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Sigmoid CME Source Regions at The Sun: Some Recent ResultsIdentifying coronal mass ejection (CME) precursors in the solar corona would be an important step in space weather forecasting, as well as a vital key to understanding the physics of CMEs. Twisted magnetic field structures are suspected of being the source of at least some CMEs. These features can appear sigmoid (S or inverse-S) shaped in soft X-ray, (SXR) images. We review recent observations of these structures and their relation to CMEs. using SXR data from the Soft X-ray Telescope (SXT) on the Yohkoh satellite, and EUV data from the EUV Imaging Telescope (EIT) on the SOHO satellite. These observations indicate that the pre-eruption sigmoid patterns are more prominent in SXRs than in EUV, and that sigmoid precursors are present in over 50% of CMEs. These findings are important for CME research, and may potentially be a major component to space weather forecasting. So far, however, the studies have been subject to restrictions that will have to be relaxed before sigmoid morphology can be used as a reliable predictive too[. Moreover, some CMEs do not display a SXR sigmoid structure prior to eruption, and some others show no prominent SXR signature of any kind before or during eruption.
Document ID
20010019889
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Sterling, Alphonse C.
(National Academy of Sciences - National Research Council Huntsville, AL United States)
Date Acquired
August 20, 2013
Publication Date
January 1, 2000
Publication Information
Publication: Journal of Atmospheric and Solar-Terrestrial Physics
Publisher: Elsevier Science Ltd.
Volume: 62
ISSN: 1364-6826
Subject Category
Solar Physics
Meeting Information
Meeting: 22nd General Assembly of the International Union of Geodesy and Geophysics
Location: Birmingham
Country: United Kingdom
Start Date: July 1, 1999
Sponsors: International Council of Scientific Unions
Distribution Limits
Public
Copyright
Other

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