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Title: Collisional dependence of Alfvén mode saturation in tokamaks

Saturation of Alfvén modes driven unstable by a distribution of high energy particles as a function of collisionality is investigated with a guiding center code, using numerical eigenfunctions produced by linear theory and numerical high energy particle distributions. The most important resonance is found and it is shown that when the resonance domain is bounded, not allowing particles to collisionlessly escape, the saturation amplitude is given by the balance of the resonance mixing time with the time for nearby particles to collisionally diffuse across the resonance width. Finally, saturation amplitudes are in agreement with theoretical predictions as long as the mode amplitude is not so large that it produces stochastic loss from the resonance domain.
 [1] ;  [2]
  1. Zhejiang Univ., Hangzhou (People's Republic of China)
  2. Princeton Univ., Princeton, NJ (United States). Plasma Physics Lab.
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0741-3335; TRN: US1701331
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Plasma Physics and Controlled Fusion
Additional Journal Information:
Journal Volume: 58; Journal Issue: 12; Journal ID: ISSN 0741-3335
IOP Science
Research Org:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org:
Country of Publication:
United States
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Alfvén modes; saturation; collisions; tokamaks