Astronomical Observatory of Kharkov National University Department of Solar, Lunar and Planetary Physics
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1999-2004 Astronomical Institute of Kharkov University. Department of Solar, Lunar and Planetary Physics

Solar Research. Publications


Akimov L.A., Beletsky S.A., Dyatel N.P. (1998) The chromospheric D3 helium emission observed at the total solar eclipse of July 31, 1981 // Astroph. And Sp. Sc. -1998- V.252

The digital images of 350 eclipse chromospheric spectra obtained with a special automatic photometer have been used to construct the image of the D3 HeI chromosphere over the range of 36°N - 42°S in latitude. The chromospheric emission comes from two very irregular layers with peaks of the intensities at the heights of 1100 - 1700 km for the layer with the dominant emission, and at the height of around 300 km for the lower layer. The distribution of the surface brightness averaged over all measured latitudes (36°N - 42°S) versus height also reveals two peaks. The energy emitted by the upper layer is determined to be 7 times larger than that emitted by the lower one. The chromospheric D3 emission is well correlated with the emission of the green corona (503.3 nm) at low heights. The correlation disappears at heights more than 1500 km. The chromosphere above active regions and spots is lowered. It is supposed that such behaviour is affected by large scale magnetic fields of the Sun and by structural elements, such as spicules and fibrils.


Akimov L.A., Beletsky S.A., Dyatel N.P. (1998) On the helium emission in the lower chromosphere. // UAA Information bulletin, N12, 1998, p.34.


Akimov L.A., Beletsky S.A., Dyatel N.P. (1999) The chromospheric D3 helium emission observed at the total solar eclipse of July 31, 1981 // Astronomical and astrophysical transections. -1999- V.18(1), p. 253-260.

The digital images of 350 eclipse chromospheric spectra obtained with a special automatic photometer have been used to construct the image of the D3 HeI chromosphere over the range of 36°N - 42°S in latitude. The chromospheric emission comes from two very irregular layers with peaks of the intensities at the heights of 1100 - 1700 km for the layer with the dominant emission, and at the height of around 300 km for the lower layer. The distribution of the surface brightness averaged over all measured latitudes (36°N - 42°S) versus height also reveals two peaks. The energy emitted by the upper layer is determined to be 7 times larger than that emitted by the lower one. The chromospheric D3 emission is well correlated with the emission of the green corona (503.3 nm) at low heights. The correlation disappears at heights more than 1500 km. The chromosphere above active regions and spots is lowered. It is supposed that such behaviour is affected by large scale magnetic fields of the Sun and by structural elements, such as spicules and fibrils.


Beletsky S.A., Bushueva T.P.(1998) DIGITIZED IMAGES FOR SOLAR ACTIVITY PATROL AT THE KHARKOV ST. UNIVERSITY ASTRONOMICAL OBSERVATORY // Izv. KRAO V. 94, Crimea 1998, p.190-192.

It is described the digitized images usage for solar activity patrol. The advantage of the CCD-observation as compared with the photographic ones is shown by examples of the active processes research in 1993-1994.


Belkina I.L, Beletsky S.A., Gretsky A.M., Korokhin V.V., Marchenko G.P. (1994) Solar activity monitoring experience with CCD-photometer. (abstr.) conf. Physics of Moon and planets.-1994.-p.18-21.

Universal photometer based on the cooled one-dimensional CCD followed by computer was constructed at Kharkov St. University Astronomical observatory. It was used to image the solar chromosphere at H HI, K CaII lines and IR HeI 1083 nm line July - August 1993 observations. The reasons leading to appearance such distorting effects as interference and others in the monochromatic observations with CCD -photometer are analysed. The observational method and data processing algorithms are proposed. The images so obtained contain the photometric information about the flares and high-speed processes in chromosphere.


Belkina I.L., Beletskiy S.A., Gretskij A.M., Marchenko G.P. (1996) CCD-observations of the Sun HeI 1083nm, Ha and K Ca II lines// Kinematika i fizika nebesnyh tel., 1996, v(t)12, N2,p(s)65-76.

The digitized monochromatic images of the Sun in HeI 1083nm, Ha and K CaII are obtained on the spectroheliograph with the CCD photometer of the Kharkov University Astronomical Observatory. Optical characteristics of the CCD receiver operating in the monochromatic regime are studied from optical to the near IR spectral range. We present the algorithms and software to remove the drawbacks inherent in this class devices. The Ha and K CaII images obtained during 1993 July-Avgust and 1994 June-October seasons (when chromospheric flares and other nonsteady processes occurred) were used to determine heliographic positions and intensities for the solar activity patrol program. The HeI 1083nm image sets were used to study line depth changes during the development of two chromospheric subflares and accompanying filaments. These flares were observed in absorption only. The tangential velocity of propagation of the perturbation in one of the filaments is evaluated.


Kurochka L.N., Belkina I.L., Beletskiy S.A., Korokhin V.V., and Marchenko G.P. (1997) Observations and Analysis of Emission from Solar Active Regions at the Edge of Balmer Continuum. //Astronomicheskiy Zhurnal., 1997, v(t)74, N3,p(s)460-465.

The first results of CCD observations of the Sun in Balmer and Pashen continua and in the Balmer precontinuum are presented. The intensity distribution in the Balmer precontinuum in a knot of the active region NOAA/USAF 7890 provides information about inhomogeneities in the electron density of the plasma along the sight line. The value of conductiong monitoring observations of this kind is argued.


Kurochka L.N. , Belkina I.L, Beletsky S.A., Korokhin V.V., Marchenko G.P. (1999) CCD- observations of the Sun in the Balmer and Pashen continue // Astronomical and astrophysical transections. -1999- V.18(1), p. 265-272.

The first results of new kind observations in the Balmer and Pashen series continua and Balmer precontinuum are presented. Such observations will provide a valuable informations about Ne-irregulaties, processes occuring in the a.r. and formation here of areas with the enhaced plasma density.


Belkina I.L., Akimov L.A., Beletsky S.A., Korokhin V.V., Marchenko G.P. EQUATORIAL CORONAL HOLES FROM THE OBSERVATIONS AT HeI l 1083 WINGS // Kinematika i Fizika Nebeshykh Tel.-2000.- V. 16, No 4.-P. 316-323.

The average intensities of areas in the blue and red wings of HeI 1083nm line for equatorial coronal holes (CH) and unipolar quit regions are determined from solar CCD images which have been taken at 0.05nm from the line centre in 1995 and 1999. These data were used for the evaluation of average doppler line shift, which is caused by the presence presence of outflows from CH (Dlh) and unipolar quit regions (Dlq). The value Dlh = -0.0032 (sm=0.0002) was received for 105 CH areas; the value Dlq=-0.0012A (sm=0.0002) was received for 41 unipolar quit regions. This result is indicative the significant difference beetween CH and quit regions in the size of average stream velocity of outflow. It means that the solar wind from CH starts to accelerate from the middle chromosphere. Taking into account the existense of the fine structure elemets in CH with radial outflow speed of 8km/s, we found that these elements are covering about 10% of the whole CH area. Tendency of |Dlh | increasing at a period near maximum of solar activity is noted.


Beletsky S. A. Results of solar chromosphere recearch in D3 and 1083 nm lines.- Manuscript. Thesis for a candidates degree by specialty 01.03.03 - Heliophysics and Physics of Solar System. Kharkov, 2000.-p.157.

The dissertation is devoted to the study of the solar chromosphere from the spectroheliograms recorded in HeI 1083 nm line and from the slitless cinematographic observations of solar eclipses in D3 helium line. For the first time the chromospheric D3 surface brightness distribution along the whole observed part of the solar limb is received from the results of two eclipse observations. The maximum of the chromosphere brightness distribution near the limb was for the first time discovered to be located at the heights less than 500 km for a considerable part of the solar limb. From the study of the 1083 nm spectroheliograms the solar wind from the coronal holes was shown to accelerate from the middle chromosphere. The results of observations of 3 flares have shown that a relation between the flare regions in the chromosphere and the "hidden" activity centres located in the corona can be found from the 1083 nm line observations.
Key words: Sun, chromosphere, coronal holes, eclipse, helium, concentration.


Akimov L.A., Belkina I.L., Beletsky S.A., Dyatel N.P. The structure and the emission of the solar chromosphere at the helium D3 line from the total solar eclipses. // Kinematika i Fizika Nebeshykh Tel.-2002.- V. 18, No xx.-P. xxx-xxx.

Maps of the chromospheric emission at the helium D3 line as functions of heliographic latitude and height obtained from cinematographic observations of the total solar eclipses 1972 July 10 and 1981 July 31 are presented. It is discovered that the helium emission is observed in separate features with the characteristic size of the supergranule of 20000-30000km along the limb mainly. The features with the maximum concentration near the height of 1400km are extended to 3000-4000km. These are present at the base of the chromosphere also, therefore the surface brightness height distributions are reveal two peaks at the heights about 1400 and 250km.
The energy emitted by the chromosphere over the height range of the lower maximum is about 5% and 10% of the total energy emitted by the chromosphere at the D3 line for the eclipses of 1972 and 1981 respectively.
It is found that the integral brightness of the quiet chromosphere for the eclipse of 1981 was twice the 1972 eclipse one. It is connected with the sunspot cycle different phases for the every eclipse.
For the inhomogeneous chromosphere it is shown the helium emission at the height range of the temperature minimum can be explained by the penetration of the coronal radiation with l< 6 nm to these heights.


2002/06/08
 
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