Steady-state operation scenarios with a central current hole for JT-60SC

Tamai, Hiroshi; Ishida, Shinichi; Kurita, Genichi; Sakamoto, Yoshiteru; Fujita, Takaaki; Shirai, Hiroshi; Tsuchiya, Katsuhiko; Matsukawa, Makoto; Sakasai, Akira; Sakurai, Shinji; et al.

Proceedings of 29th European Physical Society Conference on Plasma Physics and Controlled Fusion, 4 Pages, 2002/00

This paper presents the feasibility and issues of steady state operation with a central current hole for JT-60SC, the superconducting tokamak to be modified from JT-60, from the view of reactor applicability of the current hole. An impact of the current hole on fusion engineering would stand in no necessity of central current drive leading to a remarkable reduction of neutral beam injection energy. The 1.5D time-dependent transport code analysis is made with using thermal and particle transport coefficients deduced from observations in JT-60U as a function of the magnetic shear. A steady state operation with HHy2~1.6 and beta_N~4 is obtained at Ip=1.5 MA, Bt=2 T and q95=4.5 by off-axis beams of 11.2 MW. The bootstrap fraction of ~75% of the plasma current and the current hole region of ~30% of the minor radius are sustained up to 70 s. The results suggest that a bootstrap current evolution near the current hole region and a relation between the location of ITB and the central current hole region are important to achieve a steady state plasma compatible with the current hole.