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Title: Fishbone activity in experimental advanced superconducting tokamak neutral beam injection plasma

Repetitive fishbones near the trapped ion procession frequency were observed for the first time in the neutral beam injection high confinement plasmas in Experimental Advanced Superconducting Tokamak (EAST) tokamak, and diagnosed using a solid-state neutral particle analyzer based on a compact silicon photodiode together with an upgraded high spatial-temporal-resolution multi-arrays soft X-ray (SX) system. This 1/1 typical internal kink mode propagates in the ion-diamagnetism direction with a rotation speed faster than the bulk plasma in the plasma frame. From the SX measurements, this mode frequency is typical of chirping down and the energetic particle effect related to the twisting mode structure. This ion fishbone was found able to trigger a multiple core sawtooth crashes with edge-2/1 sideband modes, as well as to lead to a transition from fishbone to long lived saturated kink mode to fishbone. Furthermore, using SX tomography, a correlation between mode amplitude and mode frequency was found. Finally, a phenomenological prey–predator model was found to reproduce the fishbone nonlinear process well.
Authors:
; ; ; ; ; ; ;  [1] ;  [2]
  1. Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)
  2. Department of Physics and Astronomy, University of California, Irvine, California 92697-4575 (United States)
Publication Date:
OSTI Identifier:
22489931
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 12; 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; BEAM INJECTION; DIAMAGNETISM; HT-7U TOKAMAK; IONS; NEUTRAL PARTICLE ANALYZERS; NONLINEAR PROBLEMS; PLASMA; PLASMA CONFINEMENT; PLASMA INSTABILITY; ROTATING PLASMA; SAWTOOTH OSCILLATIONS; SILICON; SOFT X RADIATION; SPATIAL RESOLUTION; TIME RESOLUTION; TOMOGRAPHY; TRAPPING