Recent observational work has shown that the emission in different layers of the solar atmosphere can de described statistically. For example, Pauluhn et al. (2000) show that the frequency distribution of quiet Sun emission in EUV lines is well fit by a lognormal distribution. In addition, Parnell (2002) has shown that the frequency distribution of discrete magnetic elements in the quiet Sun is well fit by a Weibull distribution. These distributions arise naturally from fragmentation studies of materials such as polymers and sediments. It is suggested that fragmentation and its related phenomena may be of use in describing the physics of how the above distributions appear on the Sun.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Changes of extreme ultraviolet (EUV) Solar flux were registered during the Annular Solar eclipse of May 31 2003, when CORONAS-F satellite (Oraevsky et al., 2002) intersected thrice a zone of the Solar eclipse. During these periods the solar emission was measured in visible and extreme UV spectral regions (near $L_{\alpha} = 121.6$ nm by VUSS instrument). Records by VUSS ($\sim 120$ nm) and the optical (visible) channel of EOS instruments on UTC scale for May 31, 2003 are given on Fig. 1.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

Four series of coronal images have been obtained by the expedition of Abastumani Astrophysical Observatory during the August 11, 1999 total solar eclipse with the help of the photographic mirror-lens polarimeter (D=150 mm, F=1000 mm). Each series includes three images corresponding to three positions of the polarization analyzer. The position of the solar disk center relative to the Moon's center has been determined beforehand. In addition, the background skylight polarization and intensity are calculated. All measurements are absolute given in units of the sun's average surface brightness. Equatorial electron densities and temperatures are determined. Our data are compared with previous absolute measurements.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a method how to describe analytically a magnetic field distribution in the vicinity of a large interplanetary flux rope. The field consists of the pre-existing one and an additional current-free part. This work was supported by INTAS grant 03-51-6206, AV ČR project S1003006, and RFBR grant 03-02-16340.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Recent results of two observation campaigns (October 2002 and October 2003) are presented with the objective of understanding the onset of flares and CMEs. The magnetic field was observed with THEMIS and MDI, the chromosphere with the MSDP operating on the German telescope VTT and on THEMIS, the EUV images with SOHO/CDS and TRACE, the X-ray with RHESSI. We show how important is the magnetic configuration of the active region to produce CMEs using two examples: the October 28 2003 X 17 flare and the October 22 2002 M 1.1 flare. The X 17 flare gave a halo CME while the M 1.1 flare has no corresponding CME. The magnetic topology analysis of the active regions is processed with a linear-force-free field configuration.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

An analysis of the distribution of coronal brightness in the UV radiation according to SOHO/EIT in the wavelengths 171Å, 195Å and 304Å was carried out. A change of coronal brightness at the heights $1.02R-1.20R$ radius of the Sun was considered during 1996-2003. The distribution of brightness of the corona at the various heights depends on the phase of the solar cycle. Brightness of the corona at the heights more 1.05R in the wavelengths 171Å and 195Å has the greatest brightness during an epoch of the maximum activity. Brightness of the internal corona at the heights less $1.05R$ has the lowered brightness during this period. The maximum intensity of the corona 304Å was observed in the maximum activity at all heights. Comparison brightness of the corona with the number bright points in UV was carried out. For this purpose the bright points in the wavelength 304Å were allocated on the solar disk of the daily observations. The number of the bright points has the maximum on the phase of the minimum activity while the area of the bright regions has maximum in the maximum activity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

An erupting prominence seen by SOHO/EIT was tracked into the field of view of the LASCO C2 and C3 coronagraphs where it developed into the core of a structured CME. The erupting prominence was deflected by an angle of $\sim 20^{\circ}$ towards the north pole whereas the consequent core of the CME and it's leading edge propagated in the outer corona at constant position angle. The prominence material underwent a constant acceleration phase until a height of $\sim$1.5 solar radii before it started to decelerate up to a distance of 5.0 solar radii. An inflow of plasma with a speed of about 70-80 km/s was discovered in the EIT observations at a height of 1.5-1.2 solar radii in the course of the prominence eruption, matching in time the prominence deceleration phase. The downflowing material followed a curved path, suggestive of the apex of a contracting magnetic loop sliding down along other field lines.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The results of research of halfwidhts ($\Delta\lambda$) and intensities (W) of Fe X $\lambda 6374 \AA$ and Fe XIV $\lambda 5303\AA$ spectral lines using observations obtained with the Large coronagraph of the Sayan observatory in 1968-1983 show the inverse correlation between $\Delta\lambda$ and W always exists for Fe X $\lambda 6374 \AA$; it takes place at all latitudes at the same height as well as with height irrespectively of activity level. For Fe XIV $\lambda 5303 \AA$ this correlation varies from direct to inverse depending on activity level. It is shown that relation type between $\Delta\lambda$ and W for different spectral lines is determined by different coronal structurednesses in these lines.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A short compilation of results of spectral observations of nonthermal velocities $\xi$ in a wide range of temperatures in X-ray, EUV, UV and visual wave-lengths has been made. Relationship between the $\xi$ and electron temperature T for chromosphere, quiet and active corona, coronal holes (CHs) and flaring plasma is considered.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

There are dozen instruments successfully operating aboard the solar satellite CORONAS-F, which was launched in the summer of 2001. Among them are two (Polish-led) Bragg crystal spectrometers – RESIK and Diogeness – recording solar flare and active region spectra. A short description of the CORONAS-F satellite operation is presented together with that of the two Polish spectrometers, stressing their unique characteristics. The average spectra have been derived and shown here, covering the wavelength range between 3 Å and 7 Å. Future steps in the analysis of the large database collected are outlined.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Specific features of magnetic reconnection in solar flares are briefly reviewed and illustrated. In particular, the large-scale structure and dynamics of large flares are interpreted in terms of the rainbow reconnection model. The role of the betatron effect in collapsing magnetic traps is considered.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We describe two flares of GOES class M5.7 and 1.5 which were observed simultaneously by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) and NoRH (Nobeyama Radio Heliograph). Both flares exhibit slow motions suggestive of changing magnetic shear, loop expansion, or gradual reconnection. One flare is clearly a coronal hard X-ray and microwave flare.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

During the period from 19 October to 4 November 2003, there was a sudden and high Solar activity. During this period the sunspot area increased from 1110 10E-6 Hemisphere on 19 October to 5690 10E-6 Hemisphere on 30 October, then decreased to 1110 10 E-6 Hemisphere at 4 November 2003. Also, the radio flux of 10.7 cm increased from 120 sfu on 19 October to 298 sfu on 26 October, then decrease to 168 sfu on 4 November 2003. There were two eruptive solar proton flares released on 26 and 28 October 2003, where the last one is the most eruptive flare recorded since 1976 with importance X17/4B. The proton event affecting the Earth's environment, with energy ¿10 MeV is 29500 particle flux units, on 29 October 2003 as recorded by spacecraft SOHO, due to the solar flares of 28 October. The peak of the Solar cycle 21 was at 1979, but high energetic Solar flares, or secondary peaks, occurred at the declining phase in 1981, 1982, and 1984 before the solar activity minimum in 1986. Also, the peak of the solar cycle 22 was at 1989 but high energetic solar flares occurred at the declining phase in 1991, 1992, and 1994, before the solar activity minimum in 1996. Then the secondary peaks were occurred during 2 to 3 years after the first peak, as deduced from the last five solar cycles. The period of 19 Oct. to 4 Nov. 2003 is the second peak of the solar cycle 23, where the main peak of the solar cycle 23 was at 2001. There are many terrestrial influences, due to the solar activity during Oct.-Nov. 2003. These influences are studied in details, especially the geomagnetic storms and their effects on humankind daily activity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The observations of the bursts with fine structures are one of the best remote sensing probe of the primary energy release sites in solar flares. The Siberian Solar Radiotelescope (SSRT) gives us the unique possibility of direct measurements of their positions with temporal resolution up to 14 ms and spatial resolution of a few arcsec. National Astronomical Observatories of China (NAOC) spectropolarimeters (5.2–7.7 GHz) provide us with the simultaneous spectral data around the SSRT receiving frequency (5.7 GHz). An analysis is made of the subsecond pulses observations: short wide range pulses, U-type microwave bursts, the bursts with zebra pattern.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

More than 30 active regions were observed on the Sun during October-November 2003 by SOHO. Approximately half of such regions induced hard X-ray and $\gamma$-ray emission and some solar flares with class M and X were detected during this time by GOES, RHESSI and other experiments. 5 solar flares were detected by AVS-F instrument onboard CORONAS-F satellite. Nuclear $\gamma$-emission lines were detected during some flares observed in this period, in particular, during all flares on October 29 2003.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

AVS-F instrument (Amplitude-Time Spectrometry of the Sun) is the system of an electronics engineering for onboard data gathering from two detectors: scintillation (CsI (Tl)) detector SONG-D (SOlar Neutrons and Gamma quantums) of complex of detectors SKL (in low and high gamma-band) and from semiconducting detector (X-ray semiconducting spectrometer) XSS-1 (in X-ray band). The experiment is carried out on the satellite CORONAS-F launched on July 31 2001. During more than 2,5 year of apparatus operation more than 30 of solar flares were detected. Characteristics of observed solar flares are presented in this article.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

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

We describe fully consistent NLTE radiation hydrodynamic simulations of the propagation of acoustic waves in sunspot umbrae. In contrast to the case of the quiet internetwork Sun, we find that the observed behavior of the resonance lines of singly ionized calcium (H and K lines) cannot be explained without adding non-acoustic heating. The best agreement with observations is obtained with an extra heating term as a function of height that is constant per volume.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html