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This content will become publicly available on January 23, 2019

Title: Stochastic effects on phase-space holes and clumps in kinetic systems near marginal stability

The creation and subsequent evolution of marginally-unstable modes have been observed in a wide range of fusion devices. This behaviour has been successfully explained, for a single frequency shifting mode, in terms of phase-space structures known as a 'hole' and 'clump'. Here in this paper, we introduce stochasticity into a 1D kinetic model, affecting the formation and evolution of resonant modes in the system. We find that noise in the fast particle distribution or electric field leads to a shift in the asymptotic behaviour of a chirping resonant mode; this noise heuristically maps onto radial microturbulence via canonical toroidal momentum scattering, affecting hole and clump formation. While the mechanism allowing for the formation of the hole and clump is coherent, the lifetime of a hole and clump is shown to be highly sensitive to initial conditions, affecting the temporal profile of a single bursting event in mode amplitude.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [1] ;  [3] ;  [1]
  1. Univ. of York (United Kingdom). York Plasma Inst., Dept. of Physics
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of Sao Paulo (Brazil). Inst. of Physics
  3. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Grant/Contract Number:
AC02-09CH11466; EP/K000225; EP/L01663X; 2012/22830-2
Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Name: Nuclear Fusion; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Research Org:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org:
USDOE; So Paulo Research Foundation
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; stochasticity; turbulence; fast ions; hole and clump; nonlinear dynamics; mode chirping; kinetic instabilities
OSTI Identifier:
1425202