Energetic-particle abundances in impulsive solar flare events

Details Energetic-particle abundances in impulsive solar flare events Energetic-particle abundances in impulsive solar flare events

Feb 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apjs...90..649r&link_type=abstract

Astrophysical Journal Supplement Series (ISSN 0067-0049), vol. 90, no. 2, p. 649-667

Astronomy and Astrophysics

Astrophysics

154

Abundance, Energetic Particles, Isotopic Enrichment, Particle Emission, Solar Flares, Chemical Elements, Electron Energy, Heavy Ions, International Sun Earth Explorer 3, Spectral Signatures

Scientific paper

We report on the abundances of energetic particles from impulsive solar flares, including those from a survey of 228 He-3 rich events, with He-3/He-4 is greater than 0.1, observed by the International Sun Earth Explorer (ISEE) 3 spacecraft from 1978 August through 1991 April. The rate of occurrence of these events corresponds to approximately 1000 events/yr on the solar disk at solar maximum. Thus the resonant plasma processes that enhance He-3 and heavy elements are a common occurrence in impulsive solar flares. To supply the observed fluence of He-3 in large events, the acceleration must be highly efficient and the source region must be relatively deep in the atmosphere at a density of more than 1010 atoms/cu cm. He-3/He-4 may decrease in very large impulsive events because of depletion of He-3 in the source region. The event-to-event variations in He-3/He-4, H/He-4, e/p, and Fe/C are uncorrelated in our event sample. Abundances of the elements show a pattern in which, relative to coronal composition, He-4, C, N, and O have normal abundance ratios, while Ne, Mg, and Si are enhanced by a factor approximately 2.5 and Fe by a factor approximately 7. This pattern suggests that elements are accelerated from a region of the corona with an electron temperature of approximately 3-5 MK, where elements in the first group are fully ionized (Q/A = 0.5), those in the second group have two orbital electrons (Q/A approximately 0.43), and Fe has Q/A approximately 0.28. Ions with the same gyrofrequency absorb waves of that frequency and are similarly accelerated and enhanced. Further stripping may occur after acceleration as the ions begin to interact with the streaming electrons that generated the plasma waves.

Affiliated with

Also associated with

No associations

Rating

Energetic-particle abundances in impulsive solar flare events does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Energetic-particle abundances in impulsive solar flare events, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Energetic-particle abundances in impulsive solar flare events will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1014791