Colour Photometry of the Solar Corona of July 11, 1991

1994 ◽  
Vol 144 ◽  
pp. 597-599 ◽  
Author(s):  
I. V. Alexeyeva ◽  
N. L. Kroussanova ◽  
M. V. Streltsova
Keyword(s):  
Solar Corona ◽  
Red Emission ◽  
Coronal Structures

AbstractThe results of photometry of colour positives of the solar corona of July 11, 1991 are presented. Observations of the white corona were made without radial niters in Jojutla (Mexico). Dependences of coronal brightness on distance in the red (640 nm) and blue (420 nm) wavelength intervals are deduced for different coronal structures up to 3.0-3.5R⊙. The effect of ”reddening“ is noted. The excess of the red emission to the blue one (I640nm/I420nm) is found to be 1.20 and 1.17 at distance of 2.2R⊙for the N-E helmet streamer (P ≃ 37°) and the N-W region of low brightness (P ≃ 339°), respectively.

scholarly journals Spectroscopic Studies of the Solar Corona II. Properties of Green and Red Emission Lines in Open and Closed Coronal Structures

2002 ◽  
Vol 54 (5) ◽  
pp. 793-806 ◽  
Author(s):  
Jagdev Singh ◽  
Takashi Sakurai ◽  
Kiyoshi Ichimoto ◽  
Yoshinori Suematsu ◽  
Aki Takeda
Keyword(s):  
Solar Corona ◽  
Spectroscopic Studies ◽  
Emission Lines ◽  
Red Emission ◽  
Coronal Structures

Calculated Coronal Magnetic Fields and Their Comparison with the Coronal Structures as Observed during Five Solar Eclipses

1994 ◽  
Vol 144 ◽  
pp. 559-564
Author(s):  
P. Ambrož ◽  
J. Sýkora
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Coronal Magnetic Field ◽  
Coronal Magnetic Fields ◽  
Solar Eclipses ◽  
Coronal Structures

AbstractWe were successful in observing the solar corona during five solar eclipses (1973-1991). For the eclipse days the coronal magnetic field was calculated by extrapolation from the photosphere. Comparison of the observed and calculated coronal structures is carried out and some peculiarities of this comparison, related to the different phases of the solar cycle, are presented.

Exploring Coronal Structures with SOHO

2000 ◽  
Vol 179 ◽  
pp. 403-406
Author(s):  
M. Karovska ◽  
B. Wood ◽  
J. Chen ◽  
J. Cook ◽  
R. Howard
Keyword(s):  
Solar Corona ◽  
Image Enhancement ◽  
Coronal Mass Ejections ◽  
Dynamical Evolution ◽  
Small Scale ◽  
Low Contrast ◽  
Contrast Structures ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Coronal Structures

AbstractWe applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

Modelling of Quiet Sun Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 169-176
Author(s):  
S. Serio
Keyword(s):  
Thermal Stability ◽  
Heat Conduction ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Thermal Stratification ◽  
Recent Progress ◽  
Coronal Loops ◽  
Dynamic Heating ◽  
Thermal Stability Of ◽  
Coronal Structures

AbstractThe 1978 paper by Rosner et al. has set the basis for a new way of understanding thermal stratification in the solar corona, taking into account the constraints of magnetic fields on heat conduction. This paper will review recent progress in modelling of coronal loops, and in particular the effects of deviations from Spitzer conductivity, stationary siphon flows and shocks, thermal stability of the transition region, and possible diagnostics of dynamic heating of the coronal plasma.

On Filter Observations of Coronal Structures in the Light of FeX 6374 Å Emission Line

1994 ◽  
Vol 144 ◽  
pp. 575-578
Author(s):  
F. I. Guetman ◽  
I. S. Kim ◽  
A. Bücher ◽  
C. A. Druzhinin ◽  
J.-C. Noëns ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Solar Corona ◽  
Emission Line ◽  
Interference Filter ◽  
Spectral Interval ◽  
Coronal Line ◽  
Interference Filters ◽  
Coronal Structures

AbstractThe red coronal line of Fe X (6374 Å) seems to be extremely suitable for filter observations due to reduced sky scattering in this spectral interval and absence of blending by Fraunhofer lines. Comparative analysis of location of Hαstructures in colour and black-white pictures of the solar corona of July 11, 1991 was carried out. A conclusion was made that care should be taken when interference filters are used for the red corona observations. Non-ideal monochromatization of present-day existing interference filters may be responsible for some ”false“ red and white coronal structures which belong to Hαprominence emission. Estimations of parameters of an interference filter for the reliable red coronal observations are presented.

Flaring Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 227-234
Author(s):  
T. Watanabe
Keyword(s):  
Solar Corona ◽  
Magnetic Reconnection ◽  
Time Scales ◽  
Solar Flares ◽  
Initial Phase ◽  
X Ray ◽  
Ionized Plasmas ◽  
First Time ◽  
Coronal Structures

AbstractThe highlights of the Japanese solar mission,Yohkoh, are presented, with emphasis on flaring structures in the solar corona. Definitive evidences of the magnetic reconnection in the solar corona are observationally confirmed for the first time. New insights in the location of hard X-ray sources are obtained. Completely blueshifted line emissions from highly ionized plasmas are seen at the very initial phase of solar flares. It is revealed that the solar corona is very dynamic in various time scales in X-ray intensities. Ample evidences of numerous flare-like activity like microflares and X-ray jets conclude that they are also the manifestation of the magnetic reconnection.

scholarly journals The Solar Corona

1980 ◽  
Vol 5 ◽  
pp. 335-341
Author(s):  
Claudio Chiuderi
Keyword(s):  
Magnetic Fields ◽  
Solar Corona ◽  
Coronal Structures

AbstractRecent observations from space have shown that the solar corona is spatially a very structured medium and temporally a very dynamic one. The consequent changes in the current theoretical ideas about coronal physics are reviewed. The role of the magnetic fields in shaping and heating the coronal structures is especially underlined.

On the Optical Polarization of the White-Light Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 601-604
Author(s):  
B. P. Filippov ◽  
M. M. Molodensky ◽  
S. Koutchmy
Keyword(s):  
Solar Corona ◽  
White Light ◽  
Scattering Theory ◽  
Radial Direction ◽  
Polarization Plane ◽  
Solar Limb ◽  
Thomson Scattering ◽  
Optical Polarization ◽  
Special Experiment ◽  
Coronal Structures

AbstractA special experiment was designed to measure the orientation of the polarization plane in the solar corona during the total eclipse of July 11, 1991. Rotating polaroids with the axes directed at +45° and at −45° of the radial direction in all directions were used. The polarization plane was found to be tangential to the solar limb everywhere with an accuracy within 1°, in agreement with the Thomson scattering theory.

On the 3D Solar Corona Structure

1994 ◽  
Vol 144 ◽  
pp. 585-588
Author(s):  
S. Koutchmy ◽  
M. M. Molodensky ◽  
J.-C. Vial
Keyword(s):  
Solar Corona ◽  
Current Sheet ◽  
3D Structure ◽  
Simple Analysis ◽  
Eclipse Observations ◽  
Analysis Of Results ◽  
True Position ◽  
Corona Structure ◽  
First Time ◽  
Coronal Structures

AbstractWe consider the 3D structure of the solar corona using eclipse observations. We use a pseudostereoscopic effect of the rigidly rotating corona to determine the true position of the main coronal structures: broad threads, rays and streamers. We find that observations collected by the “Multi-station International Coronal Experiment” are well suited for solving this problem. Formula and error estimation are given to demonstrate the feasibility of the method. An example of stereo-view deduced from a simple analysis of results coming from the 1991 eclipse is given. The observed apparent shifts allow for the first time to apprehend the true 3D structure of the corona. The structure of streamers was compared with the pecularities (pleats and cusps) of the solar heliosphere current sheet, deduced from the sourse surface. The positions of the two main streamers systems rays (near the N-E and S-limb) coincide with the pleats of the current heliosphere layer. We conclude that large helmet streamers are composed by the pleats of the heliosphere current sheet projected on the plane of the sky.

scholarly journals Observations of stellar coronae and prominences

2013 ◽  
Vol 8 (S300) ◽  
pp. 309-317
Author(s):  
Gaitee A. J. Hussain
Keyword(s):  
Solar Corona ◽  
Spectral Type ◽  
Uv Spectra ◽  
Type I ◽  
Future Prospects ◽  
X Ray ◽  
Cool Stars ◽  
Multi Wavelength ◽  
Absorption Features ◽  
Coronal Structures

AbstractX-ray and EUV observations of young cool stars have shown that their coronae are extremely pressured environments with temperatures and densities that are up to two orders of magnitudes larger than those observed in the solar corona. At the same time rapidly transiting absorption features in optical and UV spectra reveal the presence of large cool, prominence-type complexes that can extend several stellar radii. I will give an overview of our current understanding of coronal structures in cool stars from multi-wavelength observations, detailing their properties and apparent dependence on spectral type. I will also outline future prospects in this field, particularly from observations of stellar coronal environments at radio and sub-mm wavelengths.

Sign in / Sign up

Export Citation Format

Share Document