Demonstration of real-time feedback control of ion temperature gradient and toroidal rotation using developed fast CXRS system in JT-60U

Yoshida, Maiko; Sakamoto, Yoshiteru; Sueoka, Michiharu; Kawamata, Yoichi; Oyama, Naoyuki; Suzuki, Takahiro; Kamada, Yutaka

A fast charge exchange recombination spectroscopy (CXRS) system has been developed for the real-time measurement and feedback control of ion temperature (Ti) profile and toroidal rotation velocity (Vt) in JT-60U. In order to control Ti and Vt in real-time, the charge exchange recombination spectroscopy with high time resolution, the real-time processor system, and the real-time control system have been developed. Utilizing this system, real-time control of the Ti gradient between r/a 0.25-0.5 has been demonstrated with neutral beams at high beta plasmas. The strength of the internal transport barrier is controlled. Moreover, the real-time control of Vt has been demonstrated from counter to co direction. Then the behavior of edge localized mode (ELM) changed by controlling the Vt.