Controllability of large bootstrap current fraction plasmas in JT-60U

Sakamoto, Yoshiteru; Takenaga, Hidenobu; Fujita, Takaaki; Ide, Shunsuke; Suzuki, Takahiro; Takechi, Manabu; Kamada, Yutaka; Oyama, Naoyuki; Isayama, Akihiko; Koide, Yoshihiko; JT-60 Team

Controllability of plasmas with a large bootstrap current fraction () has been investigated in JT-60U. Dynamic change in current profile, especially , which was induced by change in pressure profile at the internal transport barrier (ITB) through rotation control, was observed, indicating the strong linkage among the profiles. Response of pressure and current profiles to off-axis neutral beam injection is investigated and found that the alignment of peaks of total current profile and beam driven current profile affects to location, and the change in toroidal rotation induces the movement of ITB location. The current profile in strong reversed shear plasma without current hole is largely varied in the core region by electron cyclotron current drive, while the ITB structure is not affected.