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Author(s):
Y. Miura, F. Okano, N. Suzuki, M. Mori, K. Hoshino, H. Maeda, T. Takizuka, JFT-2M Group, S.-I. Itoh and K. Itoh
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Title:
Rapid Change of Hydrogen Neutral Energy Distribution at L/H-Transition in JFT-2M H-mode
Date of publication:
Feb. 1992
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Key words:
H-mode, L/H Transition, TOF Neutral Measurement, ELMs, H_ alpha Signal, Energy Distribution Function, Transport Barrier, Main lons
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Abstract:
Rapid changes of the main ion energy distribution at transitions from L-to-H, H-to-L and during ELMs are studied with the time of flight neutral measurement on the JFT-2M tokamak. At the L to H transition, 200-400 mu s prior to the start of H_ alpha drop, an increase of the high energy outflux above an energy of 200eV is observed. An energy of more than 200eV for hydrogen corresponds to the collisionless condition Nu_star i < 1 just inside the separatrix. The change of the energy distribution precedes that of the H_ alpha signal and is also found for ELMs and the H to L transition.
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