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Idomura, Yasuhiro
no journal, ,
no abstracts in English
Suzuki, Takahiro; JT-60 Team
no journal, ,
no abstracts in English
Yoshida, Maiko
no journal, ,
The momentum transport is one of the crucial parameter for determination of the rotation profile. Therefore, it is the critical importance to understand the properties of the momentum transport coefficients for the prediction of the rotation in next step devices. In some devices, many interesting results are reported using perturebative experiments. The purpose of this study is to understand the characteristics of momentum transport coefficients including diffusive and non-diffusive terms by multi-machine experiments over a wide range of magnetic configurations. A database of multi-machine analysis from plasma and engineering parameters scans will be constructed. We expand on existing data set with different values of non-dimensional parameters so as to establish a modeling/scaling and to predict rotation profile in ITER.
Yoshida, Maiko
no journal, ,
The momentum transport coefficients are one of the most crucial parameters for the determination of the toroidal rotation profile. Also the ratio of the momentum transport diffusivity and the thermal diffusivity, and the ratio of the convection velocity and the momentum transport diffusivity provide key information to predict the momentum transport levels such as neoclassical and turbulence levels. The ratio of the momentum transport diffusivity and the thermal diffusivity increases with increasing ion temperature and decreases with increasing electron density. This tendency is almost the same even in the different radial positions. The ratio of the convection velocity and the momentum transport diffusivity increases with electron temperature. The same correlation is observed radially.
Takenaga, Hidenobu; JT-60 Team
no journal, ,
The results on the multi-machine joint experiments of "transport dependence of high performance operation on E
B shear and momentum" performed in ITPA are summarized. In weak shear plasmas, highest confinement and most reduced transport in the internal transport barrier (ITB) region were obtained with co-rotation. The direction of the rotation seemed to be important for achievement of high confinement and reduced transport rather than EB shear. However, the effects of the rotation was relatively small in weak shear plasmas. On the other hand, in reversed shear plasmas, confinement and rotation were strongly linked with each other. When the transport significantly decreased in the ITB region, a notch structure was formed in the toroidal rotation profile and strong EB shear was produced. When momentum was injected to weaken the notch structure, the transport was enhanced. In reversed shear plasmas, disruption and collapse were avoided by ITB control using momentum input.
Hayashi, Nobuhiko; Honda, Mitsuru
no journal, ,
no abstracts in English
Nakamura, Yukiharu*; Miyamoto, Seiji; Sugie, Tatsuo; Kusama, Yoshinori; Yoshino, Ryuji
no journal, ,
The ITER termination scenario from 15 MA to 1.5 MA (500 s 
t 
700 s) [A.A. Kavin 
, Progress report of plasma startup and termination, ITER_D_2F55U5 (2008)] was reviewed by self-consistent simulations with the TSC code, comprised of newly developed D-T fuelling and pumping-out system. The dynamics of a forced H- to L-mode transition, 
reduction in the plasma density while building-up of the in-vessel neutral gas, disappearance of the edge BS current and consequent jump in the internal inductance, were investigated to assess the performance of the ITER pump-out system. It was newly demonstrated that the forced H-L mode transition may trigger a radiation collapse, consequently terminating the discharge even in magnetic divertor configuration, if the effective pumping speed is insufficient or if the wall retention of the neutral particle remains saturated. In order to avoid the radiation collapse during plasma termination, off-axis heating and current drive with 170 GHz O-mode EC wave was utilized and shown to be effective.