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Magnetosheath-ionospheric plasma interactions in the cusp/cleft. 1: Observations of modulated injections and upwelling ion fluxesIn situ observations of the cusp/cleft are important as they allow a direct investigation of coupling solar wind energy to the ionosphere, plus they provide an opportunity for the remote sensing of the magnetopause. High time resolution observations from Dynamic Explorer 1 are used to investigate these processes. It is shown that in the spacecraft frame the injection is modulated or pulsating with a period of approximately 18-30 s with the injection duration possibly being as short as 6 s. This modulation indicates that there may be fast time scale and/or short scale length processes modulating the injection of the magnetosheath plasma across the magnetopause. In addition, the pulsating injection is seen to modulate the outflow of upwelling ionospheric ions to the magnetosphere. These upwelling ions are seen prior to the magnetosheath ion injection and therefore are not directly created by the injection. During the injection itself, the intensity of the upwelling ions is seen to dramatically decrease but their average energy increases. At end of the magnetosheath injections, the intensity of the upwelling ion flux is seen to increase to levels comparable to levels prior to the magnetosheath injection. On two occasions during the encounter, the particle fluxes are sufficiently high that enhanced downward flows of perpendicularly heated ions, of presumably ionospheric origin, are observed in association with a reduction in the intensity of the upwelling ions. These observations are probably the first detection of downward conics and suggest that there is momentum transfer between the magnetosheath and ionospheric ions. This momentum transfer eventually leads to an enhanced outflow of heated ionospheric plasma where their energy has been raised from a few tens of eV to a few hundred eV.
Document ID
19950059017
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Winglee, R. M.
(Univ. of Washington, Seattle, WA United States)
Menietti, J. D.
(Univ. of Iowa, Iowa City, IA United States)
Peterson, W. K.
(Space Science Lab. Palo Alto, CA, United States)
Burch, J. L.
(Southwest Research Inst. San Antonio, United States)
Waite, J. H., Jr.
(Southwest Research Inst. San Antonio, United States)
Giles, B.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 16, 2013
Publication Date
November 1, 1993
Publication Information
Publication: Journal of Geophysical Research
Volume: 98
Issue: A11
ISSN: 0148-0227
Subject Category
Astrophysics
Accession Number
95A90616
Funding Number(s)
CONTRACT_GRANT: NAGW-2412
CONTRACT_GRANT: NAG5-1554
CONTRACT_GRANT: NAGW-1936
CONTRACT_GRANT: NSF ATM-92-96075
CONTRACT_GRANT: NAGW-2471
CONTRACT_GRANT: NAS5-3302
Distribution Limits
Public
Copyright
Other

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