Results 191 to 200 of about 10,692 (216)

Solar cycle dependence of polar coronal holes

Solar Physics, 1993
A study has been made of the polar coronal holes in relation to solar cycle activity. Important results obtained are: (i) the peak of the frequency distribution of coronal hole size shifts towards lower values as the solar cycle advances towards maximum, this being true for both the north and south polar holes, (ii) coronal hole size decreases with the
T. K. Das, T. N. Chatterjee, A. K. Sen
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Coronal holes and the solar wind

2002
Abstract Coronal holes are the darkest regions of the ultraviolet and X-ray Sun, both on the disk and above the limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties of coronal holes and how these measurements have been
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Observations of the Solar Wind from Coronal Holes

Space Science Reviews, 1994
The solar wind emanating from coronal holes (CH) constitutes a quasi-stationary flow whose properties change only slowly with the evolution of the hole itself. Some of the properties of the wind from coronal holes depend on whether the source is a large polar coronal hole or a small near-equatorial hole.
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Detecting coronal holes for solar activity modeling

2014 48th Asilomar Conference on Signals, Systems and Computers, 2014
Solar image analysis relies on the detection of coronal holes for predicting disruptions to earth's magnetic field. This paper introduces a level-set method for detecting coronal holes based on the processing of extreme ultra-violet images (EUVI) and magnetic images.
Marios S. Pattichis, Venkatesh Jatla, Rachel A. Hock, Carl J. Henney, Charles N. Arge   +4 more
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Polar Coronal Holes During Solar Cycles 22 and 23

Chinese Journal of Astronomy and Astrophysics, 2005
Data from the Solar Wind Ion Composition Spectrometer (SWICS) on Ulysses and synoptic maps from Kitt Peak are used to analyze the polar coronal holes of solar activity cycles 22 and 23 (from 1990 to end of 2003). In the beginning of the declining phase of solar cycles 22 and 23, the north polar coronal holes (PCHs) appear about one year earlier than ...
Zhang, J., Woch, J., Solanki, S.
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Coronal Holes and Solar Mass Loss

1981
During the declining phase of solar activity, and possibly at other phases, solar mass loss occurs in the form of high speed streams in the solar wind. These streams originate in low density, low temperature coronal regions, called “holes.” The physical properties of the wind streams and the holes will be discussed.
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Coronal mass ejections: Relationship with solar flares and coronal holes

2002
Abstract The Coronal Mass Ejections (CMEs) observed by the LASCO coronagraph and associated solar activity phenomena whose locations were identified by EIT and solar Hα flare observations during year 2000 indicate that about 40%, 26% and 30% of CMEs were observed when there were coronal holes (CHs) within 1–10, 11–20 and 21–40 degrees, respectively
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Picoflare jets power the solar wind emerging from a coronal hole on the Sun

Science, 2023
Lakshmi Pradeep Chitta, Andrei N Zhukov, David Berghmans   +2 more
exaly  

Coronal-Hole Detectability on Solar-Type Stars

1985
It is shown that light from the solar corona, which is integrated over the visible disk (coronal flux or irradiance), can be used to infer the disk passage of large coronal holes. Observations above the limb of Fe XIV 5303 A are used to produce a synoptic intensity map of the solar disk as it would appear in coronal light.
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Solar flare accelerates nearly all electrons in a large coronal volume

Nature, 2022
Gregory D Fleishman, Gelu M Niţǎ, Bin Chen   +2 more
exaly