Modification of Particle Distributions by MHD Instabilities II
Authors: Roscoe B. White
Abstract:
The modification of particle distributions by low amplitude magnetohydrodynamic modes is
an important topic for magnetically confined plasmas. Low amplitude modes are known to be
capable of producing significant modification of injected neutral beam profiles, and the same can
be expected in burning plasmas for the alpha particle distributions. Flattening of a distribution in
an island due to phase mixing and portions of phase space becoming stochastic lead to modification
of the particle distribution, a process extremely rapid in the time scale of an experiment but still
very long compared to the time scale of guiding center simulations. Large amplitude modes can
cause profile avalanche and particle loss. Thus it is very valuable to be able to predict the temporal
evolution of a particle distribution produced by a given spectrum of magnetohydrodynamic modes.
In this paper we further develop and investigate the use of a new method of determining domains
of phase space in which good KAM surfaces do not exist and use this method to examine a well
documented case of profile modification by instabilities.
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Submitted to: Plasma Physics Controlled Fusion (February 2011)
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Download PPPL-4605 (pdf 6.0 MB 23 pp)
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