the solar magnetic fields using the cumulants of the profile of a magnetic sensitive line. The method is based on polarization measurements in a number of points of the line profile and subsequent calculation of the amplitudes and phases of its two first Fourier-harmonics. Title: Is Our Knowledge of Solar Indices Enough to Explain Satellite Drag? Authors: Deminov, M. G.; Nepomnyashchaya, E. V.; Obridko, V. N.; Shelting, D. B.; Shubin, V. N.; Chizhenkov, V. A. Bibcode: 1996ASPC...95..421D Altcode: 1996sdit.conf..421D No abstract at ADS Title: Calculating Solar Wind Parameters from Solar Magnetic Field Data Authors: Obridko, V. N.; Kharshiladze, A. F.; Shelting, D. B. Bibcode: 1996ASPC...95..366O Altcode: 1996sdit.conf..366O No abstract at ADS Title: What Are the Solar Drivers Responsible for Helio-Meteorological Effects? Authors: Dmitrieva, I. V.; Obridko, V. N.; Zaborova, E. P. Bibcode: 1996ASPC...95..497D Altcode: 1996sdit.conf..497D No abstract at ADS Title: On calculating the solar wind parameters from the solar magnetic field data Authors: Obridko, V. N.; Kharshiladze, A. F.; Shelting, B. D. Bibcode: 1996A&AT...11...65O Altcode: It is shown that the expansion factor of the solar magnetic field is insufficient to calculate the solar wind velocity. Moreover, the magnetic field structure cannot unambiguously determine the solar wind velocity field in therms of the source surface concept and the potential magnetic field approximation in the corona. It is shown that characteristics relating the solar and near-Earth interplanetary magnetic field undergo cyclic variations. Title: Some aspects of heliometeorologic coupling Authors: Obridko, V. N.; Oraevsky, V. N.; Dmitrieva, I. V.; Zaborova, E. P. Bibcode: 1996A&AT....9..149O Altcode: Solar activity events that influence the lower atmosphere of the Earth have been considered as a function of various geographical factors. Certain regions have been isolated, where meteorologic characteristics are closely related to solar activity. The summer duration in one of these regions is shown to correlate well with solar activity characteristics, such as the Wolf number and the geomagnetic aa-index. A hypothesis is suggested that there are certain zones through which solar activity controls the entire Earth's atmosphere. The ways to locate such zones are discussed. Title: Global magnetic studies of the sun - Properties of the polar and equatorial fields Authors: Ermakov, F. A.; Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1995AZh....72..753E Altcode: The odd-zone potential of the induction field B at the poles and equator is considered. Extrema of the components Br and Bv fall in phase minima and maxima, respectively, with the anomalous (non-dipole) part substantially exceeding the normal (dipole) part. Behavior of the empirical observational parameter q supports this fact for the poles. Title: Global magnetic studies of the Sun: Properties of the polar and equatorial fields Authors: Ermakov, F. A.; Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1995ARep...39..672E Altcode: No abstract at ADS Title: The index of recurrence of planetary geomagnetic activity and its connection with the solar cycle. Authors: Levitin, A. E.; Obridko, V. N.; Val'Chuk, T. E.; Golyshev, S. A.; Dremukhina, L. A. Bibcode: 1995Ge&Ae..35..137L Altcode: No abstract at ADS Title: Solar Magnetic Field Modulation of the Neutrino Flux Authors: Obridko, V. N.; Rivin, Yu. R. Bibcode: 1995IBVS.4160....1O Altcode: No abstract at ADS Title: Some Comments on the Problem of Solar Cycle Prediction Authors: Obridko, V. N. Bibcode: 1995SoPh..156..179O Altcode: The paper provides a number of regression equations that can be used to calculate the height of the odd Wolf number cycle. The feasibility of the rule of Gnevyshev-Ohl is analyzed as applied to the geomagneticaa-index. A modified rule of Gnevyshev-Ohl has been formulated to describe the behaviour ofaa-indices. A new method is suggested for early prediction of the next solar cycle. In this method, the angular coefficient (straightline slope) of linear dependence ofaa-indices on the Wolf number at the descending branch of the cycle has been used as a prediction index. It is shown to a high degree of certainty that the new prediction index is related to the height of the forthcoming cycle. While the methods based on the ratio of the even-odd cycles in a pair give very high values of cycle 23 maximum (203.2 ± 10.7), our new index, on the contrary, gives very low values (74.7 ± 6.9). There are some contradictory symptoms indicating that the forthcoming cycle 23 is likely to violate the regularities established for the past 125 years. Title: Stochastic autoregression modeling and forecasting of the Wolf-number time series Authors: Bondar', T. N.; Rotanova, N. M.; Obridko, V. N. Bibcode: 1995ARep...39..115B Altcode: No abstract at ADS Title: On the confidence level of the correlation between the divergence factor of the lines of force on the sun and the solar-wind velocity Authors: Obridko, V. N.; Kharshiladze, A. F.; Shel'Ting, B. D. Bibcode: 1995ARep...39...95O Altcode: No abstract at ADS Title: Global magnetology of the sun: Complementary fluxes and the natural scale of cycles Authors: Ermakov, F. A.; Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1995ARep...39...86E Altcode: No abstract at ADS Title: Neutrino flux variations and solar magnetic fields. Authors: Obridko, V. N.; Rivin, Yu. R. Bibcode: 1995BRASP..59.1562O Altcode: It is shown that the neutrino flux emerging from the solar core is modulated by a magnetic field, conditioning an 11-year cyclicity of the flux. A quasi-two-year flux variation is related to another source, i.e., the core processes. Various indices are considered to describe heliomagnetic field variations as well as some consequences of this consideration. Title: Cyclic variations of large-scale solar magnetic fields Authors: Obridko, V. N. Bibcode: 1995BCrAO..92...67O Altcode: No abstract at ADS Title: International Decade of Solar Cycle Studies (IDSCS) Authors: Obridko, V. N.; Oraevsky, V. N.; Allen, J. H. Bibcode: 1994step.conf..557O Altcode: No abstract at ADS Title: Results of the Russian FLARES 22 Campaign Authors: Obridko, V. N.; Ishkov, V. N. Bibcode: 1994step.conf...57O Altcode: No abstract at ADS Title: International studies of solar activity. Authors: Obridko, V. N.; Oraevskij, V. N. Bibcode: 1993ZemVs...5...12O Altcode: No abstract at ADS Title: Simulation of the Chain "Solar Activity-Weather-Ecology" Authors: Obridko, V.; Dmitrieva, I.; Zaborova, E. Bibcode: 1993stp1.conf..243O Altcode: No abstract at ADS Title: The Main Features of Solar Cycle 22 and Some Forecasts of Cycle 23 Authors: Obridko, V.; Belov, A.; Ishkov, V.; Rivin, Y.; Kuklin, G.; Vitinsky, Y. Bibcode: 1993stp2.conf..261O Altcode: No abstract at ADS Title: Solar Cycle-Predictions Based on Solar Cycles Phases Authors: Obridko, V.; Kuklin, G. Bibcode: 1993stp2.conf..273O Altcode: No abstract at ADS Title: Frequency Composition of Multiyear Variations of the Magnetic Field of the Sun as a Whole Authors: Rivin, Y. R.; Obridko, V. N. Bibcode: 1992SvA....36..557R Altcode: No abstract at ADS Title: Frequency composition of long-period magnetic field variations of the sun as a star Authors: Rivin, Yu. R.; Obridko, V. N. Bibcode: 1992AZh....69.1083R Altcode: The frequency composition of the general magnetic field of the sun as a star is determined on the basis of Stanford observations, as well as linear and square-law detection of the field during the period June 1975-December 1990. Four groups of significant harmonics are identified: long-period (greater than about 1 yr), and 27-, 13-, and 9-d variations. A detailed analysis of the spectrum of diurnal values of B(s), B(s)-parallel, and B(s)-squared, as well as of their semiannual mean values and dispersions reveals a complex structure of long-period B(s) variations (about 20-, 6-, 2-, and 1-yr variations). The agreement of frequency characteristics of long-period B(s) variations with those of the interplanetary magnetic field is discussed. The cause of the 11-yr cyclicity appearing in the detected B(s) values is analyzed. Title: Cyclic Variation of the Global Magnetic Field Indices Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1992SoPh..137..167O Altcode: The energetical aspect of solar phenomena of different spatial and time scales has been studied with special attention to global magnetic fields. Cyclic regularities in the heliosphere are determined by energetics of global magnetic fields. The energy variation of global fields consists of a number of maxima and minima coinciding with reference points of the sunspot cycle. The correlations of a number of well-known indices in the heliosphere with Wolf numbers and with indices of energetics of the global magnetic field have been investigated. The results can be used to identify more exactly the reference points of the cycle. Title: Some Comments to the Problem of Extended Cycles in Large-Scale Magnetic Fields Authors: Obridko, Vladimir; Gaziev, Gulu Bibcode: 1992ASPC...27..410O Altcode: 1992socy.work..410O No abstract at ADS Title: Coronal holes and photospheric magnetic fields Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1990AZh....67..890O Altcode: Magnetic field observations reported by Hoeksema and Scherrer (1986) were used to examine the mutual arrangement of coronal holes recorded in the 10830 He I line during the fall-off phase (1982-1985) of the 21st solar cycle, relative to the large-scale photospheric and coronal magnetic fields. Results show that the coronal holes change in phase with the total solar radiation flux in the Ca II line, indicating their common nature. A mechanism for heating coronal holes, similar to that proposed by Pikel'ner (1960), is discussed. Title: Some problems of investigation of the Sun within the STEP program. Authors: Kuklin, G. V.; Obridko, V. N. Bibcode: 1990Ge&Ae..30..529K Altcode: The basic objectives of solar investigations in the framework of the Solar-Terrestrial Energy Progam (STEP) are examined. Particular attention is given to energy transfer from the inner layers outward to the corona and heliosphere. Also considered are the generation of magnetic fields and helioseismological methods for investigating the inner structure of the sun. The interaction between local and global fields is considered. Title: Coronal Holes and Photospheric Magnetic Fields Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1990SvA....34..449O Altcode: No abstract at ADS Title: Some problems of the investigation of the Sun within the framework of the STEP project. Authors: Kuklin, G. V.; Obridko, V. N. Bibcode: 1990Ge&Ae..30..449K Altcode: The main problems of investigation of the Sun within the framework of the international program Energy in the Sun-Earth System (STEP) are formulated. The problems of energy transport from the inner layers outwards right to the corona and heliosphere are discussed. The problems of generation of magnetic fields and helioseismological methods of studying the inner structure of the Sun are discussed. Special attention is devoted to the interrelation of local and global fields. Title: Fine Structure of the Solar Cycle Authors: Shelting, B. D.; Obridko, V. N.; Yermakov, F. A. Bibcode: 1989ATsir1540...23S Altcode: No abstract at ADS Title: SOLAR-CYCLE-21 in Heliomagnetic Indices Authors: Obridko, V. N.; Yermakov, F. A. Bibcode: 1989ATsir1539...24O Altcode: No abstract at ADS Title: Coronal holes as indicators of large-scale magnetic fields in the corona Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1989SoPh..124...73O Altcode: It is shown that coronal holes may be used as indicators to trace the location of the neutral line on the source surface in the corona. At the same time, coronal holes are shown to concentrate in regions of enhanced magnetic field at the source surface. This provides us with a simple method for predicting the interplanetary current sheet and sector structure which, in turn, determine the location of the proton complexes and the outflow regions of high-velocity streams. Rotation of coronal holes has been studied. Rather than being rigid, it displays the same reduced differentiallity as the rest of the corona. However, there are particular periods 2 or 3 years before the cycle minimum when the solid-body type of rotation is settled for both the coronal holes and the corona as a whole. Title: The Spacetime Polarity Distribution of the Largescale Solar Magnetic Field Authors: Obridko, V. N.; Makarov, V. I.; Tavastsherna, K. S.; Gaziev, G. A. Bibcode: 1989ATsir1536...31O Altcode: No abstract at ADS Title: The Sun as a Source of Energy and Mass Authors: Kuklin, G. V.; Obridko, V. N. Bibcode: 1989step.conf....7K Altcode: No abstract at ADS Title: Solar/terrestrial physics Authors: Ivanov-Kholodnyi, G. S.; Lotova, N. A.; Obridko, V. N.; Fel'Dshtein, Ia. I.; Fomichev, V. V. Bibcode: 1989epps.book...36I Altcode: The history of the development of solar/terrestrial physics research at IZMIRAN (the Soviet Institute for the Study of Terrestrial Magnetism, the Ionosphere, and the Propagation of Radio Waves) is reviewed, and the activity of the Institute in organizing international solar/terrestrial physics research is examined. Particular attention is given to investigations of solar corpuscular radiation and its effect on the ionosphere; and to studies of auroras and the interplanetary medium. Title: Dispersion of monthly mean Wolf's numbers as a prediction index. Authors: Obridko, V. N. Bibcode: 1989BSolD..11..106O Altcode: It is shown that at the decreasing branch of the cycle the r.m.s. deviation of monthly mean Wolf's numbers from their smoothed values correlates with the height of the next maximum (the correlation coefficient is 0.649). This gives predicted W22 = 138±20.9. Title: Book Review: The solar wind and the earth. / Reidel, 1987 Authors: Obridko, V.; Obridko, V. Bibcode: 1988SoPh..116..409O Altcode: 1988SoPh..116..409A No abstract at ADS Title: Coronal holes and prediction of recurrent high-velocity streams. Authors: Shel'Ting, B. D.; Obridko, V. N. Bibcode: 1988KFNT....4...29S Altcode: Data for 1973 - 1979 have been used to study the relationships between the large-scale solar magnetic field, coronal holes, the IMF sector structure and high-velocity streams by applying the cross-correlation analysis and direct comparison. Remarkably high time and space correlations have been obtained. Title: Book-Review - Solar Maximum Analysis - Proceedings International Workshop - Irkutsk U.S.S.R. - 1985JUN17-24 Authors: Stepanov, V. E.; Obridko, V. N. Bibcode: 1988S&T....75R.498S Altcode: No abstract at ADS Title: A two-component working model for the atmosphere of a large sunspot umbra Authors: Obridko, V. N.; Staude, J. Bibcode: 1988A&A...189..232O Altcode: A two-component working model for the atmosphere of the umbra of a typical large sunspot is proposed which represents an improvement over the earlier Wroclaw-Ondrejov sunspot model. The main component is assumed to consist of cold matter at photospheric levels, a thin chromosphere, a shallow transition region, and a deep-set corona. The secondary component in the model has a volume filling factor of 5-10 percent at all heights and is suggested to consist of thin fine-structure elements which are elongated parallel to the magnetic field. The present model is able to account for the basic features of sunspot observations at frequencies from X-rays up to microwaves. Title: Differential rotation of the sun Authors: Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1988IGAFS..83....3O Altcode: Recent results on the differential rotation of the sun are reviewed. It is shown that the concept of the differential rotation of tracers is supported by a large body of observational evidence; most of the tracers display maximum equatorial velocity at the end of a cycle and an abrupt decrease of differentiality several years prior to that. A number of sharp narrow peaks have been revealed in the frequency spectrum, suggesting the existence of separate (perhaps rigid-body) modes with synodic periods of 27.2 and 28.4 days. Title: On the differential rotation of coronal holes. Authors: Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1988BSolD1988...89O Altcode: It is shown that the differential character of rotation of coronal holes is weakly pronounced (B ≡ 0.4) only near the solar minimum, i.e., in the period when the green corona also rotates rigidly. In other periods, coronal holes as well as the entire corona display a noticeable differential rotation (B ⪆ 1.0). Title: Rotation of the sector structure of the interplanetary magnetic field(1926 - 1980). Authors: Kuklin, G. V.; Obridko, V. N. Bibcode: 1988BSolD1988...78K Altcode: Dynamics of the rotation of the interplanetary magnetic field sector structure is analysed for 1926 - 1980. Discrete rotation periods, coexistence of not more than two rotation systems, presence of acceleration and deceleration of rotation, influence of the places and parity of the 11 year solar cycle and phases of the secular cycle are detected. Some peculiarities of rotation are suspected to be due to the presence of zonal winds in the solar corona, influencing the outflowing magnetic field. Title: Prognozirovanie ionosfernykh, magnitosfernykh vozmushchenij i solnechnoj aktivnosti (Prediction of ionospheric, magnetospheric disturbances and of solar activity). Authors: Zevakina, R. A.; Obridko, V. N. Bibcode: 1988pimv.book.....Z Altcode: No abstract at ADS Title: Reciprocal space-time localization of the sector structure of the interplanetary magnetic field and the large-scale field of the Sun. Authors: Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1987Ge&Ae..27..660O Altcode: The statistical correlation between the large-scale solar magnetic field and the IMF sector structure is examined. It is shown that, despite a close interrelationship, there can be slight divergences between the two, connected with the inadequacy of their determination and the presence of short-term perturbations. A refined determination is made of the boundary-zone width between the beginning of the coronal hole and the boundary of the large-scale solar magnetic field; a value of 40-50 heliographic degrees is obtained. Title: Energetics of activity of flare stars and the Sun: a synergetical approach. Authors: Gershberg, R. E.; Mogilevskii, E. I.; Obridko, V. N. Bibcode: 1987KFNT....3R...3G Altcode: 1987KNFT....3R...3G; 1987KFNT....3e...3G The analysis of the energy spectra of flares on flare stars and on the Sun shows that the maximum energy of optical radiation of stellar flares is close to 1029J and of solar flares is several units of 1025J; taken into account the electromagnetic emission in other wavelength ranges, losses on particle acceleration and hydrodynamic losses, it is concluded that the total energy released in such flares must exceed the above estimates by an order of magnitude. Difficulties of the standard model of current sheets in providing a high energy release in powerful solar and stellar flares are discussed and the necessity of a synergetical approach to analyse structural and kinematic properties of convective zones in the stars with a magnetic field is substantiated. The model of soliton gas as a mechanism of rapid transport of large portions of magnetic energy from deep convection layers into the atmosphere is suggested and discussed in brief. This mechanism seems to be able to provide the energetics of the most powerful solar and stellar flares. Title: Relationship between coronal holes, high-velocity streams and the sector structure of the interplanetary magnetic field. Authors: Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1987Ge&Ae..27..197O Altcode: A statistical analysis of a large volume of data shows that most high-speed streams of the solar wind are generated right after passage through the sector structure (SS) of the IMF and just before passage through the coronal-hole (CH) boundary. About 74 to 87 percent of the CH is located within sectors of the same polarity, and the width of the boundary zone between the SS and CH commencement amounts to 20-40 heliographic degrees. About 38-57 percent of all high-speed streams connected with CHs commence in this zone. Title: Solar Maximum Analysis. Proceedings of the International Workshop, held in Irkutsk, USSR, June 17-24, 1985. Authors: Stepanov, V. E.; Obridko, V. N. Bibcode: 1987sman.work.....S Altcode: No abstract at ADS Title: Prediction of ionospheric and magnetospheric disturbances and solar activity Authors: Zevakina, R. A.; Obridko, V. N. Bibcode: 1987pimd.conf.....Z Altcode: Papers are presented on such topics as the short-term forecasting of solar activity, the use of radio emission for the diagnostics of proton flares and geoefficient phenomena on the sun, the geomagnetic diagnostics of the parameters of the solar wind and the magnetosphere, and the prediction of ionospheric disturbances. Attention is also given to the forecasting of F2-layer electron density during disturbances, mathematical methods for the short-term forecasting of F2-layer critical frequencies, and the use of numerical models of the ionosphere for ionospheric forecasting. Title: Solar-terrestrial physics: problems and perspectives. Authors: Migulin, V. V.; Miroshnichenko, L. I.; Obridko, V. N. Bibcode: 1987VeSSR...9...83M Altcode: No abstract at ADS Title: Book-Review - Sunspots and Activity Complexes Authors: Obridko, V. N.; Hejna, L. Bibcode: 1986BAICz..37..316O Altcode: No abstract at ADS Title: Cyclic variations of a connection between the interplanetary magneticfield sector structure, high-velocity streams and geomagnetic disturbances. Authors: Obridko, V. N.; Konstantinova, L. Iu.; Konakh, M. M.; Mansurov, G. S. Bibcode: 1986Ge&Ae..26..313O Altcode: No abstract at ADS Title: Cyclic Variations of the Solar Radio Flux at 10.7-CM and 3.2-CM and Their Prognostic Implications Authors: Danilchev, B. V.; Morozova, L. P.; Obridko, V. N. Bibcode: 1986BSolD...4...69D Altcode: No abstract at ADS Title: Cyclic variations of the solar radio flux at 10.7 and 3.2 cm and their prognostic implications. Authors: Danil'Chev, B. V.; Morozova, L. P.; Obridko, V. N. Bibcode: 1986BSolD1986...69D Altcode: Cyclic variations of the solar radio flux at 3 and 10 cm wavelengths have been investigated. A phenomenon of pre-minimum has been discovered to take place in 1971, when a number of indices indicated the sun-earth conditions similar to those that are usually registered at the minimum of Wolf numbers. Prognostic implications of the deviation from a regression dependence between the 3 and 10 cm fluxes are discussed. Title: On principal phases of the solar cycle. Authors: Vitinskij, Yu. I.; Kuklin, G. V.; Obridko, V. N. Bibcode: 1986BSolD1986...53V Altcode: The necessity of revision in traditional concepts of the solar cycle is argued. A new description of principal phases of the solar cycle using a set of different observational data is given. An approach to a further detailed analysis of this problem is determined. Title: Fluctuation characteristics of the interplanetary magnetic field in the frequency range 3×10-4 - 10-2Hz. Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1985Ge&Ae..25..881O Altcode: The fluctuation characteristics of the IMF for a series of proton events were studied on the basis of measurements of IMF components carried out on the Explorer 33 and 34 satellites with a time resolution of 5 sec and a measurement accuracy of 0.1 nT. The fluctuations are shown to be mainly determined by Alfven waves; the contribution of other types of waves increases during disturbed periods. The fluctuation spectrum in the whole frequency range studied cannot be described by a power law with the same exponent alpha. The value of alpha is 1.2-1.5 at the low-frequency end of the spectrum, and falls to 0.5-0.8 at the high-frequency end. Title: Solnechnye piatna i kompleksy aktivnosti Authors: Obridko, V. N. Bibcode: 1985spka.book.....O Altcode: 1985QB525.O27...... No abstract at ADS Title: Sunspots and activity complexes. Authors: Obridko, V. N. Bibcode: 1985sac..book.....O Altcode: The physics of sunspots is treated, with attention given to observational aspects and to the related theory. The structure and models of sunspot umbras and penumbras are examined from a unified point of view as well as the magnetic-field structure, wave processes, energy transfer, and the corona and chromosphere of sunspots. Analogous phenomena occurring in stars are also analyzed. It is noted that a global-type of organization is another characteristic of solar plasma. Title: The evolution of the IMF sector structure for the period of 1926 - 1980. Authors: Obridko, V. N. Bibcode: 1985BSolD1984...54O Altcode: The evolution of the IMF sector structure has been studied using an objective method with application of autocorrelation functions. It is shown that the main state of the IMF is the two-sector structure. The four-sector structure appears at the descending branch of the solar cycle and has a short life time. Title: The Behaviour of the Interplanetary Magnetic Field Fluctuations in the Frequency Interval of 10/-3-HZ to 10/-5-HZ Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1985BSolD...9...91O Altcode: No abstract at ADS Title: On Principal Phases of the Solar Cycle Authors: Vitinsky, Y. I.; Kuklin, G. V.; Obridko, V. N. Bibcode: 1985BSolD...3...53V Altcode: No abstract at ADS Title: The behaviour of the interplanetary magnetic field fluctuations in the frequency interval of 10-3 - 10-5Hz. Authors: Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1985BSolD1985...91O Altcode: The fluctuations of the interplanetary magnetic field in the frequency interval of 10-3 - 10-5Hz for the quiet period (14 - 20 July 1965) and the weak activity period (5 - 7 June 1965) are investigated. Periods of 20 - 22h, 4 - 8h and 2 - 3h are detected. The interpretation of these periods is given. Title: The Atmosphere of a Sunspot Based on Observations in the X-Ray Extreme Ultraviolet Optical and Radio Ranges Authors: Staude, J.; Furstenberg, F.; Hildebrandt, J.; Kruger, A.; Jakimiec, J.; Obridko, V. N.; Siarkowski, M.; Sylwester, B.; Sylwester, J. Bibcode: 1984SvA....28..557S Altcode: No abstract at ADS Title: Comparative Characteristics of Stellar and Sunspot Spectra Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 1984SvA....28..564B Altcode: No abstract at ADS Title: The atmosphere of a sunspot based on observations in the X-ray, extreme ultraviolet, optical, and radio ranges Authors: Staude, J.; Furstenberg, F.; Hildebrandt, J.; Kruger, A.; Jakimiec, J.; Obridko, V. N.; Siarkowski, M.; Sylwester, B.; Sylwester, J. Bibcode: 1984AZh....61..956S Altcode: A model of the solar atmosphere above a sunspot umbra is developed on the basis of published X-ray, EUV, optical, and radio observations, summarizing the findings of working conferences held at Wroclaw in November-December 1979 (Bromboszcz et al. 1981) and at Ondrejov in September-October 1981 (Bromboszcz et al., 1982). A lower-chromosphere model like that of Teplitskaya et al. (1977 and 1978) is extended upward by applying a strong temperature gradient, with T = 40,000 K and n(e) = 4 x 10 to the 10th/cu cm at z = 2000 km above the umbral chromosphere. At z = 3000-5000 km, cool loops with T = (1-100) x 10 to the 4th k are surrounded by hot (1.8 x 10 to the 6th K) coronal matter with a narrow transition layer and n(e) = 5 x 10 to the 8th/cu cm which occupies 0.8-0.9 of the total volume. Title: Comparative spectral characteristics of stars and sunspot spectra. Authors: Badalyan, O. G.; Obridko, V. N. Bibcode: 1984AZh....61..968B Altcode: A comparative analysis of the spectra of dwarf stars and a sunspot is made. It is shown that the spectral class of a sunspot depends on the index used: A sunspot has the class M0 based on the continuous spectrum, about K5 based on weak lines, and G8-K0 based on strong lines. From this it follows that the atmosphere of a sunspot cannot be likened to the average standard atmosphere of a star of any spectral class. This may be connected with the specific role of magnetic fields, the inhomogeneous structure of the atmospehre, horizontal energy transfer in a sunspot, and the force of gravity, which is different from that of a star with the same effective temperature. Title: Fluctuations of the interplanetary and geomagnetic fields in connection with proton bursts. Authors: Shelting, B. D.; Valchuk, T. E.; Feldshtein, Ia. I.; Obridko, V. N. Bibcode: 1984Ge&Ae..24..557S Altcode: A spectral analysis is made of oscillations in the interplanetary magnetic field (IMF) and geomagnetic field (GF) before, during, and after the solar flares of April 3, June 9, and October 30, 1968. Fluctuations with periods of several minutes to tens of minutes are shown to exist in the IMF and GF. Title: The Evolution of the IMF Sector for the Period of 1926-1980 Authors: Obridko, V. N. Bibcode: 1984BSolD..11...54O Altcode: No abstract at ADS Title: A working model of sunspot structure in photosphere, chromosphere and corona, derived from X-ray, EUV, optical and radio observations Authors: Staude, J.; Hildebrandt, J.; Fuerstenberg, F.; Krueger, A.; Jakimiec, J.; Obridko, V. N.; Siarkowski, M.; Sylwester, B.; Sylwester, J. Bibcode: 1983AcA....33..441S Altcode: The presented sunspot model consists of several parts which have been consistently put together: the umbral model describing the spatial distribution of thermodynamic quantities up to the transition region as derived from EUV and optical observations, the magnetic field model, the model of X-ray emission, and the S-component emission model. The model assumptions have been tested and corroborated by recently published observations with high spatial resolution obtained in the X-ray and EUV spectral range from Skylab, HRTS, and SMM, at centimeter wavelengths from RATAN, VLA, and WSRT, and by ground-based magnetograms. Title: Some trends in modern solar physics. Authors: Obridko, V. N. Bibcode: 1983PDHO....5...25O Altcode: 1984PDHO....5...25O Discussed are the main three trends in modern solar physics i.e., the study of solar plasmas as a set of discrete structural elements in time and space, the study of global organization of solar activity, and the closer relationships between solar and stellar investigations. Title: Solar Image Properties at a Site Near Norilsk Authors: Bojarskij, D. A.; Kononovich, E. V.; Kupriakov, Y. A.; Kononov, E. Y.; Smirnova, O. B.; Obridko, V. N. Bibcode: 1983ATsir1289....1B Altcode: No abstract at ADS Title: Characteristics of IMF Fluctuation Spectrum and the Level of Solar Activity Authors: Obridko, V. N.; Shelting, B. D. Bibcode: 1983BSolD...9...80O Altcode: No abstract at ADS Title: Solar image properties at a site near Norilsk. Authors: Boyarskij, Ya.; Kononovich, Eh. V.; Kupryakov, Yu. A.; Kononov, Eh. Ya.; Smirnova, O. B.; Obridko, V. N. Bibcode: 1983ATsir1289....3B Altcode: No abstract at ADS Title: Characteristics of the spectrum of fluctuations of the interplanetarymagnetic field and the level of solar activity. Authors: Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1983BSolD1983...80O Altcode: The IMF fluctuation spectrum has been analyzed for different solar activity conditions. It has been shown that the fluctuation power in the frequency range of 10-3 - 10-4 Hz increases before flares with a simultaneous decrease of the energy spectrum inclination. Title: Analysis of cyclic variations of the sector structure of the interplanetary magnetic field during the period from 1926 to 1980. Authors: Obridko, V. N. Bibcode: 1981pkem.conf...21O Altcode: No abstract at ADS Title: Structure of the atmosphere above sunspots Authors: Obridko, V. N. Bibcode: 1979SvA....23...38O Altcode: No abstract at ADS Title: Structure of the atmosphere above sunspots Authors: Obridko, V. N. Bibcode: 1979AZh....56...67O Altcode: A comparison of optical, radio, UV, and X-ray observations reveals the necessity of an improved model for the atmosphere above sunspot. A two-component model is suggested consisting of a double loop system. The loops connected with local fields in the vicinity of a sunspot have a temperature up to 700,000 K, and those connected with large-scale fields far away in the active region or with the fields of other active regions have a temperature of at least 2 million K. The relative volume occupied by the loops of both types varies with height. The model accounts for the main characteristics of all the kinds of emission considered. Title: Isolating protective shell around a sunspot umbra. Authors: Obridko, V. N. Bibcode: 1979BSolD1979...96O Altcode: No abstract at ADS Title: The Origin of Bright Umbral Elements and Forced Oscillatory Convection Authors: Obridko, V. N. Bibcode: 1979BSolD...3..101O Altcode: No abstract at ADS Title: Temperature distribution in an inhomogeneous medium with radiative equilibrium. Authors: Obridko, V. N.; Dashevskij, V. M.; Badalyan, O. G. Bibcode: 1979fsif.conf...16O Altcode: No abstract at ADS Title: Insulating Protective Shell around the Sunspot Umbra Authors: Obridko, V. N. Bibcode: 1979BSolD...4...96O Altcode: No abstract at ADS Title: Fizika Solntsa Authors: Obridko, V. N.; Teplitskaia, R. B.; Dubov, E. E. Bibcode: 1978fiso.book.....O Altcode: 1978QB3.I88t14..... No abstract at ADS Title: Physical conditions in sunspots. Authors: Obridko, V. N.; Teplitskaya, R. B. Bibcode: 1978pos..conf....7O Altcode: No abstract at ADS Title: Physical conditions in a sunspot penumbra. Authors: Obridko, V. N.; Badalyan, O. G. Bibcode: 1977BSolD1977...98O Altcode: No abstract at ADS Title: Index of compactness of solar active regions and characteristics of proton events. Authors: Kasinskij, V. V.; Ivanov, E. V.; Obridko, V. N. Bibcode: 1977IGAFS..42...34K Altcode: No abstract at ADS Title: Physical conditions in sunspots. Authors: Obridko, V. N.; Teplitskaya, R. B. Bibcode: 1976fsp..conf....3O Altcode: No abstract at ADS Title: Anomalies in the Zeeman triplet in a sunspot spectrum. Authors: Demkina, L. B.; Obridko, V. N. Bibcode: 1976fsp..conf...58D Altcode: No abstract at ADS Title: Temperature distribution in a non-homogeneous medium with radiative equilibrium. Authors: Obridko, V. N.; Dashevskij, V. M.; Badalyan, O. G. Bibcode: 1976fsp..conf...54O Altcode: No abstract at ADS Title: Variations in the intensity of photospheric lines and the continuum due to small changes of the physical parameters Authors: Badalian, O. G.; Obridko, V. N. Bibcode: 1976SvA....19..342B Altcode: 1975SvA....19..342B Formulas are derived which associate intensity variations of the solar Fraunhofer lines and continuum with small changes in model parameters. It is shown that application of these formulas to observations of facula spectra confirms the presence of a superheated region in faculae. Title: Origin of bright umbral dots in sunspots Authors: Obridko, V. N. Bibcode: 1975SvA....18..758O Altcode: 'Bright umbral dots' are investigated on the basis of a model in which they are considered the result of an instability in deep sunspot layers. A mathematical model of convective instability in the presence of a magnetic field is analyzed to obtain an overall picture of the excitation, development, and decomposition of the structures. These stages are delineated: raising of matter into a low-magnetic cavity resulting from the formation of a convective cell in deep layers of a sunspot; convective transfer of energy into the cavity, which sustains the brightness of the structure; decreases in the temperature gradient of the cavity and in the convective energy and strengthening of the magnetic field, which cuts off the influx of energy from below; gradual deexcitation and decomposition of the bright structures. The lifetime of the structures is briefly noted along with the possible use of this mechanism to determine the fine structure of the magnetic field of a sunspot. Title: Variations in the intensity of photospheric lines and the continuum due to small changes of the physical parameters Authors: Badalian, O. G.; Obridko, V. N. Bibcode: 1975AZh....52..561B Altcode: Formulas are derived which associate intensity variations of the solar Fraunhofer lines and continuum with small changes in model parameters. It is shown that application of these formulas to observations of facula spectra confirms the presence of a superheated region in faculae. Title: Catalog of solar particles events, 1955 - 1969. Authors: Dodson, H. W.; Hedeman, E. R.; Kreplin, R. W.; Martres, M. -J.; Obridko, V. N.; Shea, M. A.; Smart, D.; Tanaka, H.; Svestka, Z.; Simon, P.; Fritzová-Svestková, L.; Guitart, A. Bibcode: 1975cspe.book.....D Altcode: 1975QB505.C37...... No abstract at ADS Title: Origin of bright umbral dots in sunspots Authors: Obridko, V. N. Bibcode: 1974AZh....51.1272O Altcode: 'Bright umbral dots' are investigated on the basis of a model in which they are considered the result of an instability in deep sunspot layers. A mathematical model of convective instability in the presence of a magnetic field is analyzed to obtain an overall picture of the excitation, development, and decomposition of the structures. These stages are delineated: raising of matter into a low-magnetic cavity resulting from the formation of a convective cell in deep layers of a sunspot; convective transfer of energy into the cavity, which sustains the brightness of the structure; decreases in the temperature gradient of the cavity and in the convective energy and strengthening of the magnetic field, which cuts off the influx of energy from below; gradual deexcitation and decomposition of the bright structures. The lifetime of the structures is briefly noted along with the possible use of this mechanism to determine the fine structure of the magnetic field of a sunspot. Title: Solar Proton Flares and the Sector Structure of the Interplanetary Magnetic Field Authors: Obridko, V. N.; Mansurov, S. M.; Mansurova, L. G. Bibcode: 1974Ge&Ae..14....1O Altcode: No abstract at ADS Title: Solar proton flares and the sectorial structure of the interplanetary magnetic field. Authors: Obridko, V. N.; Mansurov, S. M.; Mansurova, L. G. Bibcode: 1974GeA....14....3O Altcode: No abstract at ADS Title: An inhomogeneous sunspot model. II. Spectral line intensification in a spot. Authors: Obridko, V. N. Bibcode: 1974BSolD1974...72O Altcode: No abstract at ADS Title: An inhomogeneous sunspot model. I. The effect of inhomogeneity on the evaluation of "empirical" models. Authors: Obridko, V. N. Bibcode: 1974BSolD1974...73O Altcode: No abstract at ADS Title: On the Polarization of the Solar Coronal Emission Lines Authors: Mogilevsky, E.; Ioshpa, B.; Obridko, V. Bibcode: 1973SoPh...33..169M Altcode: The results of the spectrophotometrical measurements of the polarization in the coronal lines Fe xiv 5303 Å and Fe × 6374 Å are given. Polarization spectrograms were obtained by two spectrographs (prism and echelle types) during the solar eclipse in Mexico on 7 March, 1970 near the region of the second contact at the heights 0.06 to 0.12 R above the limb. The polarization in the green line is about 30% (for averaged height 1.08 R). The polarization in the red line is close to the errors of the measurement and does not exceed 6%. A brief discussion of the results is also given. Title: The Spectrum of Low-Frequency Oscillations of the Magnetic Field of Sunspots, and Low-Frequency Modulation of the Radioemission from the Active Regions of the Sun Authors: Mogilevskii, É. I.; Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1973R&QE...16.1043M Altcode: No abstract at ADS Title: Polarization of the Radiation of Magnetic Stars. Authors: Demkina, L. B.; Obridko, V. N. Bibcode: 1973SvA....16..853D Altcode: 1973SvA....16..852D No abstract at ADS Title: Short-Periodic Oscillations of the Magnetic Field of the Sun as a Star Authors: Ioshpa, B. A.; Obridko, V. N.; Shelting, B. D. Bibcode: 1973SoPh...29..385I Altcode: lCorrelation analysis applied to recordings of the magnetic field and velocity of the Sun as a star reveals oscillations close to 300 s. The power spectrum of these oscillations is discussed. Title: Temperature Distribution in an Irregularity in Radiative Equilibrium. Authors: Dashevskii, V. M.; Obridko, V. N. Bibcode: 1973SvA....16..651D Altcode: No abstract at ADS Title: The spectrum of low-frequency oscillations of the magnetic field of sunspots and low-frequency modulation of radio emission of solar active regions. Authors: Mogilevskij, Eh. I.; Obridko, V. N.; Shel'Ting, B. D. Bibcode: 1973IzVUZ..16.1357M Altcode: No abstract at ADS Title: Polarization of the Radiation of Magnetic Stars. Authors: Demkina, L. B.; Obridko, V. N. Bibcode: 1972AZh....49.1046D Altcode: No abstract at ADS Title: Temperature Distribution in an Irregularity in Radiative Equilibrium. Authors: Dashevskii, V. M.; Obridko, V. N. Bibcode: 1972AZh....49..796D Altcode: No abstract at ADS Title: On the Interpretation of the π-Component Splitting in Sunspot Spectra Authors: Obridko, V. N.; Demkina, L. B. Bibcode: 1972SoPh...24..336O Altcode: It is shown that in order to explain the observed splitting of the π-component in the sunspot umbra spectrum by the hypothesis of the coexistence in sunspots of weak- and strong-field regions with opposite polarities, one has to admit the additional assumption that in the weak-field regions the Doppler halfwidth (ΔλD) and the ratio between line opacity and continuum opacity (η0) are both less than those in the strong-field regions. Title: On the wings of the sigma -components of magnetically sensitive lines in sunspots. Authors: Demkina, L. B.; Obridko, V. N. Bibcode: 1972BSolD1972..101D Altcode: No abstract at ADS Title: Large-Scale Mutual Relations of Spot Groups in Proton Complex Authors: Křivský, L.; Obridko, V. Bibcode: 1969SoPh....6..418K Altcode: The large-scale configuration of spot groups was investigated within a complex proton region. The probability of occurrence of accompanying spot groups (satellites) was studied according to the classification types, the direction of their occurrence, and the distance with respect to the proton spot group. The results obtained indicate that the condition for the generation of a proton spot group will not only rest with the known small-scale interaction of a few magnetic systems and the creation of a single group, but also with the existence of `satellites' in the neighbourhood of the proton group up to a distance of several tens of degrees. Title: Problems of solar-terrestrial physics (Symposium at Crimea). Authors: Zhulin, I. A.; Obridko, V. N. Bibcode: 1969VeSSR...4...95Z Altcode: No abstract at ADS Title: Magnetic field decay in the group 21034 during the proton flare period of July 1966. Authors: Mogilevsky, E. I.; Demkina, L. B.; Dolginova, Yu. N.; Ioshpa, B. A.; Obridko, V. N.; Shelting, B. D.; Zhulin, I. A. Bibcode: 1969AIQSY...3..222M Altcode: No abstract at ADS Title: `Bartels' active longitudes', sector boundaries and flare activity Authors: Bumba, V.; Obridko, V. N. Bibcode: 1969SoPh....6..104B Altcode: The flare activity and especially the proton-flare activity is concentrated in the zones of `Bartels' active longitudes' and in the neighbourhood closest to the sector boundaries of the interplanetary magnetic field. This concentration seems to be greater if the importance of the event increases. Title: Some comments on the long-term forecasts of proton flares Authors: Obridko, V. N. Bibcode: 1969BAICz..20...37O Altcode: No abstract at ADS Title: On the Energy Release by Magnetic Field Dissipation in the Solar Atmosphere Authors: Kopecký, M.; Obridko, V. Bibcode: 1968SoPh....5..354K Altcode: The energy release by Joule magnetic-field dissipation in the solar atmosphere is discussed. It is shown that the heating is unimportant in the case of granulation and intergranular space. In the case of spot features the additional temperatures ΔTr with the accounting of the radiation losses are no more than 30° for small new spots, ≈ 1° for the large umbrae and 300° for bright points in large umbrae. This effect gives the possibility to suggest a hypothesis on the source of temperature inhomogeneity in the spot umbra and the nature of bright points. In the chromosphere the dissipation is negligible. Title: On the Structure of the Magnetic Field of Sunspots Authors: Mogilevsky, E. I.; Demkina, L. B.; Ioshpa, B. A.; Obridko, V. N. Bibcode: 1968IAUS...35..215M Altcode: No abstract at ADS Title: On the two-component structure of the sunspot magnetic field Authors: Obridko, V. N. Bibcode: 1968BAICz..19..183O Altcode: No abstract at ADS Title: Applicability of the Existing Theories of the Formation of Spectral Lines in a Magnetic Field for Quantitative Interpretation of Solar Magnetograph Readings Authors: Obridko, V. N. Bibcode: 1968soac.conf...86O Altcode: No abstract at ADS Title: On the two-component sunspot model Authors: Obridko, V. N. Bibcode: 1968BAICz..19..186O Altcode: No abstract at ADS Title: Simultaneous Measurement of Magnetic Fields on Two Levels in the Sun's Atmosphere Authors: Zhulin, I. A.; Ioshpa, B. A.; Mogilevsky, E. I.; Obridko, V. N. Bibcode: 1968soac.conf...39Z Altcode: No abstract at ADS Title: Magnetic-Field Radiation-Scattering Matrix Derived With Allowance for the Phase Couplings of the Upper-Level Wave Function Authors: Obridko, V. N. Bibcode: 1968soac.conf...77O Altcode: No abstract at ADS Title: Radio Emission and Atmospheric Structure above Sunspots Authors: Livshits, M. A.; Obridko, V. N.; Pikel'Ner, S. B. Bibcode: 1967SvA....10..909L Altcode: No abstract at ADS Title: Radio Emission and Atmospheric Structure above Sunspots Authors: Livshits, M. A.; Obridko, V. N.; Pikel'Ner, S. B. Bibcode: 1966AZh....43.1135L Altcode: No abstract at ADS Title: Development of a Solar Absorption Line with a Split Upper Level in a Magnetic Field Authors: Obridko, V. N. Bibcode: 1965SvA.....9..398O Altcode: No abstract at ADS Title: Scattering Matrix for Radiation in a Magnetic Field Authors: Obridko, V. N. Bibcode: 1965SvA.....9...77O Altcode: No abstract at ADS Title: Computation of the Components of the Total Vector from Observations with a Solar Magnetograph Authors: Karnitskaya, Ye. A.; Obridko, V. N. Bibcode: 1965Ge&Ae...5..257K Altcode: No abstract at ADS Title: Scattering Matrix for Radiation in a Magnetic Field Authors: Obridko, V. N. Bibcode: 1965AZh....42..102O Altcode: No abstract at ADS Title: Development of a Solar Absorption Line with a Split Upper Level in a Magnetic Field Authors: Obridko, V. N. Bibcode: 1965AZh....42..502O Altcode: No abstract at ADS Title: Measurement of the Magnitude and Direction of the Magnetic Field in the Region of Sunspots Authors: Ioshpa, B. A.; Obridko, V. N. Bibcode: 1964SvA.....7..776I Altcode: No abstract at ADS Title: Measurement of the Magnitude of the Magnetic Field on the Sun Authors: Ioshpa, B. A.; Obridko, V. N. Bibcode: 1964Ge&Ae...4...12I Altcode: No abstract at ADS Title: The K232 Line Profile and the Structure of the Solar Atmosphere Authors: Obridko, V. N. Bibcode: 1963SvA.....7..342O Altcode: No abstract at ADS Title: The K232 Line Profile and the Structure of the Solar Atmosphere Authors: Obridko, V. N. Bibcode: 1963AZh....40..446O Altcode: No abstract at ADS Title: Measurement of the Magnitude and Direction of the Magnetic Field in the Region of Sunspots Authors: Ioshpa, B. A.; Obridko, V. N. Bibcode: 1963AZh....40.1015I Altcode: No abstract at ADS Title: Problem of Measuring the Absolute Magnitude of the Magnetic Field on the Sun with a Photoelectric Magnetometer Authors: Ioshpa, B. A.; Obridko, V. N. Bibcode: 1962Ge&Ae...2..451I Altcode: No abstract at ADS Title: Low-Noise Receiver for an Ionospheric Station Authors: Iospha, B. A.; Obridko, V. N. Bibcode: 1962Ge&Ae...2..454I Altcode: No abstract at ADS Title: Excitation of the Ca II K Line in the Solar Chromosphere Authors: Obridko, V. N. Bibcode: 1961SvA.....4..961O Altcode: No abstract at ADS Title: Excitation of the Ca II K Line in the Solar Chromosphere Authors: Obridko, V. N. Bibcode: 1960AZh....37.1028O Altcode: No abstract at ADS