The White-Light and Emission Coronae at the July 22, 1990 Eclipse

1994 ◽  
Vol 144 ◽  
pp. 555-557
Author(s):  
V. Rušin ◽  
E. Marková
Keyword(s):  
Solar Corona ◽  
Coronal Hole ◽  
White Light ◽  
Active Regions ◽  
Coronal Line ◽  
Line Intensities ◽  
Rapid Changes ◽  
Southwest Region ◽  
White Light Corona

AbstractVarious instruments were used to study the solar corona at the July 22, 1990 eclipse. The white-light corona of July 22, 1990 is of maximum type (the Ludendorff index of the corona’s shape turns out to be a+b = 0.04). There are many streamers nearly equally distributed around the whole Sun, except of the southwest region where large coronal hole was located. The green (530.3 nm) and red (637.4 nm) coronal line intensities display many rapid changes in active regions around the eclipse day. Huge prominences were located above the E-limb. The estimated total brightness of the white-light corona (WLC) reached its value ofJK= 1.32 × 10−6.

Solar Corona Investigation by the Coronal Line Photometer at Lomnický Peak

1994 ◽  
Vol 144 ◽  
pp. 431-434
Author(s):  
M. Minarovjech ◽  
M. Rybanský
Keyword(s):  
Solar Corona ◽  
Time Resolution ◽  
Active Regions ◽  
High Time ◽  
High Time Resolution ◽  
List Type ◽  
Type Number ◽  
Coronal Line ◽  
Global Cycle

AbstractThis paper deals with a possibility to use the ground-based method of observation in order to solve basic problems connected with the solar corona research. Namely:1.heating of the solar corona2.course of the global cycle in the corona3.rotation of the solar corona and development of active regions.There is stressed a possibility of high-time resolution of the coronal line photometer at Lomnický Peak coronal station, and use of the latter to obtain crucial observations.

scholarly journals Slight Disappearance of Prominence Plasma to the Solar Corona

1990 ◽  
Vol 142 ◽  
pp. 347-349
Author(s):  
V. Rusin ◽  
V. Dermendjiev ◽  
M. Rybansky ◽  
G. Buyukliev
Keyword(s):  
Solar Corona ◽  
Mass Balance ◽  
Plasma Exchange ◽  
Mass Exchange ◽  
White Light ◽  
Close Relation ◽  
Plasma Flows ◽  
Corona Plasma ◽  
White Light Corona

The problem of prominences-corona relationship is relativelly old. Already in 1931 Lockyer [1] showed that there is a close relation between prominences distribution and the form of white-light corona. However, this problem is still debatable and poses a number of controversial questions. One of them is the question of the energy and mass exchange between prominences and the ambient corona. It is generally assumed that the mass balance exists between the corona and prominences, but unambiguous observational proofs for prominences-corona plasma exchange are very rare. There are little data [2-4], as well, that could be used to address the problem of slight plasma flows from prominences to the corona.

scholarly journals The Large-Scale Structure of the Corona

1980 ◽  
Vol 5 ◽  
pp. 549-556
Author(s):  
Jack B. Zirker
Keyword(s):  
Solar Corona ◽  
White Light ◽  
Large Scale ◽  
Dimensional Space ◽  
Coronal Holes ◽  
Solar Limb ◽  
Active Regions ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Fast Wind

The solar corona serves as a prototype of the outer atmospheres of all cool stars. Because of its nearness we can study this prototype in more detail than any other example. Considerable progress has been made recently in understanding how the large scale structure of the solar corona controls the genesis of the solar wind and the distribution of slow and fast wind streams throughout the three-dimensional space surrounding the sun. In this review we will discuss some of the progress made in this field during the last few years. We will emphasize the observational data and the inferences that can be made more or less directly from them. T. Holzer will discuss the theoretical aspects of stellar wind acceleration in another paper in this symposium.The large scale structures of the solar corona consist essentially of three kinds: streamers, active regions and coronal holes. Figure 1 is a familiar photograph of the solar corona, obtained in white light at the total eclipse of 30 June 1973 by the High Altitude Observatory. The streamers are the petal-like structures extending out from the black lunar limb. They taper to narrow radial spikes that have been traced out as far as 10-12 solar radii (Keller, 1979). Daily measurements of the white light corona at the Mauna Loa Observatory (Hundhausen et al. 1979) and the Pic-du-Midi Observatory (Dollfus et al., 1977) since 1965 show that the streamers are fan-shaped structures that may extend 120° in solar longitude. We see them in various perspectives at the solar limb.

scholarly journals Coronascope II observation of the white light corona from a stratospheric balloon

1965 ◽  
Vol 23 ◽  
pp. 287-291 ◽  
Author(s):  
Gordon Newkirk ◽  
J. David Bohlin
Keyword(s):  
Solar Corona ◽  
White Light ◽  
Geomagnetic Storms ◽  
Scattered Light ◽  
Objective Lens ◽  
The West ◽  
West Limb ◽  
Stratospheric Balloon ◽  
White Light Corona

By use of an apodized occulting dish before the objective lens of a coronagraph the instrumentally scattered light can be reduced to about 10-9 B⊙. Observation of the streamers of the solar corona from 1.8 to 5.25 R⊙ outside of eclipse from a balloon at 30 km altitude are described. A solar streamer complex present at the west limb on 5 March 1964 was apparently the origin of the particles causing the recurrent geomagnetic storms of late 1963 and early 1964.

scholarly journals A Spectroscopic Study of the Solar Corona from Norikura and SOHO data

2001 ◽  
Vol 203 ◽  
pp. 488-491
Author(s):  
K. P. Raju ◽  
T. Sakurai ◽  
K. Ichimoto
Keyword(s):  
Solar Corona ◽  
Spectroscopic Study ◽  
Coronal Hole ◽  
Coronal Holes ◽  
Solar Observatory ◽  
Astronomical Observatory ◽  
Ion Temperature ◽  
Fast Solar Wind ◽  
Line Intensities ◽  
Source Regions

We report the results from a spectroscopic study of the solar corona using both ground-based and space-based data. Some of the current topics in coronal physics, such as the plume-interplume differences in coronal holes and wave propagation in the corona have been examined. The distribution of emission line intensities, Doppler velocities and line widths were obtained from the spectroscopic observations from Norikura Solar Observatory of National Astronomical Observatory of Japan. The coronal images in Fe IX,X 171 Å and Fe XII 195 Å from SOHO EIT were used to get the temperature map of the corona. Combining both results, we have obtained the nonthermal velocities in the coronal hole region, without the usual assumption of a uniform ion temperature. It has been found that the histogram distributions of Doppler velocities and nonthermal velocities for coronal hole and quiet regions are markedly different. The nonthermal velocities have been found to be larger by about 27 %at the interplume regions as compared to plumes which supports the view that the interplume regions are the source regions of the fast solar wind. The analysis of the time sequence spectral data shows signatures of coronal oscillations at localized regions. Periods of the order of a few minutes have been found mainly in Doppler velocities.

scholarly journals A Model for the North Coronal Hole Observed at the 1973 Eclipse, Between 1.3 and 3.2 R⊙

1980 ◽  
Vol 91 ◽  
pp. 45-48
Author(s):  
Francoise Crifo ◽  
Jean-Pierre Picat
Keyword(s):  
Coronal Hole ◽  
White Light ◽  
Difficult Problem ◽  
Absolute Calibration ◽  
Polar Cap ◽  
Good Opportunity ◽  
The North ◽  
The Absolute ◽  
North Polar ◽  
White Light Corona

At the 1973 eclipse, S. Koutchmy (Institut d'Astrophysique, Paris) obtained several pictures of the white-light corona, using polarizers and a radially-compensated filter. These pictures provide a very good opportunity for studying the large coronal hole at the north polar cap; this hole has been extensively studied during the Skylab period. On the plates of Koutchmy, we could record reliable intensities between 1.3 and 3.2 R⊙. The absolute calibration was made using the stars observed in the field at the same time. This method allows a direct comparison of well-exposed objects on a same plate and must therefore be highly reliable (see Koutchmy et al., 1978). It is well-known that the absolute calibration of eclipse plates is a difficult problem.

FeXIV Line Emission Polarization of the July 11, 1991 Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 541-547
Author(s):  
J. Sýkora ◽  
J. Rybák ◽  
P. Ambrož
Keyword(s):  
High Resolution ◽  
Solar Corona ◽  
Emission Line ◽  
Solar Eclipse ◽  
White Light ◽  
Preliminary Analysis ◽  
Line Emission ◽  
Total Solar Eclipse ◽  
Degree Of Polarization ◽  
High Resolution Images

AbstractHigh resolution images, obtained during July 11, 1991 total solar eclipse, allowed us to estimate the degree of solar corona polarization in the light of FeXIV 530.3 nm emission line and in the white light, as well. Very preliminary analysis reveals remarkable differences in the degree of polarization for both sets of data, particularly as for level of polarization and its distribution around the Sun’s limb.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

STRUCTURE AND DYNAMICS OF THE 2009 JULY 22 ECLIPSE WHITE-LIGHT CORONA

2011 ◽  
Vol 742 (1) ◽  
pp. 29 ◽  
Author(s):  
J. M. Pasachoff ◽  
V. Rušin ◽  
M. Saniga ◽  
H. Druckmüllerová ◽  
B. A. Babcock
Keyword(s):  
White Light ◽  
Structure And Dynamics ◽  
White Light Corona
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