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Spatial distribution of XUV emission in solar flares

Journal Article · · Astrophys. J., v. 201, no. 3, pp. 735-739
DOI:https://doi.org/10.1086/153939· OSTI ID:4107818
The spatial distribution and time evolution of flare plasmas are studied with observations obtained with the NRL XUV spectroheliograph aboard Skylab. The hot 10--20 million degree plasma (Fe xxiii--xxiv) is located at the position of a gap in emission of the cooler plasmas (He ii to Fe xiv-xvi) which often take the form of two ribbons. As the flare cools, the Fe xxiii-xxiv plasma disappears and the region between the two ribbons is filled gradually with emissions from lower stage ions. Comparison between spectroheliograms and magetograms shows that the basic magnetic field configuration associated with the flares observed is a low- lying (4000 to 13,000 km) loop or arch structure. The flare apparently results from a plasma instability in the loop which produces localized heating in a small volume, usually near the top of the loop. Geometrical and physical properties of the hot flare plasma are presented, and implications of the observational results are briefly discussed. (AIP)
Research Organization:
Naval Research Laboratory
Sponsoring Organization:
USDOE
NSA Number:
NSA-33-018152
OSTI ID:
4107818
Journal Information:
Astrophys. J., v. 201, no. 3, pp. 735-739, Journal Name: Astrophys. J., v. 201, no. 3, pp. 735-739; ISSN ASJOA
Country of Publication:
United States
Language:
English

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