Observation of Nonlinear Coupling between Small-Poloidal Wave-Number Potential Fluctuations and Turbulent Potential Fluctuations in Ohmically Heated Plasmas in the JFT-2M Tokamak
- 23 August 2005
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 95 (9), 095002
- https://doi.org/10.1103/physrevlett.95.095002
Abstract
Two types of electrostatic modes with small-poloidal wave numbers ( and ) are observed in the edge region of Ohmically heated plasmas in the JFT-2M tokamak. The envelope of the higher frequency coherent mode is modulated at the frequency of the lower frequency mode. A bispectral analysis revealed that a significant nonlinear coupling among the two types of fluctuations and the broadband background turbulent potential fluctuations occurs inside the last closed magnetic flux surface, suggesting that a nonlinear process such as the parametric-modulational instability is involved.
Keywords
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