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Test-particle simulations in increasingly strong turbulenceQuasi-linear theory supposes that the energy in resonant fluctuations is small compared to that in the mean magnetic field. This is evident in the fact that the zeroth-order particle trajectories are helices about a mean field B(sub o) that is spatially uniform over many correlation lengths. However, in the solar wind it is often the case that the fluctuating part of the field is comparable in magnitude to the mean part. It is generally expected that quasi-linear theory remains viable for particles that are in resonance with a region of the fluctuation spectrum having only small energy density, but even so, care must be taken when comparing simulations to theoretical predictions. We have performed a series of test-particle simulations to explore the evolution of ion distributions in turbulent situations with varying levels of magnetic fluctuations. As delta-B/B(sub o) is increased the distinctions among absolute pitch angle (defined relative to B(sub o)), local pitch angle (defined relative to B(x)), and magnetic moment become important, some of them exhibiting periodic sloshing unrelated to the nonadiabatic processes of interest. Comparing and contrasting the various runs illustrates the phenomena that must be considered when the premise underlying quasi-linear theory are relaxed.
Document ID
19960021430
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
Authors
Pontius, D. H., Jr.
(Delaware Univ. Newark, DE United States)
Gray, P. C.
(Delaware Univ. Newark, DE United States)
Matthaeus, W. H.
(Delaware Univ. Newark, DE United States)
Date Acquired
August 17, 2013
Publication Date
June 30, 1995
Publication Information
Publication: International Solar Wind 8 Conference
Subject Category
Physics (General)
Accession Number
96N24826
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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