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Analytic slowing-down distributions as modified by turbulent transport

Part of: PLA 17th European Fusion Theory Conference

Published online by Cambridge University Press:  13 November 2018

G. J. Wilkie Open the ORCID record for G. J. Wilkie [Opens in a new window]
G. J. Wilkie*
Affiliation:
Department of Physics, Chalmers University of Technology, Gothenburg 41258, Sweden
*
†Email address for correspondence: wilkie@chalmers.se
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Abstract

The effect of electrostatic microturbulence on fast particles rapidly decreases at high energy, but can be significant at moderate energy. Previous studies found that, in addition to changes in the energetic particle density, this results in non-trivial changes to the equilibrium velocity distribution. These effects have implications for plasma heating and the stability of Alfvén eigenmodes, but make multiscale simulations much more difficult without further approximations. Here, several related analytic model distribution functions are derived from first principles. A single dimensionless parameter characterizes the relative strength of turbulence relative to collisions, and this parameter appears as an exponent in the model distribution functions. Even the most simple of these models reproduces key features of the numerical phase-space transport solution and provides a useful a priori heuristic for determining how strong the effect of turbulence is on the redistribution of energetic particles in toroidal plasmas.

Keywords

fusion plasmaplasma confinementplasma heating
Type
Research Article
Information
Journal of Plasma Physics , Volume 84 , Issue 6 , December 2018 , 745840601
Copyright
© Cambridge University Press 2018 

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