-
Author(s):
K. Toi, Y. Hamada, K. Kawahata, T. Watari, A. Ando, K. Ida, S. Morita, R. Kumazawa, Y. Oka, K. Masai, M. Sakamoto, K. Adati, R. Akiyama, S. Hidekuma, S. Hirokura, O. Kaneko, A. Karita, T. Kawamoto, Y. Kawasumi, M. Kojima, T. Kuroda, K. Narihara, Y. Ogawa, K. Ohkubo, S. Okajima, T. Ozaki, M. Sasao, K. Sato, K.N. Sato, T. Seki, F. Shimpo, H. Takahashi, S. Tanahashi, Y. Taniguchi and T. Tsuzuki
-
Title:
Study of Limiter H- and IOC- Modes by Control of Edge Magnetic Shear and Gas Puffing in the JIPP T-IIU Tokamak
Date of publication:
Sep. 1990
-
Key words:
Limiter H-Mode, L-H Transition, Edge Magnetic Shear, Edge Toroidal Current Density, Edge Localized Modes, Limiter lOC-Mode, Gas Puff Control, Density Fluctuations
-
Abstract:
Two types of improved confinement regimes, H-mode and lOC( improved ohmic confinement)-mode, are studied in circular-limiter plasmas on JIPP T-IIU. When the rapid ramp-down of plasma current ( CRD ) is employed during auxiliary heating, the threshold heating power required for the L-H transition is reduced by 30-50 %, compared with that in the case without CRD. This is interpreted to be due to enhancement of the global magnetic shear near the plasma edge by CRD. This model based on edge magnetic shear is also applicable to the limiter H-mode obtained without CRD by high heating power. In the limiter configuration, improved confinement regime, lOC-mode, is obtained in ohmically heated high density plasmas by gas puff control. This improvement may be attributed to reduction of anomalous transport, since radiation loss has only minor effect.
-
|
