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,
, has been
achieved at 2.6 MA. Operational schemes to reach the low-q regime with good
reproducibility have been developed. The reduction of was
obtained in the newly installed W-shaped pumped divertor. The
beta limit in the low- 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 1999