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Statistical Studies of Coronal Mass Ejections and Coronal Holes
Geomagnetism and Aeronomy, 2017Statistical studies of coronal mass ejections (CMEs) and coronal holes (CHs) are reviewed. The work summarizes the historical and current results of statistical studies of CMEs and CHs and their parameters that have been obtained by various authors who considered these phenomena as independent manifestations of solar activity, as well as their mutual ...
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The Geometric Spreading of Coronal Plumes and Coronal Holes
Solar Physics, 1998The geometric spreading in plumes and in the interplume region in coronal holes is calculated, using analytic and numerical theoretical models, between 1.0 and 5.0 solar radius. We apply a two-scale approximation that permits the rapid local spreading at the base of plumes (f(sub t)) to be evaluated separately from the global spreading (f(sub g ...
S. T. Suess +4 more
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Coronal holes and icosahedral symmetry
Solar Physics, 1988A new type of coordinates suitable to describe mass outflow out of coronal holes assuming symmetry under the icosahedral group is introduced.
Wolfram Neutsch, Horst Fichtner
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2019
The term coronal hole has at least three definitions: (i) the darkest patches on the solar surface as measured in UV and soft x-rays; (ii) the lowest intensity regions measured above the limb, seen either during a total solar eclipse or with an occulting coronagraph; and (iii) open-field (or open-flux) regions, which are equivalent to the footpoints of
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The term coronal hole has at least three definitions: (i) the darkest patches on the solar surface as measured in UV and soft x-rays; (ii) the lowest intensity regions measured above the limb, seen either during a total solar eclipse or with an occulting coronagraph; and (iii) open-field (or open-flux) regions, which are equivalent to the footpoints of
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Differential rotation of coronal holes
Solar Physics, 1985Using KPNO helium 10830 A synoptic charts of Carrington rotations 1716 through 1739, and by assembling a time sequence representing single latitude zone, rotational properties of coronal holes for five zones of latitudes (±10°, ±20° – ±40°, and ±40° – ±60°) have been examined. It seems that the rotation period of coronal holes is a function of latitude,
Rajendra N. Shelke, M. C. Pande
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Magnetic fields surrounding coronal holes
2008During July and August 1992 we succeeded in measuring photoelectrically longitudinal magnetic fields in areas surrounding four coronal holes, estimated from λ 10830 A spectroheliograms. We were able to estimate values of the longitudinal magnetic flux in these areas and in their active regions, as well as in parts of coronal holes, covered by our ...
Václav Bumba +2 more
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Energy budget in coronal holes
Solar Physics, 1973EUV and radio observation, supplemented by other data, have made it possible to determine the flux of energy, F sub c, conducted from the corona into the chromosphere. Of the mechanical flux input in the corona, F sub m (of which F sub c is a large fraction), there are no direct measurements but limits can be found to it.
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Radio Studies of Coronal Holes.
1981Abstract : This report describes all the projects undertaken during the entire period of the above contract, the scope of which was to study coronal holes at radio wavelengths. Chapters 1, 2 and 3 summarize work that has already been described in our previous scientific reports and published papers.
Kile B. Baker, Michael D. Papagiannis
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Hydrogen and oxygen temperatures in coronal holes
Advances in Space Research, 2000Abstract The analysis of the O VI λ 1032 and 1037 and H I Lyα λ 1216 line profiles, observed with the Ultraviolet Coronagraph Spectrometer (UVCS) onboard the Solar Heliospheric Observatory (SOHO) in a polar coronal hole within 1.5 R ⊙ and 3.5 R ⊙ during the solar activity minimum, indicates the existence of a large anisotropy in the velocity ...
E. ANTONUCCI +2 more
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1998
Five years of soft X-ray images from Yohkoh have provided us with a unique view of high-energy solar phenomena, as well as a new way of observing the lowest activity levels of the solar corona. For the first time, the Sun has been observed at soft X-ray wavelengtsHs during the minimum phase of solar cycle 22, showing an almost turned-off X-ray Sun. The
A. Sanchez-Ibarra, M. Barraza-Paredes
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Five years of soft X-ray images from Yohkoh have provided us with a unique view of high-energy solar phenomena, as well as a new way of observing the lowest activity levels of the solar corona. For the first time, the Sun has been observed at soft X-ray wavelengtsHs during the minimum phase of solar cycle 22, showing an almost turned-off X-ray Sun. The
A. Sanchez-Ibarra, M. Barraza-Paredes
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