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Title: Flux-driven algebraic damping of diocotron modes

Recent experiments with pure electron plasmas in a Malmberg-Penning trap have observed the algebraic damping of m = 1 and m = 2 diocotron modes. Transport due to small field asymmetries produces a low density halo of electrons moving radially outward from the plasma core, and the mode damping begins when the halo reaches the resonant radius R{sub m}, where there is a matching of ω{sub m} = mω{sub E} (R{sub m}) for the mode frequency ω{sub m} and E × B-drift rotation frequency ω{sub E}. The damping rate is proportional to the flux of halo particles through the resonant layer. The damping is related to, but distinct from, spatial Landau damping, in which a linear wave-particle resonance produces exponential damping. This new mechanism of damping is due to transfer of canonical angular momentum from the mode to halo particles, as they are swept around the “cat’s eye” orbits of the resonant wave-particle interaction. This paper provides a simple derivation of the time dependence of the mode amplitudes.
Authors:
;  [1]
  1. University of California, San Diego, CA 92093 (United States)
Publication Date:
OSTI Identifier:
22490688
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1668; Journal Issue: 1; Conference: 11. international workshop on non-neutral plasmas, Takamatsu (Japan), 1-4 Dec 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLITUDES; ANGULAR MOMENTUM; ASYMMETRY; ELECTRONS; LANDAU DAMPING; LAYERS; ORBITS; PLASMA; PLASMA DRIFT; RESONANCE; ROTATION; TIME DEPENDENCE; TRAPS