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Particle acceleration and sources in the November 1997 solar energetic particle events
Author(s) -
Mason G. M.,
Cohen C. M. S.,
Cummings A. C.,
Dwyer J. R.,
Gold R. E.,
Krimigis S. M.,
Leske R. A.,
Mazur J. E.,
Mewaldt R. A.,
Möbius E.,
Popecki M.,
Stone E. C.,
von Rosenvinge T. T.,
Wiedenbeck M. E.
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1998gl900235
Subject(s) - physics , particle acceleration , event (particle physics) , solar energetic particles , spectral line , particle (ecology) , spacecraft , acceleration , solar wind , nuclear physics , astrophysics , computational physics , atomic physics , coronal mass ejection , astronomy , electron , plasma , geology , oceanography , classical mechanics
We report studies of two large solar energetic particle (SEP) events on Nov. 4 and 6, 1997 that were observed using advanced energetic particle detectors on the ACE and the Wind spacecraft. Both events showed enriched Fe/O, and had a ∼1 MeV/n ³He/ 4 He ratio = 2.1 × 10 −3 , 4 times the coronal value. The Nov. 6 event had exceptionally hard spectra, with much higher intensities of high energy (10s of MeV) particles than the Nov. 4 event, yet below 1 MeV/n the intensities in the Nov. 6 event were lower than for Nov. 4. Strong, complex temporal variations observed for ∼120 keV Fe/O contrasted with only gradual changes of this ratio at ∼25 MeV/n. A spectral break was observed in the Nov. 6 event, wherein below a few MeV/n the spectra became harder. Taken together, these observations point to different seed and acceleration mechanisms dominating at low and high energies in these events.