Angular positions of the brightest coronal streamers observed during the total solar eclipses (TSEs) in 1870-2001 are compared with calculated tilts of the heliospheric current sheet (HCS) in 1976-2001 and with reconstructed ones in 1870-1976.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A new technique of nonlinear interrelations between time series developed by Marwan & Kurths, (2002) has been applied to the sunspot data. By using this tools we have investigated synchronization and phase difference in annual sunspot areas — time series available for Northern and Southern Hemispheres of the Sun.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Traditionally the $\alpha - \omega$-dynamo is regarded as a basic theory of solar activity (SA) cycle. Here the model of solar magnetic cycle based on the new MHD-solutions for the mean large-scale magnetic field is presented. The hypothesis of gyrotropic plasma turbulence and cyclic restoring of the poloidal magnetic field from the rising toroidal magnetic flux tubes due to the $\alpha$-effect is not used (see Solov'ev and Kiritchek (2004)).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Polarization of radio emission on the solar disk was studied according to of Nobeyama radio heliograph observations during 1992-2003. The latitude-time diagrams of polarization circular radio emission were constructed. For a decrease of the noises we used several solar images for a day. We found polarization drifts of radio emission in the high-latitudes activity and at latitude band of the sunspots. Process of the magnetic field reversal of the large-scale magnetic field in polarization of radio emission of the Sun was found during 22-23 cycles. An analysis of polarization for the structures various brightness temperatures has been carried.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We investigated variations of the radio emission of the whole Sun at 1.76 cm obtained and archived at the Nobeyama radio heliograph in 1992–2003. For this purpose the daily data of the intensity and also right/left circular polarization of the radio emission with one-second average were processed. It was found that 3 minutes oscillations are present at the different phases of solar activity, including the minimum of activity. Especially conspicuous these oscillations present in a difference between the right and the left circular polarization. Intensity of the oscillations changes with a level of the solar activity. As we register fluctuations from the full Sun that their source can be not only sunspots but also and chromosphere of the Sun. Spectral analysis of the presence of 3-minute oscillations in polarization of the solar radio emission shows that there exist modulation with the periods of 27 and 157 days.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

According to daily observation SOHO/MDI during 1996-2003 and NSO/KP Vacuum Telescope during 1978-2003 magnetic elements with intensity of the magnetic field above background have been allocated. The knots were then identified that allowed to trace their displacement comparatively of heliographic grid. Thus, fields of speeds for the period with 1978 on 2003 have been constructed. Variations of speed meridional circulation are found out. The basic direction of speed meridional drift is directed to poles. At the same time it is shown, that during a maximum of activity at latitude less than $20^o$ arise currents in the direction of equator. Streams in the direction to equator arise and during a minimum of activity at latitude about $40-60^o$. Fields of speeds on various phases of solar cycle are constructed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Latitude distribution of the solar convective zone rotation rate is studied by expanding it in a complete system of orthogonal modes (both symmetric and asymmetric relative to the equator). We find the solution to the problem of determination of the rotation rate of using helioseismic data available for the latitudes of $0^{\circ}$, $30^{\circ}$, $45^{\circ }$, and $60^{\circ}$ of one (for instance, the northern) hemisphere. The pole, $90^{\circ}$, will also be included into the above latitude list for the reason to be disclosed below. It is known that any rotation rate can always be represented by an expansion in a complete system of orthogonal vector spherical harmonics with a zero superscript (see, e.g., Varshalovich et al. 1988).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We are considering below some complex problems which arise in theoretical description of the processes developing in convective zones of rotating stars. It is common knowledge that the solutions of the starting nonlinear equations of equilibrium or motion may have singularities at the rotation axis, whose elimination in the case of equations of an even more general nature including spins was treated in quantum mechanics by invoking a numerical procedure (see, e.g., Varshalovich et al. (1988)). If spin effects are disregarded, these equations, which describe general representations of conventional and Alfven velocities as expansions in orthogonal vector spherical harmonics can be cast in an analytical form Vandakurov (1999).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The longitudinal distribution of sunspot activity for 1917-1995 is studied using vector sums of sunspot areas. It is shown that the sunspot distributions behave differently during the Ascending phase and Maximum (AM) of the solar cycle on one hand and for the Declining phase and Minimum (DM) on the other depicting maxima around roughly opposite longitudes. While the maximum of the distribution for the AM period is found around the Carrington longitude of 180$^\circ$, the maximum for the DM period is at the longitude of about 0$^\circ$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the long term variation of solar corona based on SOHO/EIT observations from 1996 to 2004. EIT provides diagnostics of bulk corona in three channels with overlapping temperature range from 0.5 MK to 2.7 MK and with high spatial resolution. We find that the coronal emission measure increases by a factor of 4 from $2.0\times10^{27}$ cm$^{-5}$ at the solar minimum to $8.0\times10^{27}$ cm$^{-5}$ at the solar maximum. In the meantime, the overall temperature of the corona increases from 1.3 MK to 1.7 MKTo search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Recent high-resolution observations provide us with key information that allows us to begin to assemble a coherent theoretical picture of the formation and maintenance of a sunspot and its complex thermal and magnetic structure. A new picture of penumbral structure has emerged from observations, involving two components having different magnetic field inclinations and remaining essentially distinct over the lifetime of the spot, with little interchange of magnetic flux. The darker component, with more nearly horizontal magnetic field, includes “returning” magnetic flux tubes that dive down below the surface near the outer edge of the penumbra and carry much of the Evershed flow. The configuration of these flux tubes can be understood to be a consequence of downward pumping of magnetic flux by turbulent granular convection in the moat surrounding a sunspot. This process has been demonstrated in recent three-dimensional numerical simulations of fully compressible convection. The process of flux pumping is an important key to understanding the formation and maintenance of the penumbra, the hysteresis associated with the transition from a pore to a sunspot, and the behavior of moving magnetic features in the moat.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

New methods of local area helioseismology provide three-dimensional maps of sound-speed variations and mass flows in the upper convection zone, giving important insight into the internal structure and dynamics of sunspots and active regions. Most of these results are obtained from SOHO/MDI data using the method of time-distance helioseismology (or acoustic tomography). Robustness of this method has been significantly improved by incorporating most important wave propagation effects and stochastic properties of solar oscillations. Time-distance helioseismology reveals that developed sunspots have a two layer structure: a relatively thin sub-photospheric layer of lower sound speed, and a deeper layer of higher sound speed. The mass flows in the upper layer are typically converging and directed downward, while in the deeper interior the flows are mostly diverging. These results support the cluster model of sunspots suggested by Parker. New observations also provide interesting information about emerging magnetic flux, formation and evolution of active regions and complexes of activity, and allow us to investigate effects of sub-photospheric dynamics of active regions on the global circulation of the Sun and also small-scale rapid shear flows associated with flares and CME.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present results from realistic, high resolution, simulations of solar magneto-convection. Simulations were run with both a mean vertical and a mean horizontal field. The magnetic field is quickly swept out of the granules and meso-granules and concentrated in the intergranular lanes.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The solar active regions observations were carried out with facilities for multi-spectral investigations of solar atmosphere on Large solar coronagraph of Sayan observatory. The facilities permits to perform the spectral observations in selected chromospheric and coronal lines simultaneously with obtaining of $H_\alpha$ and He I images.

In this work we analyze the results of spectral observations in the range from 10824 Å to 10835 Å (the He I 10830 Å and Si I 10827 Å lines) and images of the sunspot umbrae in the He I 10830 Å.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Fundamental information about the nature of solar filaments and governing physical processes are retained in their small-scale structure and dynamics. The paper reviews some recent high resolution studies of filaments, with emphasize on potential impact on current understanding of their physical nature.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The chromosphere is an intriguing part of the Sun that has stubbornly resisted all attempts at a comprehensive description. Thus, observations carried out in different wavelength bands reveal very different, seemingly incompatible properties. Not surprisingly, a debate is raging between supporters of the classical picture of the chromosphere as a nearly plane parallel layer exhibiting a gentle temperature rise from the photosphere to the transition region and proponents of a highly dynamical atmosphere that includes extremely cool gas. New data are required in order settle this issue. Here a brief overview of the structure and dynamics of the solar chromosphere is given, with particular emphasis on the chromospheric structure of the quiet Sun. The structure of the magnetic field is also briefly discussed, although filaments and prominences are not considered. Besides the observations, contrasting models are also critically discussed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have developed the technique and software to observe and process spectral data obtained with the CCD camera. It makes possible to construct two-dimensional maps of Doppler velocity and intensity in solar features simultaneously at two levels in the solar atmosphere. We present some results derived from study of the structure and space-time variations of the Doppler velocity in the region of quiescent filaments in the chromosphere (the $H_{\beta}$$\lambda 486.1$ nm line) and under filaments in the photosphere (the Fe I $\lambda$ 486.3 nm. and Fe I $\lambda$ 485.9 nm lines). We came to a conclusion that motions in quiescent filaments consist of both the stationary and oscillatory components and follow helical trajectories.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present observations of the dynamic evolution of photospheric magnetic elements in the G-band, magnetograms and Dopplergrams. The observations were obtained with the Swedish 1m Solar Telescope on La Palma at close to the diffraction limit of $0{\hbox{.\!\!^{\prime\prime}}}1$. In the most quiet regions we observe individual bright points in the G-band with corresponding magnetic signal in the magnetograms. Where the filling factor of the magnetic field is larger, the bright points interact when advected by the granular and super-granular flow-fields, flux sheets form and fragment. The plage region of the decaying active region is filled with more complex topologies like ribbon structures with darker interior and bright, knotted edges. These change into flower-like shape when small in extent and into micro-pores when the flux region is larger in extent. The magnetic elements in the plage region are associated with upflows with strong downflows in the immediate vicinity in the low-field region.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The temperature, velocity and magnetic field structures of solar atmosphere are extremely in-homogeneous under consideration on a small spatial scales. This fact is the reason of significant difficulties in the attempts of disambiguous interpretation of observations. Particularly informative for investigation of the complex polarized radiation formation processes in the dynamic solar atmosphere with a fine-structured organization of magnetic fields are the distributions across the solar disk of the amplitude asymmetry ($\delta a$) and area asymmetry ($\delta A$) of Stokes profiles, as well as of the strength ratios $R$ in different combinations of spectral lines. At this paper such information has been obtained using the Stokesmeter of the STOP telescope at the Sayan observatory. It was found that for some Fraunhofer lines the distribution of $R$ has an evident equatorial-polar asymmetry, which is difficult to explain yet. Additionally this paper presents some new results of the theoretical simulation (with different parameters of magnetic flux tubes models and of the medium in their neighborhood) of the center-to-limb variations of $\delta A$ on the example of the FeI $\lambda 525.02$ nm spectral line and of the $R = B_{525.02}/B_{524.70}$. The conclusion is made that a reasonably good agreement theory and experimental data can be achieved, for the time being, only for the central regions of the disk.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A series of coronal magnetograms, related to the active region NOAA 9068 is derived using the effects of the quasi-transverse (QT-) propagation at microwaves. In the assumption that the product of the electron density $N$ and the scale of magnetic divergence $L_d$ is constant and equal to $10^{18}$ cm$^{-2}$, the sensitivity of the measurements peaks at $B(G) \approx 180 \, \lambda^{-4/3} (cm)$, where $\lambda$ is the observational wavelength. The radio maps of the Sun taken with the Solar Siberian Radio Telescope (SSRT) at $\lambda = 5.2$ cm were sampled and converted into the 2D coronal magnetograms supplying absolute values of the total magnetic vector $\vec B$ in the range 10-30 G. Each coronal magnetogram covers the portion of the microwave source in the active region affected by the QT-propagation conditions in the corona.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html