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Nonlinear astrophysical Alfven waves - Onset and outcome of the modulational instabilityThe nonlinear development of Alfven waves is numerically studied, with applications to Alfven waves in astrophysical plasmas. It is found that amplitude-modulated Alfven wave packets undergo a collapse instability in which the wave packets become more intense and of smaller spatial extent. The wave packet steepening is eventually halted in a process most aptly described as soliton formation. A simple analytic model based on the method of characteristics can account for many of the results of the numerical calculations. The instability probably cannot prevent particle pitch angle isotropization due to self-generated Alfven waves. Nonlinear effects of the collapse may modify the process by which energetic electrons are reaccelerated by plasma turbulence. The model calculations can semiquantitatively account for properties of shock-associated Alfven waves in the solar system.
Document ID
19860035548
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Spangler, S. R.
(Iowa, University Iowa City, United States)
Date Acquired
August 12, 2013
Publication Date
December 1, 1985
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 299
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
86A20286
Funding Number(s)
CONTRACT_GRANT: NAGW-386
CONTRACT_GRANT: NSF AST-82-17714
Distribution Limits
Public
Copyright
Other

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