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Author(s):
S. Murakami, N. Nakajima, M. Okamoto and J. Nuhrenberg
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Title:
Effect of Energetic Ion Loss on ICRF Heating Efficiency and Energy Confinement Time in Heliotrons
Date of publication:
June 1999
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Key words:
ICRF heating, energetic ion, orbit loss, global energy confinement, heliotron
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Abstract:
ICRF heating efficiency and the global energy confinement time during ICRF heating are investigated including the effect of energetic ion loss in heliotrons. The approximate formula of ICRF heating efficiency is derived using the results based on Monte Carlo simulations. The global energy confinement time including energetic ion effect can be expressed in terms of ICRF heating power, plasma density, and magnetic field strength in heliotrons. Our results in the CHS plasma show the systematic decrement of the global energy confinement time due to the energetic ion loss from the assumed energy confinement scaling law, which is consistent with the experimental observations. Also we apply our model to the ICRF minority heating in the LHD plasma in two cases of typical magnetic configurations. The clear increment of the global energy confinement time due to the stored energy of energetic tail ions is obtained in the "orbit improved" configuration, while the decrement is observed in the "standard" configuration.
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