Experimental Observation of Magnetic Fluctuations in NBI Heated Plasmas in CHS

概要

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The magnetic fluctuations with the frequency f≤100 kHz in NBI heated plasmas have been investigated in the Compact Helical System (CHS). The observed coherent fluctuations are identified as global modes with m≤4, n≤3. The dependences of these modes on the magnetic configuration and the plasma beta are well interpreted phenomenologically by the theoretical models of the resistive and the ideal inter-change modes. Both these modes and the incoherent fluctuations increase with the beta value <β_<dia>>, however, saturate when <β_<dia>> reaches about 1%. The present accessible limit of <β_<dia>>=2.0% is determined by the confinement of which a key mechnism is not the instabilities investigated here. The nonlinear saturation mechanism must be clarified, because the change of the fluctuation amplitude can not be explained from the model that the saturation level is proportional to the linear growth rate of an instability.
社団法人日本物理学会の論文
1994-12-15