[Table of Contents]

Plasma and Fusion Research

Volume 5, S1003 (2010)

Regular Articles

Advanced Tokamak Research in JT-60U and JT-60SA
Akihiko ISAYAMA for the JT-60 team
Japan Atomic Energy Agency, Naka, Ibaraki 311-0193, Japan
(Received 8 January 2009 / Accepted 8 July 2009 / Published 26 March 2010)

Abstract

Results of experiment in JT-60U and design study in JT-60SA (Super Advanced) are described focusing on the development of advanced tokamak. In JT-60U, a high-integrated performance plasma with the normalized beta βN = 2.6, confinement enhancement factor HH98(y,2) = 1.0-1.1 and bootstrap current fraction fBS = 0.4 has been sustained for 25 s (14 times current diffusion time (τR)). Neoclassical tearing mode (NTM) with the poloidal mode number m = 2 and the toroidal mode number n = 1 has been stabilized with modulated electron cyclotron current drive (ECCD) in synchronization with the mode frequency (∼5 kHz). A high-beta plasma exceeding the ideal MHD limit without conducting wall has been sustained for 5 s (∼3τR) by suppressing resistive wall mode (RWM). In addition, two new instabilities in the high-beta regime, Energetic particle driven Wall Mode (EWM) and RWM precursor, have been observed. In JT-60SA, exploration of full non-inductive steady-state operation with current drive by neutral beams and electron cyclotron waves is planned. In addition, NTM control with ECCD and RWM suppression with external coils are planned.

Keywords

advanced tokamak, ITER, hybrid scenario, NTM, RWM, JT-60U, JT-60SA

DOI: 10.1585/pfr.5.S1003

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This paper may be cited as follows:

Akihiko ISAYAMA for the JT-60 team, Plasma Fusion Res. 5, S1003 (2010).