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The whistler heat flux instability: Threshold conditions in the solar windSolar wind electrons are observed often to consist of two components: a core and a halo. The anisotropics and relative average speeds of these components correspond to a heat flux that has the potential to excite several different electromagetic instabilities; wave-particle scattering by the resulting enhanced fluctuations can limit this heat flux. This manuscript describes theoretical studies using the linear Vlasco dispersion equation for drifting bi-Maxwellian component distributions in a homogeneous plasma to examine the threshold of the whistler heat flux instability. Expressions for this threshold are obtained from two different parametric baselines: a local model that yields scalings as functions of local dimensionless plasma paramaters, and a global model based on average electron properties observed during the in-eliptic phase of the Ulysses mission. The latter model yields an expression for the heat flux at threshold of the whistler instability as a function of helisopheric radius that scales in the same way as the average heat flux observed form Ulysses and that provides an approximate upper bound for that same quantity. This theoretical scaling is combined with the observational results to yield a semi-empirical closure relation for the average electron heat flux in the solar wind between 1 and 5 AU.
Document ID
19950048192
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Gary, S. Peter
(Los Alamos National Laboratory, Los Alamos, NM United States)
Scime, Earl E.
(Los Alamos National Laboratory, Los Alamos, NM United States)
Phillips, John L.
(Los Alamos National Laboratory, Los Alamos, NM United States)
Feldman, William C.
(Los Alamos National Laboratory, Los Alamos, NM United States)
Date Acquired
August 16, 2013
Publication Date
December 1, 1994
Publication Information
Publication: Journal of Geophysical Research
Volume: 99
Issue: A12
ISSN: 0148-0227
Subject Category
Solar Physics
Accession Number
95A79791
Distribution Limits
Public
Copyright
Other

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