1. Sigmoidal morphology and eruptive solar activity
- Author
-
David E. McKenzie, Hugh S. Hudson, and Richard C. Canfield
- Subjects
Physics ,Sunspot ,Geophysics ,Morphology (linguistics) ,Solar flare ,General Earth and Planetary Sciences ,Soft X-radiation ,Statistical analysis ,Sigmoid function ,Astrophysics ,Solar physics - Abstract
Soft X-ray images of solar active regions frequently show S- or inverse-S (sigmoidal) morphology. We have studied the Yohkoh Soft X-Ray Telescope video movie for 1993 and 1997. We have classified active regions according to morphology (sigmoidal or non-sigmoidal) and nature of activity (eruptive or non-eruptive). As well, we have used NOAA sunspot areas for each region as a measure of size. We find that regions are significantly more likely to be eruptive if they are either sigmoidal or large.
- Published
- 1999
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