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Elemental abundances of flaring solar plasma - Enhanced neon and sulfurElemental abundances of two flares observed with the SMM Flat Crystal Spectrometer are compared and contrasted. The first had a gradual rise and a slow decay, while the second was much more impulsive. Simultaneous spectra of seven bright soft X-ray resonance lines provide information over a broad temperature range and are available throughout both flares, making these events unique in the SMM data base. For the first flare, the plasma seemed to be characterized by coronal abundances but, for the second, the plasma composition could not be coronal, photospheric, or a linear combination of both. A good differential emission measure fit required enhanced neon such that Ne/O = 0.32 +/- 0.02, a value which is inconsistent with the current models of coronal abundances based on the elemental first-ionization potential. Similar values of enhanced neon are found for flaring plasma observed by the SMM gamma-ray spectrometer, in (He-3)-rich solar energetic particle events, and in the decay phase of several long duration soft X-ray events. Sulfur is also enhanced in the impulsive flare, but not as dramatically as neon. These events are compared with two models which attempt to explain the enhanced values of neon and sulfur.
Document ID
19930051608
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Schmelz, J. T.
(NASA Goddard Space Flight Center Greenbelt, MD; Rhodes College, Memphis, TN, United States)
Date Acquired
August 16, 2013
Publication Date
May 1, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 408
Issue: 1
ISSN: 0004-637X
Subject Category
Solar Physics
Accession Number
93A35605
Funding Number(s)
CONTRACT_GRANT: NAT0-910497
CONTRACT_GRANT: NAS5-30431
Distribution Limits
Public
Copyright
Other

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