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Title: Hybrid simulation of toroidal Alfvén eigenmode on the National Spherical Torus Experiment

Energetic particle modes and Alfvén eigenmodes driven by super-Alfvénic fast ions are routinely observed in neutral beam heated plasmas on the National Spherical Torus eXperiment (NSTX). These modes can significantly impact fast ion transport and thus cause fast ion redistribution or loss. Self-consistent linear simulations of Toroidal Alfvén Eigenmodes (TAEs) in NSTX plasmas have been carried out with the kinetic/magnetohydrodynamic hybrid code M3D-K using experimental plasma parameters and profiles including plasma toroidal rotation. The simulations show that unstable TAEs with n=3,4, or 5 can be excited by the fast ions from neutral beam injection. The simulated mode frequency, mode radial structure, and phase shift are consistent with measurements from a multi-channel microwave reflectometer diagnostic. A sensitivity study on plasma toroidal rotation, safety factor q profile, and initial fast ion distribution is performed. The simulations show that rotation can have a significant destabilizing effect when the rotation is comparable or larger than the experimental level. The mode growth rate is sensitive to q profile and fast ion distribution. Although mode structure and peak position depend somewhat on q profile and plasma rotation, the variation of synthetic reflectometer response is within experimental uncertainty and it is not sensitive enough to see themore » difference clearly.« less
Authors:
 [1] ; ; ; ;  [2] ; ;  [3]
  1. Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)
  2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)
  3. Department of Physics and Astronomy, University of California, Los Angles, California 90095 (United States)
Publication Date:
OSTI Identifier:
22408317
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALFVEN WAVES; BEAM INJECTION; CHARGED-PARTICLE TRANSPORT; COMPUTERIZED SIMULATION; EIGENFREQUENCY; IONS; MICROWAVE RADIATION; NEUTRAL PARTICLES; NSTX DEVICE; PHASE SHIFT; PLASMA; ROTATING PLASMA; SAFETY; SENSITIVITY ANALYSIS