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Oikawa, Toshihiro
no journal, ,
Electron cyclotron current drive (ECCD) at a magnetic island is planned in ITER to stabilize neoclassical tearing modes (NTMs). EC injection within a rotating island is in scope since it is shown theoretically that modulated ECCD application only inside the island is more effective for NTM stabilization than continuous ECCD that is deposited both inside and outside the island. Thus, modulation frequency required from physics aspects of plasma rotation and NTMs has to be fed back to the EC system design. Based on a modulation frequency evaluated from a plasma rotation profile induced by neutral beam torque input, we will discuss at the meeting uncertainty in the predicted rotation, effectiveness of the modulation operation and so on.
plasmasMatsunaga, Go; Sakamoto, Yoshiteru; Aiba, Nobuyuki; Takechi, Manabu; Suzuki, Takahiro; Asakura, Nobuyuki; Isayama, Akihiko; Oyama, Naoyuki; Takenaga, Hidenobu; Kamada, Yutaka; et al.
no journal, ,
no abstracts in English
Aiba, Nobuyuki; Hayashi, Nobuhiko; Takizuka, Tomonori; Tokuda, Shinji; Ozeki, Takahisa
no journal, ,
The effects of the equilibrium properties on the structure of the edge MHD modes in tokamaks are investigated numerically. In particular, we focus on the effects of the plasma shape and the pressure profile inside the top of the pedestal. As the results of numerical analyses, we find that the structure of the unstable MHD mode expands to the plasma core region even when the width of the edge pedestal region, and the mode structure can expand deeply in strongly-shaped plasmas. This deeply expansion in strongly-shaped plasma is because the difference of the stabilizing effect of the ideal ballooning mode between the plasma edge region (including the edge pedestal region) and the region inside the pedestal in strongly shaped plasma is larger than that in weakly shaped plasma. This difference allows to destabilize the MHD mode whose structure extend from the edge pedestal region to the region inside the pedestal in strongly shaped plasma.
Isayama, Akihiko; JT-60 Team; Urso, L.*; Zohm, H.*; Maraschek, M.*; Hobirk, J.*
no journal, ,
no abstracts in English