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Observational test of shock drift and Fermi acceleration on a seed particle population upstream of earth's bow shockThe efficiency of proposed shock acceleration mechanisms as they operate at the bow shock in the presence of a seed energetic particle population was examined using data from simultaneous observations of energetic solar-origin protons, carried out by the IMP 7 and 8 spacecraft in the vicinity of the quasi-parallel (dawn) and quasi-perpendicular (dusk) regions of the earth's bow shock, respectively. The results of observations (which include acceleration effects in the intensities of the energetic protons with energies as high as 4 MeV observed at the vicinity of the dusk bow shock, but no evidence for any particle acceleration at the energy equal to or above 50 keV at the dawn side of the bow shock) indicate that the acceleration of a seed particle population occurs only at the quasi-perpendicular bow shock through shock drift acceleration and that the major source of observed upstream ion populations is the leakage of magnetospheric ions of energies not less than 50 keV, rather than in situ acceleration.
Document ID
19880052783
Document Type
Reprint (Version printed in journal)
Authors
Anagnostopoulos, G. C. (Thrace Univ. Xanthe, Greece)
Sarris, E. T. (Thrace, University Xanthi, Greece)
Krimigis, S. M. (Johns Hopkins University Laurel, MD, United States)
Date Acquired
August 13, 2013
Publication Date
June 1, 1988
Publication Information
Publication: Journal of Geophysical Research
Volume: 93
ISSN: 0148-0227
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSF ATM-86-11354
CONTRACT_GRANT: N00039-87-C-5301
CONTRACT_GRANT: NASA TASK I
Distribution Limits
Public
Copyright
Other