Long-term behaviour of the interplanetary magnetic field is compared with that of the quadrupole harmonic of the solar axisymmetric magnetic field. Substantial correlation between them is found both on the time scale of 22-yr cycle and on the shorter time scale of several years.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Geometry of the polar magnetic field is changing during the activity cycle. Tangents to polar ray structures are usually crossed near some point below the surface. This point can be named as a “magnetic focus”. The distance $q$ between the focus and the center of the solar disk changes from the maximum value about 0.7 $R_\odot$ at solar minimum activity to the minimum value about 0.5 $R_\odot$ at solar maximum. This behavior has not been understood till now. Really, all tangents to field lines near the pole of the axially symmetric potential magnetic field described by zonal spherical harmonics cross at the same point. However, the greater is the number of a harmonic, the closer to the surface is the crossing point. As far as at activity maximum high harmonics dominate, the behavior of the focuses seems to be in contradiction with the results of the harmonic analysis. We have found that the focus depth changes could be explained by complicated relationship between the harmonics of “new” and “old” cycle near the instant of the polar magnetic field reversal.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the review of temporal variations of the solar neutrino flux, including our original results of investigations of the solar neutrino flux variations in 1970–1997.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We model hot collisionless solar corona/slow solar wind (SW) by kinetic Vlasov equation. The equatorial region with an unprescribed magnetic field is under electromagnetic action, and we have formation of a 3D Quasi-Stationary Coronal Structures (QSCS) in the current-carrying (CC) plasma with SW flows. The QSCS are generated via electromagnetic mode development in plasma having anisotropic velocity distribution function (VDF). As a result we get streamers like stratification mode, CMEs like tearing mode and heliospheric sheet like pinch mode in anisotropic plasma. The scales in the QSCS are defined via angle dependent magnetic Debye scale. The scale itself depends on value and sign of plasma anisotropy parameter which is calculated for postulated plasma VDF.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The Events of energetic particles from solar X-ray flares and shock waves have been studied. The data were taken from the National Geophysical data center (NGDC) in Boulder, Colorado, USA, Where the data were taken during the solar cycle 23rd. The 23rd cycle is the present one, that started in April 1996, and its maximum was in May 2001, and it will be decayed during year 2007. Power spectrum methods have been applied for analysis of the data given, to find the short and intermediate periodicities. The periodicity around 14 days has appeared in this analysis. This has important implications for understanding and predicting the effects of solar activity on the Earth and on the earth's atmosphere. If a Coronal Mass Ejections (CMEs) hit the Earth, it can excite a geomagnetic storm. Large geomagnetic storms, among other things, can cause electrical power which can damage satellite communications. In space CME typically drive shock waves that produce energetic particles that can damage both electronic equipment and astronauts that are outside the protection of the Earth's magnetic field. So, the prediction of the high energetic particle events is of vital importance for space navigation and airline disasters.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Analysis of time series of the solar magnetic field energy (SMFE) at various solar latitudes ($\varphi = -75^{\circ}\div +75^{\circ}$) has been done. Higuchi's technique Higuchi(1988) to measure the fractal dimension (FD) of time series has been chosen and the daily values $B(\varphi,t)$ of the solar magnetic field on the source surface for 1960-1999 have been used. These values had been computed in IZMIRAN using method by Obridko et al. (1994) As a matter of fact, Higuchi's measurements of the FD of time series $X_t$ comes to calculation of the length of the curve $l(k)\sim<\mid X_{t+k}-X_t\mid >k^{-2}$ and estimate of the coefficient $D$ in equation $\lg {l(k)}=A-D\lg k$ for considered range of $k$. The dimensions $D(\varphi,K)$ of the time series $B(\varphi,t)^2$ have been computed for various time scales $0<k<K$ $([k]=[t]=1^d)$. It has been found that at $k>10-27$ the time series of SMFE form fractal with $D\approx1.9$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In spite of the great progress of solar physics research, complete understanding of the solar activity nature is still lacking. Although everybody can observe the obvious cyclical sunspot variation, recent models of the process can not describe it quite accurately. Thus the official forecast of the 23-rd solar cycle, mainly basing on the dynamical models and precursors, was not proved. Many official predictions considered that the cycle 23 will have an amplitude higher than the previous one. In this case statistical models were neglected as the less reliable but some of those kinematic forecasts are proved to this time. This situation makes evidence that we have to not ignore statistical approaches in the study of the solar behavior at the current stage of the knowledge.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In the present study a time series analysis of three of the most well-known Sun activity data series is made: 1) the Hoyt-Schatten (Group Sunspot Number $\mbox{\textit{Rg}}$)(Hoyt & Schatten 1988); 2) the Schove and 3) the Greenland (Dye-3 ice probe) ‘cosmogenic’ $^{10}Be$ concentration series (Schove 1983, Beer et al. 1998). The series “1” is based on instrumental observations for the last $\sim$400 years. The series “2” is a reconstruction of all Schwabe-Wolf cycle magnitudes after AD 296 by use of historical reports mainly for auroras and naked-eye visible sunspots. The series “3” is an indicator for the processes in outer solar corona and interplanetary space for the epoch AD 1423–1985. Two independent methods for time series analysis are used: 1) the $T$-$R$ periodogramm analysis (Komitov, 1986); 2) the method of Kaftan (2002).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The measurements of the Doppler effect of the photosphere showed the presence of the persistent periodicity 159.9655(5) min. It is interpreted as by-product of the fast-rotating central solar core.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The results of complex investigations of solar and interplanetary large-scale magnetic fields (LSMS) are set out. A rotation of sector structures of several types of LSMF was studied analysing evolution of their primary (main) rotation periods. It is confirmed the changing of Sun's rotation regime in the middle of century XX.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A white-light flare on 2001 March 10 was well observed in the H$\alpha$ line and Ca II$\lambda$8542 line using the imaging spectrograph installed in the Solar Tower Telescope of Nanjing University. Three small sunspots appeared in the infrared continuum image, one of which showed that the infrared continuum is enhanced by 4%-6% compared to the preflare value and it almost disappeared in the continuum image for about 3 min. Near the sunspot, there appeared a hard X-ray (HXR) source, the flux of which showed a good time correlation with the profile of the continuum emission. We propose that electron precipitation followed by radiative backwarming may play the chief role in heating the sunspot.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The latitudinal time distribution of sunspots (butterfly diagram) was studied by Becker (1959) and Antalová & Gnevyshev (1985). Our goal is to revisit these studies. In the first case we check whether there is a poleward migration in sunspot activity. In the second case we confirm the results, and make more quantitative statements concerning their significance and the position of the activity peaks.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The work presents the nonlinear interrelation estimation between paleoclimatic time series using reconstructions of topological models obtained by embedding corresponding time series into $R^{n}$To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have digitized and processed the daily K-CaII-line full disk spectroheliograms from the archive of the Kodaikanal Observatory during 1907-1995. The programm has been worked out to determine the boundaries of the bright areas (plages, decayed plages, enhanced network features, K-CaII bright points and so on) with contrast that exceeded a level of the quiet Sun on the given value. About the $1.2\,{\times}\,10^6$ K-CaII active regions of different scales were processed. The coordinates, areas, the tilt and latitude-time distributions of bright features were determined. At the high latitudes the K-CaII bright points form a polar branch of solar activity at the period between the polar magnetic field reversals. This polar activity shows both 11-year's and 22-year's cycles. We found that the polar K-CaII bright point cycles proceed on average 5.5 years the sunspot cycles.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Here we analyse the solar cycle (SC) 23 behavior and we also make a comparison with some previous cycles and present a few aspects concerning the forecasts made for SC 23 maximum. As regards the following cycle, in accordance to other early predictions, our empirical method, based on observing the flare energy release during the descendant phase of the precedent SC, estimate that the amplitude of SC 24 will be low.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Solar magnetic field polarity reversal (SMFPR) happens every 10-11 years. However untill now there is no clear understanding in what way this process is carried out. Results represented here are a by-product of the coronal hole study based on taken from Web-archive XUV corona images (Yohkoh and EIT/SOHO), white-light corona pictures(SOHO/LASCO) and Kitt Peak coronal hole (CH) 1083 nm maps. Observations used cover the minimum, maximum and a part of declining phase of 23-d cycle (1996-2004).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

This paper presents the results of a comprehensive analysis of the dynamics of the sun's global magnetic structure, solar wind parameters, the interplanetary magnetic field and geomagnetic activity during fast global changes of magnetic fields on the Sun.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We explore a full sphere (2D axisymmetric) kinematic solar dynamo model based on the Babcock-Leighton idea that the poloidal field is generated in the surface layers from the decay of tilted bipolar solar active regions. This model incorporates the helioseismically deduced solar rotation profile and an algorithm for buoyancy motivated from simulations of flux tube dynamics. A prescribed deep meridional circulation plays an important role in the advection of magnetic flux. We specifically address the parity issue and show that – contrary to some recent claims – the Babcock-Leighton dynamo can reproduce solar-like dipolar parity if certain reasonable conditions are satisfied in the solar interior, the most important requirement being that the poloidal field of the two hemispheres be efficiently coupled across the equator.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The reconstruction of sunspot numbers from the decadal radiocarbon series was made for the time interval 8005 B.C. - 1945 A.D using five-box carbon exchange model. Analyses showed apparent persistency in the reconstructed Wolf number series. It indicates the existence of long-term memory in solar activity. Nonlinear forecast of the mean value of Wolf number is made for the next 40 years using obtained radiocarbon proxy. Comparison of the results with the long-term forecasts of the other authors was performed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We study the sensitivity to AR of three photospheric lines, comparing experimental results, from THEMIS observations, with spectral synthesis, demonstrating the inappropriateness of using these lines as indicators of quiet sun modifications, because their variations in the active regions. We try to reconstruct the cyclic lines behavior.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html