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Y. Hamada, T. Ido, K. Kamiya, A. Nishizawa,
Y. Kawasumi
National Institute for Fusion Science, Toki, 509-5292, Japan
Y. Miura, and JFT-2M Team
Japan Atomic Energy Research Institute, Ibaraki, 319-1195, Japan
Abstract. The fast potential change at H-mode transition was measured for
the first time by a 500 keV heavy ion beam probe installed on the JFT-2M
tokamak. It is found that in an ordinary sawtooth-triggered L/H-transition,
the fast positive potential change is observed near the separatrix in
coincidence with the fast
D
rise and the fast density
change. The potential goes down at the fall of
D. The
structure of the radial electric field about 30 msec after L/H transition
agrees with the previous results determined by the poloidal, toroidal rotation
speed and the pressure gradient.
IAEA 2001
