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Pitch angle distributions of low-energy ions in the near-earth magnetosphereEnergetic ion composition data acquired by satellite have been used to study the characteristics of ion pitch angle distributions in the near-earth magnetosphere. Both H(+) and O(+) ions below 1 keV were most frequently observed to have bidirectional field-aligned or conical pitch angle distributions inside L of about 6, with the exception of highly trapped H(+) very near the magnetic equator. The occurrence probability distributions of counterstreaming ions (CSI) and bidirectional conics in magnetic local time and L shell space suggest that the observed CSI were formed near the postmidnight sector and subsequently drifted eastward, and that ions close to the field-aligned direction were probably lost due to charge exchange with atmospheric hydrogen in the course of their eastward drift. In the prenoon sector, conical distributions dominated. Bidirectional ions were vary rarely observed in the afternoon sector, presumably because their drift paths crossed the magnetopause into the dayside magnetosheath.
Document ID
19880033117
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Sagawa, E.
(Herzberg Inst. of Astrophysics Ottawa Ontario, Canada)
Yau, A. W.
(Herzberg Inst. of Astrophysics Ottawa Ontario, Canada)
Whalen, B. A.
(National Research Council of Canada Herzberg Institute of Astrophysics, Ottawa, United States)
Peterson, W. K.
(Lockheed Research Laboratories Palo Alto, CA, United States)
Date Acquired
August 13, 2013
Publication Date
November 1, 1987
Publication Information
Publication: Journal of Geophysical Research
Volume: 92
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
88A20344
Funding Number(s)
CONTRACT_GRANT: NAS5-28710
Distribution Limits
Public
Copyright
Other

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