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T. Fujita, Y. Kamada, S. Ishida, Y. Neyatani,
T. Oikawa, S. Ide, S. Takeji, Y. Koide,
A. Isayama, T. Fukuda, T. Hatae, Y. Ishii,
T. Ozeki, H. Shirai and the JT-60 Team
Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, 311-0193 Japan
Abstract. The operation of JT-60U reversed shear discharges has been
extended to a high plasma current, low-q regime keeping a large radius of
the internal transport barrier (ITB) and the record value of equivalent
fusion multiplication factor in JT-60U,
QDTeq = 1.25, has been
achieved at 2.6 MA. Operational schemes to reach the low-q regime with good
reproducibility have been developed. The reduction of
Zeff was
obtained in the newly installed W-shaped pumped divertor. The
beta limit in the low-
qmin regime, which limited the
performance of
L-mode edge discharges, has been improved in H-mode edge
discharges with a broader pressure profile, which was obtained by power flow
control with ITB degradation. Sustainment of ITB and improved confinement
for 5.5 seconds has been demonstrated in an ELMy H reversed shear
discharge.
IAEA 2001
