Toroidal Symmetry of the Geodesic Acoustic Mode Zonal Flow in a Tokamak Plasma
- Southwestern Institute of Physics, P.O. Box 432, Chengdu (China)
- Department of Modern Physics, University of Science and Technology of China, Hefei (China)
The toroidal symmetry of the geodesic acoustic mode (GAM) zonal flows is identified with toroidally distributed three step Langmuir probes at the edge of the HuanLiuqi-2A (commonly referred to as HL-2A) tokamak plasmas for the first time. High coherence of both the GAM and the ambient turbulence for the toroidally displaced measurements along a magnetic field line is observed, in contrast with the high coherence of the GAM but low coherence of the ambient turbulence when the toroidally displaced measurements are not along the same field line. The radial and poloidal features of the flows are also simultaneously determined. The nonlinear three wave coupling between the high frequency turbulent fluctuations and the flows is demonstrated to be a plausible formation mechanism of the flows.
- OSTI ID:
- 20775295
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 25 Vol. 96; ISSN 0031-9007; ISSN PRLTAO
- Country of Publication:
- United States
- Language:
- English
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