Major H alpha flares in centers of activity with very small or no spots
Helen W. Dodson,E. Ruth Hedeman +1 more
TLDR
In the years 1956-1968 these flares represented ∼ 7% of all confirmed flares of importance ⪖ 2 as mentioned in this paper, in which the flares were of unusually long duration and rose to maximum intensity slowly.Abstract:
Major Hα flares (importance ⪖ 2) in plages with only small or no spots constitute a rare but well observed aspect of solar activity. Information relating to 83 such flares has been assembled and studied. In the years 1956–1968 these flares represented ∼ 7% of all confirmed flares of importance ⪖ 2. In general, the flares were of unusually long duration and rose to maximum intensity slowly. A flash phase was often absent or poorly defined. In a number of cases, the flare emission included two bright filaments more or less parallel. The flares usually occurred during the late, flare-poor phase of a center of activity, and their outbreak did not presage a resurgence of activity in subsequent rotations. The flares were frequently associated with the position of dark filaments.read more
Citations
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Journal ArticleDOI
An Observational Overview of Solar Flares
Lyndsay Fletcher,Brian R. Dennis,Hugh S. Hudson,Säm Krucker,K. J. H. Phillips,Astrid Veronig,Marina Battaglia,L. Bone,Amir Caspi,Qingrong Chen,Peter T. Gallagher,P. T. Grigis,Haisheng Ji,Haisheng Ji,Wei Liu,Wei Liu,Ryan O. Milligan,Manuela Temmer +17 more
TL;DR: An overview of solar flares and associated phenomena, drawing upon a wide range of observational data primarily from the RHESSI era, is presented in this paper, where the focus is on different areas of flare phenomena (footpoints and ribbons, coronal sources, relationship to coronal mass ejections) and their interconnections.
Journal ArticleDOI
Solar activity and the corona
TL;DR: In this article, the authors put together what we have learned about coronal structures and phenomenology to synthesize a physical picture of the corona as a voluminous, thermally and electrically highlyconducting atmosphere responding dynamically to the injection of magnetic flux from below.
Journal ArticleDOI
The Dependence of Large Flare Occurrence on the Magnetic Structure of Sunspots
TL;DR: In this article, the authors studied 8 yr of active region observations from the United States Air Force/Mount Wilson data set, supplied by the NOAA World Data Center, to confirm the relation between δ spots and large flares.
Journal ArticleDOI
Driving major solar flares and eruptions: A review
TL;DR: In this article, the authors focus on the processes that energize and trigger M-and X-class solar flares and associated flux-rope destabilizations and suggest a critical role for the emergence of twisted flux ropes into pre-existing strong field for many, if not all, of the active regions that produce M- or X class flares.
Journal ArticleDOI
Global Properties of Solar Flares
TL;DR: In this article, the impulsive phase of the flare dominates the energy and momentum in the electromagnetic field, not in the observable plasma, and also point out that energy and energy in this phase largely reside in the magnetic field.
References
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Journal ArticleDOI
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Journal ArticleDOI
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TL;DR: In this paper, the authors summarized observations of solar and space phenomena related to the McMath region Number 8461 which passed over the solar disk during the 1966 Proton Flare Project period and produced two important solar particle events on August 28 and September 2.
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