The description of two major flares detected by SONG spectrometer on board the CORONAS-F mission during famous period of solar activity in October- November 2003 and their comparison with soft X-ray measured by GOES-12 is given.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

We computed chromospheric models of the Sun as a star and of nine solar analogues. The stars have a wide variety of magnetic activity levels, which allows us to study the differences in atmospheric structures induced by activity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The time series of geophysical data are chaotic and, on the other hand, extremely noisy. Thus, though there are a number of advanced methods of chaotic time series prediction, the improvement of geophysical data is crucial to succeed. Mainly, it is connected with low determinism of such time series. The improvement procedure, we are about to represent, does not directly enhance deterministic component, but regularity properties of a signal, and, therefore, causes the increase of a deterministic portion in data. The main advantage consists in the fact that the method preserves the initial structure (information) of a time series, while effectively reduces noises, even knowing nothing about its actual nature.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

The first observations containing evidence of a measurable stellar parallax were made by Thomas Henderson at the Cape of Good Hope in 1832/33. Although his response to Manuel Johnson's discovery in early 1833, that $\alpha$ Cen has a large proper motion, was to intensify observations for his remaining month at the Cape, Henderson apparently saw no urgency to reduce his observations. Instead he laboured through more routine matters, producing a catalogue of declinations of southern stars, improvements of refraction tables, and work on the solar and lunar parallaxes. It was Bessel's announcement of a determination of the parallax of 61 Cyg that finally stirred Henderson into action in late 1838.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

For multi-wavelength investigations of solar activity it may be used the intensity of cosmic ray, registered by means of neutron monitors, because the variations of cosmic ray intensity are very sensitive for local and global solar activity changes. It is important also for space weather investigation. So, we use special indices characterized the level of cosmic ray activity and some peculiarities of the space weather (Belov et al. 1999). To apply the approach, already used for cosmic ray activity calculation, to the single detector data, we have to study daily run of the counting rate. During quiet days we have in the neutron monitor data sinuslike daily variation. The characteristics of the normal for the current period anisotropy and location of the station define it. Thus, on Alma-Ata station counting rate mainly increases on the first half of day and decreases on the second one. The density changing and the anomalous anisotropy behavior lead to distortion of daily run, and the greater is of cosmic ray disturbance, the more is distortion.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

On the basis of an analogy between solar and stellar flares the optical oscillations with periods of tens of seconds observed on the EV Lac are analyzed. In terms of the diagnostic tool proposed by Zaitsev & Stepanov (1982) the main parameters of the flare loop was obtained. We concluded that source of the optical radiation is located at the loop footpoints and its pulsations are determined by the modulation of the flux of energetic particles.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The wide range frequency observations at microwaves with high spatial resolution open new ways in developing the solar physics today. They may result in most sensitive diagnostics of the upper chromosphere, TR, and corona in respect to the following parameters: - magnetic fields strength and structure; - plasma density; - periodic oscillations of plasma structures; - plasma oscillations; - temperature. The situation has been demonstrated by using a number of modern radio telescopes of interferometer type: radio heliographs at Nobeyama and Badary (SSRT), multi-element interferometer VLA. Each of them has its own important parameters, but in limited sphere of applications. In this presentation we discuss some results obtained with the reflector type instrument RATAN-600 anf possible directions in developing its parameters. The parameters of the RATAN-600, used now at the solar observations are summarized below. The most important are:

1. - high collecting area (about 1000 m2) and high flux sensitivity;

2. - wide wavelength range (1.7÷30 cm);

3. - high spectral resolution (∼5%);

4. - high polarization sensitivity (better than 1%).

1. - one-dimensional resolution (about 15 arcsec at wavelength 17 mm);

2. - limited guiding system.

We report a detailed examination about the relationship between the evolution of the H$\alpha$ flare ribbons and the released magnetic energy during an X2.3 solar flare which occurred on 2001 April 10. We successfully evaluated the released energy quantitatively, based on the magnetic reconnection model. We measured the photospheric magnetic field strengths and the separation speeds of the fronts of the H$\alpha$ flare ribbon, and estimated the released magnetic energy at the flare by using those values. Then, we compared the estimated energy release rates with the nonthermal behaviors observed in hard X-rays and microwaves. We also estimated the magnetic energy released during the flare. The estimated energy release rates in the H$\alpha$ kernels associated with the hard X-ray sources are locally large enough to explain the difference between the spatial distribution of the H$\alpha$ kernels and the hard X-ray sources. Furthermore, we reconstructed the peaks in the nonthermal emission by using the estimated energy release rates.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

RESIK is the bent crystal spectrometer aboard the CORONAS-F satellite. It is equipped with four PIN diode detectors. These detectors were used in order to detect background counts due to energetic particle contamination present within polar regions and SAA belts. At altitudes above 300 km (Coronas-F altitude is about 500 km) the population of charged particles trapped by the Earth's magnetic field consists of protons (energies between 100 keV and several hundred MeV) and electrons (energies between few tens of keV and 10 MeV). The construction of RESIK PIN diode detectors allows to sense particles with the energy above 1 MeV. We present diagrams illustrating the coupling of the Coronas-F particle environment and selected proxies of solar activity. The data shown have been collected during initial phase of mission.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 review the small number of known observations of planetary transits made in Ireland in the 18th century with particular reference to the 1769 observations of Venus by Charles Mason. Though inconclusive, there is evidence to suggest that planetary transits were instrumental in the foundation of at least one of the principal observatories in Ireland. In addition, we note the close personal involvement and the contributions of Nevil Maskelyne, the prime mover of the UK 1769 Transit observations, in the design and equipment of these observatories.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Preliminary analysis of spectra collected with the RESIK Bragg bent crystal X-ray spectrometer aboard CORONAS-F indicates the presence of many spectral features which until recently were unidentified. We present RESIK spectra in which the H-like Cl XVII Ly$\alpha$ line at 4.182 Å and He-like Cl XVI triplet components in the range 4.43 Å-4.45 Å are identified.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

Changes in Total Solar Irradiance (TSI) were studied both in time-frequency and in time-longitude aspects. The continuous wavelet analysis of TSI composite time series (Fröhlich & Lean 1998; Willson & Mordvinov 2003) revealed that the energy of thermomagnetic disturbances due to sunspots and faculae cascades into the magnetic network and facular macrostructure. The time-longitude analysis revealed large-scale patterns of radiative excesses in solar atmosphere. These patterns are organized into 2- and 4- sector structures exhibiting the effects of both activity complexes and magnetically active longitudes. Large-scale patterns with radiative excess display a facular macrostructure. These temperature patterns are causally related to long lived magnetic fields of the Sun. During activity cycles 21–23 the patterns with radiative excess tend to be concentrated around the active longitudes which are centered at about 60° and 230° in the Carrington system (Benevolenskaya et al. 1999; Mordvinov & Willson 2003).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We provide a brief overview of properties of transequatorial loops (TLs) and show that some TLs fit the description of a loop, while others appear to be the magnetic separators.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Explosive events and blinkers are two observational classes of transients seen on the quiet Sun and an investigation of the significance of and relationship between such events may be critical for understanding basic processes at work in the solar atmosphere. Our analysis showed that blinkers and explosive events are independent phenomena which have to be explained separately.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We report the “5+1” dynamical classification of the most frequently observed topologies of the magnetic field in sunspot groups associated with powerful flares (see Fig.1). The classification is based on the analysis of magnetographic and H$\alpha$ observations of more than 600 active regions on the span of 23 years (for detailed description see Ikhsanov 1982, Ikhsanov 1985).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Sub-second time structure of hard X-rays observed during solar flares by spectrometer “IRIS” on a board of CORONAS satellite are discussed. The burst duration of 80ms and FWHM about 30ms are recorded in powerful flare of August 20, 2002 year at 0828:16.77 UT. A confidence level of this peak is 6$\sigma$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html