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Department of Nuclear Engineering, Kyoto University, Kyoto, Japan
National Institute for Fusion Science, Toki, Gifu, Japan
S.-I. Itoh, M. Yagi
Research Institute for Applied Mechanics, Kyushu University,
Kasuga, Fukuoka, Japan
Abstract. A theoretical model of internal transport barrier (ITB) is
developed. The transport model based on the self-sustained turbulence theory
of the current-diffusive ballooning mode is extended to include the effects of
E×B rotation shear. Delayed formation of ITB is observed in transport
simulations. The influence of finite gyroradius is also discussed. Simulation
of the current ramp-up experiment successfully described the radial profile of
density, temperature and safety factor. A model of ITB collapse due to
magnetic braiding is proposed. Sudden enhancement of transport triggered by
overlaping of magnetic islands terminates ITB. The possibility of destabilizing
global low-n modes is also discussed.
IAEA 2001
