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Investigation of Solar Rotation Using Coronal Holes
Astrophysics, 2015The rotation of the solar coronal holes was studied. Data from the Kitt Peak Observatory in the line 10830 A He I for 2003—2012 was used for this purpose. The rotation of 434 coronal holes in the latitude interval ±40° was studied. The maximum angular velocity is observed at latitudes ±15°.
D R Japaridze, B B Chargeishvili
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Detecting coronal holes for solar activity modeling
2014 48th Asilomar Conference on Signals, Systems and Computers, 2014Solar 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 +4 more
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Alfvén waves in the solar polar coronal holes
AIP Conference Proceedings, 1999We study the variation of the line width and electron density as a function of height above two coronal holes from forbidden spectral lines of Si VIII. The spectra were obtained with the Solar Ultraviolet Measurements of Emitted Radiation spectrometer flown on the Solar and Heliospheric Observatory spacecraft.
Banerjee, D. +3 more
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Peculiar Features in the Solar Coronal Hole Occurrence
Solar Physics, 2002A good knowledge of coronal hole (CH) evolution in time is relevant for the understanding of the decay and/or the stability of large-scale magnetic fields in the different heliographic latitudinal belts. Using a CH catalogue, mainly compiled from the He I line (10830 Å) measurement (Sanchez-Ibarra and Barraza-Paredes, 1992, and updated from the NOAA ...
Hofer M.Y., Storini M.
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Coronal holes and solar magnetic fields
Space Science Reviews, 1979Since 1972, nearly continuous observations of coronal holes and their associated photospheric magnetic fields have been made using a variety of satellite and ground-based equipment. The results of comparisons of these observations are reviewed and it is demonstrated that the structure and evolution of coronal holes is basically governed by the large ...
John W. Harvey, Neil R. Sheeley
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Living Reviews in Solar Physics, 2009 This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind.
Steven R Cranmer, Cranmer Steven R
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Solar activity and the formation of coronal holes
Advances in Space Research, 2000Abstract We describe the evolution of a complex of active regions belonging to cycle 22 and how its interaction with two new-cycle (23) regions resulted in the formation of several isolated coronal holes, in the development of the large coronal hole extending from the north polar hole observed in late August 1996, and in significant changes in both ...
Karen L. Harvey, Hugh S. Hudson
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On the evolutionary aspects of solar coronal holes
2023Coronal holes (CH) are large, long-lived structures commonly observed in the solar corona as regions of reduced emission in EUV and X-ray wavelengths. They feature a characteristic open magnetic field configuration along which ionized electrons and atoms are accelerated into the interplanetary space.
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Solar structures related to coronal holes
Astronomy Reports, 2007The nature of structures detected recently on the Sun in soft X rays by I.F. Nikulin (Sternberg Astronomical Institute) and called by him “partings” is discussed. It is shown that these structures are sign-reversal lines for the normal component of the curvature vector of the magnetic lines.
M. M. Molodenskiĭ, L. I. Starkova
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Energetics of Solar Coronal Holes
1991We examine the energetics of a solar coronal hole in the framework of magnetohydrodynamics (MHD). Given typical values of the observed parameters, it is estimated that the Poynting flux maintained by the solar rotation and a trailing magnetic field is potentially capable of driving and heating a wind stream in a coronal hole region.
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