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Low-frequency fluctuations in the magnetosheath near the magnetopauseThere are four low-frequency modes which may propagate in a high-beta nearly bi-Maxwellian plasma. These are the magnetosonic, Alfven, ion acoustic, and mirror modes. This manuscript defines a procedure based on linear Vlasov theory for the unique identification of these modes by use of transport ratios, dimensionless ratios of the fluctuating field and plasma quantities. A single parameter, the mode deviation is calculated using the plasma and magnetic field data gathered by the Active Magnetospheric Particle Tracer Explorers/Ion Release Module (AMPTE/IRM) spacecraft to identify the modes observed in the terrestial magnetosheath near the magnetopause. As well as determining the mode which best describes the observed fluctuations, it gives us a measure of whether or not the resulting identification is unique. Using 17 time periods temporally close to a magnetopause crossing, and confining our study to the frequency range from 0.01 to 0.04 Hz, we find that the only clearly identified mode in this frequency range is the mirror mode. Most commonly, the quasi-perpendicular mirror mode (with wave vector k roughly perpendicular to the background magnetic field B(sub zero) is observed. In two events the quasi-parallel mirror mode k parallel B(sub zero) was identified.
Document ID
19950056445
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Denton, Richard E.
(Dartmouth College, Hanover, NH United States)
Gary, S. Peter
(Los Alamos National Laboratory, Los Alamos, NM United States)
Li, Xinlin
(Dartmouth College, Hanover, NH United States)
Anderson, Brian J.
(APL Johns Hopkins Universityry Laurel, MD, United States)
Labelle, James W.
(Dartmouth College, Hanover, NH United States)
Lessard, Marc
(Dartmouth College, Hanover, NH United States)
Date Acquired
August 16, 2013
Publication Date
April 1, 1995
Publication Information
Publication: Journal of Geophysical Research
Volume: 100
Issue: A4
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
95A88044
Funding Number(s)
CONTRACT_GRANT: NAG5-1098
CONTRACT_GRANT: NSF ATM-92-1669
CONTRACT_GRANT: NAGW-1652
Distribution Limits
Public
Copyright
Other

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