(EX/2-2) Measurement and analysis of the fluctuations and poloidal flow on JFT-2M tokamak

K. Hoshino1), T. Ido2), Y. Nagashima3), K. Shinohara1), H. Ogawa1), K. Kamiya1), H. Kawashima1), K. Tsuzuki1), Y. Kusama1), K. Ohasa1), K. Uehara1), S. Kasai1), Y. Hamada2), A. Ejiri4), Y. Takase4), JFT-2M Group1)
1) Japan Atomic Energy Agency, Naka, Japan
2) National Institute for Fusion Science, Toki, Japan
3) Kyushu Univ., Fukuoka, Japan
4) The Univ. Tokyo, Tokyo, Japan

Abstract.  The potential/density fluctuations and E×B poloidal flow inside of the separatrix were measured in the JFT-2M tokamak using heavy ion beam probe (HIBP),reciprocate probe and microwave reflectometer. The strength of the three-wave interaction between the background turbulence and the geodesic acoustic mode (GAM) was obtained by estimating the bispectrum function, and its convergence property was clarified for the first time. The GAM disappears in the H-mode, instead negative DC electric field dominates. The observed DC poloidal flow at the edge transport barrier(ETB) of ECH H-mode is found to be typically 20∼30 times larger than the oscillating (15 kHz) poloidal flow by the GAM in the L-mode.

Full paper and slides available (PDF)