Frequency of coronal transients and solar activity
โ Scribed by E. Hildner; J. T. Gosling; R. M. MacQueen; R. H. Munro; A. I. Poland; C. L. Ross
- Publisher
- Springer
- Year
- 1976
- Tongue
- English
- Weight
- 764 KB
- Volume
- 48
- Category
- Article
- ISSN
- 0038-0938
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โฆ Synopsis
The High Altitude Observatory's white light coronagraph aboard Skylab observed some 110 coronal transients -rapid changes in appearance of the corona -during its 227 days of operation. The longitudes of the origins of these transients were not distributed uniformly around the solar surface (51 of the 100 events observed in seven solar rotations arose from a single quadrant of longitude). Further, the frequency of transient production from each segment of the solar surface was well correlated with the sunspot number and Ca n plage (area โข brightness) index in the segment, rotation by rotation. This correlation implies that transients occur more often above strong photospheric and chromospheric magnetic fields, that is, in regions where the coronal magnetic field is stronger and, perhaps, more variable. This pattern of occurrence is consistent with our belief that the forces propelling transient material outward are, primarily, magnetic. A quantitative relation between transient production from an area and the Ziirich sunspot number appropriate to that area is derived, and we speculate that the relation is independent of phase in the solar activity cycle. If true, the Sun may give rise to as many as 100 white light coronal transients per month at solar cycle maximum.
๐ SIMILAR VOLUMES
Coronal mass ejection transients observed with the white light coronagraph on Skylab are found to be associated with several other forms of solar activity. There is a strong correlation between such mass ejection transients and chromospheric Ha activity, with three-quarters of the transients apparen