Observation of Nonlinear Coupling between Small-Poloidal Wave-Number Potential Fluctuations and Turbulent Potential Fluctuations in Ohmically Heated Plasmas in the JFT-2M Tokamak

Journal Article · Fri Aug 26 04:00:00 EDT 2005 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.95.095002· OSTI ID:20699374

Nagashima, Y; Ejiri, A; Takase, Y ^[1]; Hoshino, K; Shinohara, K; Tsuzuki, K; Uehara, K; Kawashima, H; Ogawa, H; Kusama, Y; Miura, Y ^[2]; Ido, T ^[3]

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1. University of Tokyo, Tokyo 113-0033 (Japan)
2. Japan Atomic Energy Research Institute, Ibaraki 311-0193 (Japan)
3. National Institute for Fusion Science, Gifu 509-5292 (Japan)

Two types of electrostatic modes with small-poloidal wave numbers ({approx}1 and 10-15 kHz) 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.

• OSTI ID: 20699374
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 9 Vol. 95; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
FLUCTUATIONS
JFT-2M TOKAMAK
KHZ RANGE 01-100
MAGNETIC FLUX
NONLINEAR PROBLEMS
PLASMA
PLASMA CONFINEMENT
PLASMA HEATING
PLASMA INSTABILITY
PLASMA WAVES
POTENTIALS