The data from the Greenwich Observatory for 1879–2003 (cycles 12–23) have been used to plot a time (Carrington rotations) vs. Carrington longitude diagram of distribution of the rotation–summed daily areas for each sunspot group. It has been revealed that most of the sunspots appear as clusters having common sources (Sunspot Formation Zones) that lie on a surface rotating with a period close to the Carrington rotation period $T=27.2753$ days. At the same time both the active longitudes and medium-size spots shift in the Carrington heliolongitude and rotate at an angular velocity corresponding to the rotation period $T\sim26.8-26.9$ days. An attempt is made to explain contradictory data on the character of rotation of sunspots and active longitudes.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The experimental and theoretic investigation of the halo (a detail of local source structure genetically associated with an active region magnetosphere) is presented by the example of the AR 5200 (October, 1988). Accordingly to the high space resolution observations of RATAN-600 and SSRT the emission of this region was almost completely ($\approx 80$%) consist of halo emission. The peculiarities of the observed halo spectrum and polarization with the model explaining these peculiarities are described. It is shown that the inversion phenomenon for the halo is strongly affected by the propagation conditions influence on the polarized emission inside the large source of this emission. The term ‘self-inversion’ is introduced for this effect. Maximum in the halo spectrum at the wavelengths 5–10 cm is clarified by the scattering and by the strong suppression of the emissivity of non-thermal electrons at these and more longer wavelengths.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The phenomena ($\sim 15$ cases) observed with Siberian Solar Radio Telescope (SSRT) in 2003–2004 years are under investigations. These phenomena are identified with CMEs by LASCO and with the associated active regions (ARs). The structure of low corona above these ARs is studied using the observations with RATAN–600. The aim of this cooperative investigation is to follow this phenomenon at the earliest stage when it is developing in low corona.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Height series of Doppler observation in $H_{\alpha}$ and $D_3$ spectral lines of solar spicules obtained by big coronagraph (53 cm) of Abastumani Astrophysical Observatory have been analyzed. Time duration of each height series was 7 s. Totally 8 different heights from the photosphere were covered. Spatial difference between neighboring heights was 1 arc sec. We found the periodic spatial distribution of Doppler velocities during height series in certain spicules. We suggest that the periodic spatial distributions are caused by propagating or standing kink waves. The wave length is found to be in the range 3500–4000 km which probably indicates to the granular origin of the waves.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We investigate the line-of-sight velocity oscillations in the sunspot NOAA 0051 during it's disk transit. A favorable concourse of circumstances (observational method, excellent seeing plus intrinsic processes in the sunspot) allowed us to observe in some instances a clear picture of waves propagating in the umbra chromosphere (chevron structure in figure 1). Thus it was possible to measure directly their phase velocity in the immediate region of sunspot umbra. These waves have a period of 2.8 min and propagate from the sunspot center outward with the phase velocity of 45–60 km s$^{-1}$ with the line-of-sight velocity amplitude of about 2 km s$^{-1}$ (figure 2, 3). The waves terminate rather abruptly on the umbra boundary and show no direct linkage with (RPW) running penumbral waves (Zirin and Stein 1972). We pointed out that in our observations the picture of propagation of the waves from the sunspot center in two opposite directions is not accompanied by the propagation of H$\alpha$ umbral flashes in these same directions. Our investigations showed that three-minute oscillations are very poorly pronounced in H$\alpha$ intensity, and no “chevron” structure is present. The spatial coherence of the waves at the umbra center is no more than 2$^{\prime\prime}$. No phase delay was found between line-of-sight velocity signals measured in H$\alpha \pm$0.2 Å and H$\alpha \pm$0.7 Å for a single spatial element. This would imply that the vertical extent of the source is comparable to the observed height scale (1000–1500 km). At the photospheric level there are clearly pronounced periodic motions (T $\sim$5 min) propagating from the umbra and from the superpenumbra to the lines of maximum Evershed velocity. One gets the impression that in some portions the Evershed flow itself is pulsating (Kobanov 2000; Rimmele 1995). Balthasar and Wiehr (1990) developed the idea that the Evershed flows may be a result of superposition of some penumbral structure affected by the underlying oscillating layers. Numerical simulations of wave propagation in a stratified magneto-atmosphere presented by Bogdan et al. (2003) show that the coupling between the fast and slow magneto-acoustic-gravity waves is confined to thin atmospheric layers where the sound speed and the Alfen velocity are comparable in magnitude. Their coherent superposition presents a large variety of Doppler and intensity time series. Interesting, some of their pictures resemble our “chevrons”.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Here we report thermodynamical properties of a a so-called “thermal plume” observed near the solar disc center in 2001. The spectral observations of two iron lines analysed have been obtained using the Vacuum Tower Telescope (Tenerife).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

This is a preliminary report on the observations of solar irradiance fluctuations with the DIFOS photometer aboard the Russian-Ukrainian satellite CORONAS-F launched in 2001. In addition the parallel ground-based spectral observations (VTT, Tenerife) carried out with the first 20-days observing space campaign are described.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

High resolution optical spectra of hydrogen and calcium lines observed with the Echelle spectrograph of the VTT at Sacramento Peak Observatory were analyzed. The observed line profiles in some parts of dark chromospheric mottles are to be matched with theoretical ones using the cloud model and several parameters (e.g. the temperature, gas pressure, flow velocity) are to be derived. Individual steps of the procedure, as well as crucial problems are discussed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We examined two “magnetic antibuoyancy” effects: i) turbulent diamagnetism and ii) magnetic advection caused by vertical inhomogeneity of plasma density in the SCZ (the $\nabla \rho$ effect). The Sun's rotation which yields the $\nabla \rho$ effect with new properties was taken into account. It is shown that at high latitudes antibuoyancy effects block the magnetic fields in the deep layers of the SCZ. However, in the region located near-equator the $\nabla \rho$ effect, modified by rotation, causes the upward magnetic advection. So it can facilitate penetration of strong magnetic fields to solar surface where they then arise in the “royal zone” as the sunspots.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

At the footpoints of loops spanning a site of flux emergence, earlier investigated in the papers by Solanki et al. (2003) and Lagg et al. (2004), we find large redshifts in the He 1083 nm line coexisting with an almost unshifted component. The speed associated with these redshifts reaches values as high as 40 km/s. We interpret these downflows in the context of several models: the free-fall downflow of matter along vertical field lines (Schmidt et al. 2000), the redshift by downward propagating acoustic waves (Hansteen 1993) and the motion of condensation regions to either side of loop footpoints (Müller et al. 2003). We present the temporal evolution of these redshifts and reconstruct the magnetic field vector in these regions for both the redshifted and the unshifted atmospheric component.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the results of Fourier and wavelet time series analysis for the high-cadence observations of an active region NOAA 8011, obtained with the Nobeyama Radioheliograph (NoRH) at the wavelength of 1.76 cm on 17.01.1997. Oscillations in brightness are found to be present with periods in the range from minutes to hours. The relationship between the active region oscillations in the microwave total intensity (I) and circular polarization (V) emission and changes of the magnetic field, deduced from the high-resolution magnetograms from MDI/SoHO, is investigated. We concentrate on the identification of different oscillation modes, the temporal behavior of the oscillations and the spatial distribution of different oscillating frequencies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present results of a study of the morphology and evolution of active regions using solar acoustic holography. These include acoustic signatures of large far-side active regions and their relationship to near-side activity indices a half rotation before and after the farside image, and the direct comparison of near-side acoustic signatures with the standard activity indicators, not only in their own right but also to calibrate the farside acoustic signature.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The East-West asymmetry of sunspot areas has been analyzed on the basis of the Debrecen Photoheliographic Data (DPD). This material provides the opportunity to scrutinize the fine details in the distributions of the East-West differences depending on spot size and central meridional distance during the ascending and the descending phase of 22th cycle.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The new model of coronal loop in the form of the double magnetic flux tube embedded into the uniform external magnetic field is proposed to explain the coronal oscillations phenomena. We investigate the MHD-waves in the magnetic flux tube, wich consists of the dense hot cylindrical cord surrounded by the co-axial shell. The magnitudes of Alfven and sound speeds in the cord, in the shell and in the environment are $V_{Ai}$, $C_{si}$, $V_{Am}$, $C_{sm}$, $V_{Ae}$, $C_{se}$ correspondingly. Under the coronal conditions we have \[ C_{se}<C_{si}< V_{Ai}<V_{Ae},\\ C_{si}< V_{Am},\ C_{se}<C_{sm}<V_{Am},\\ C_{sm}<V_{Ai}.\]To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

At high spatial and temporal resolution, coronal loops are observed to have a highly dynamic nature. Recent observations with SOHO and TRACE frequently show localized brightening “raining” down towards the solar surface. What is the origin of these features? Here we present for the first time a comparison of observed intensity enhancements from an EIT shutterless campaign with non–equilibrium ionization simulations of coronal loops in order to reveal the physical processes governing fast flows and localized brightening. We show that catastrophic cooling around the loop apex as a consequence of footpoint–concentrated heating offers a simple explanation for these observations. An advantage of this model is that no external driving mechanism is necessary as the dynamics result entirely from the non-linear character of the system.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Outside the solar disk cool emissions can be recorded. They are inserted into the surrounding hot corona and their properties are still not well known. Emissions from neutral hydrogen can be registred using the well known H-alpha line. With a coronagraph it is possible to record this line through an interference filter broad enough to avoid Doppler effects. In these observations we used a 0.3 nm width filter associated to a 15 cm aperture coronagraph equipped with a 16 bits 1K-CCD camera. The filter is wide enough to excude all usual Doppler shift effects produced during a prominence eruption.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Series of H$_\alpha$ spectra and slit-jaw H$_\alpha$ filtergrams of a quiescent prominence (QP) taken at Pic du Midi Observatory on 7 November 1977 are studied. The image processing of the H$_\alpha$ filtergrams reveals an internal structure of the prominence consisting of several arches. Series of high-resolution H$_\alpha$ spectra obtained with the slit located on selected parts of one of the prominence arches chosen for Doppler shift analysis. The prominence arch show cyclic displacement along the line-of-sight (L.O.S.) direction implying Alfven string-mode oscillations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Relations between the geomagnetic A$_p$-index and magnetic and flare parameters of the super active regions (SARs) are analysed. The small and mean SARs having the spot areas S$\le 1000\, \mu h$ seem to differ from the SARs being large $\delta$-spots (SARs-$\delta$) not only by their parameters but also by relations between them.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The active region 8210 (AR 8210) observed on May 1, 1998 is the site of numerous flares. By studying a time series (from 17:00 UT to 21:40 UT) of reconstructed coronal magnetic configurations, we give a scenario of the eruptive phenomena in AR 8210 involving the rotation of the sunspot and the complex topology in a reconnection process. We also study the time evolution of the energy and of the helicity budget. We compute the free energy in the corona, the magnetic energy rate due to transverse photospheric motions. We conclude that the photospheric motions are related to flaring activities and occur before the injections of energy into the corona. In terms of magnetic helicity, we are able to derived the relative magnetic helicity (relative to the potential field) and the helicity of the potential field configuration. The vacuum helicity (or helicity of the potential field) is constant during the time period and characterizes the complex topology. For this time period, the relative magnetic helicity does not show obvious changes related to the flaring activity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Recent high resolution observations by Lites et al. (2004) show details of facular granules at $0.12^{\prime\prime}$, including dark facular lanes. For an interpretation of these data a basic facular model is constructed, consisting of a magnetic flux sheet embedded in a plane parallel atmosphere. While the maximum contrast originates from the “hot wall” of the flux-sheet depression, the model explains the wide brightening limbward of the facular magnetic field as due to a radiative transfer effect caused by the reduced opacity of the rarefied flux-sheet atmosphere. This model produces a dark, narrow lane centerward of the facular granule even in the absence of granular flow as a consequence of the cool deep layers of the magnetic flux sheet. These results carry over to a self-consistent simulation of a flux concentration in dynamic interaction with convective motion, where the dark lane deepens and broadens.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html