Open AccessModification of Particle Distributions by MHD Instabilities II
Author(s) -
R. B. White
Publication year - 2011
Language(s) - English
Resource type - Reports
DOI - 10.2172/1007221
Subject(s) - magnetohydrodynamic drive , magnetohydrodynamics , amplitude , flattening , particle (ecology) , physics , phase space , plasma , mechanics , phase (matter) , computational physics , statistical physics , nuclear physics , optics , thermodynamics , quantum mechanics , oceanography , astronomy , geology
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