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Ground-based studies of ionospheric convection associated with substorm expansionThe instantaneous patterns of electric fields and currents in the high-latitude ionosphere are deduced by combining satellite and radar measurements of the ionospheric drift velocity, along with ground-based magnetometer observations for October 25, 1981. The period under study was characterized by a relatively stable southward interplanetary magnetic field (IMF), so that the obtained electric field patterns do reflect, in general, the state of sustained and enhanced plasma convection in the magnetosphere. During one of the satellite passes, however, an intense westward electrojet caused by a substorm intruded into the satellite (DE2) and radar (Chatanika, Alaska) field of view in the premidnight sector, providing a unique opportunity to differentiate the enhanced convection and substorm expansion fields. The distributions of the calculated electric potential for the expansion and maximum phases of the substorm show the first clear evidence of the coexistence of two physically different systems in the global convection pattern. The changes in the convection pattern during the substorm indicate that the large-scale potential distributions are indeed of general two-cell patterns representing the southward IMF status, but the night-morning cell has two positive peaks, one in the midnight sector and the other in the late morning hours, corresponding to the substorm expansion and the convection enhancement, respectively.
Document ID
19950045388
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kamide, Y.
(Nagoya Univ. Toyokawa, Japan)
Richmond, A. D.
(High Altitude Observatory, NCAR, Boulder, CO United States)
Emery, B. A.
(High Altitude Observatory, NCAR, Boulder, CO United States)
Hutchins, C. F.
(High Altitude Observatory, NCAR, Boulder, CO United States)
Ahn, B.-H.
(High Altitude Observatory, NCAR, Boulder, CO United States)
De La Beaujardiere, O.
(Stanford Research Inst. International, Menlo Park, CA United States)
Foster, J. C.
(Haystack Observatory, Massachusetts Inst. of Tech., Cambridge, MA United States)
Heelis, R. A.
(Texas Univ. at Dallas, Richardson, TX, United States)
Kroehl, H. W.
(National Geophysical Data Center NOAA, Boulder, CO, United States)
Rich, F. J.
(Air Force Geophysics Lab. Hanscom AF Base, MA, United States)
Date Acquired
August 16, 2013
Publication Date
October 1, 1994
Publication Information
Publication: Journal of Geophysical Research
Volume: 99
Issue: A10
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
95A76987
Funding Number(s)
CONTRACT_GRANT: NASA ORDER W-17384
CONTRACT_GRANT: F49620-92-C-0011
Distribution Limits
Public
Copyright
Other

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