Advanced tokamak research on long time scales in JT-60 Upgrade

Journal Article · Mon May 15 00:00:00 EDT 2006 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2187967· OSTI ID:20783137

Fujita, T ^[1]

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1. Fusion Research and Development Directorate, Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)

The duration of advanced tokamak plasma operation in JT-60 Upgrade (JT-60U) [A. Kitsunezaki et al., Fusion Sci. Technol. 42, 179 (2002)] has been extended on long time scales exceeding the current diffusion time ({tau}{sub R}) and close to the wall saturation time. A very high bootstrap current fraction (f{sub BS}) of 75% was maintained for 7.4 s (2.7{tau}{sub R}), while a normalized beta of 2.5 was maintained for 15.5 s ({approx}9.5{tau}{sub R}). The current profile reaches stationary conditions in {approx}{tau}{sub R} for the small f{sub BS} regime, while a longer time is required for the large f{sub BS} regime. A plasma with a weak shear q profile, similar to requirements for the ITER steady-state operational scenario, was successfully maintained. The particle inventory in the wall was observed to saturate in repeated long-pulse ({approx}30 s) H-mode discharges with edge localized modes. The analysis of neutral particles in the scrape-of-layer plasma indicates different time scales are involved for the wall saturation. Ferritic steel tiles have been installed in the vacuum vessel to reduce the toroidal field ripple towards extending the advanced tokamak regime further in the coming operational campaign.

• OSTI ID: 20783137
• Journal Information: Physics of Plasmas, Vol. 13, Issue 5; Other Information: DOI: 10.1063/1.2187967; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BOOTSTRAP CURRENT
BOUNDARY LAYERS
DIFFUSION
EDGE LOCALIZED MODES
ELECTRIC DISCHARGES
FERRITIC STEELS
H-MODE PLASMA CONFINEMENT
ITER TOKAMAK
JT-60 TOKAMAK
JT-60U TOKAMAK
NEUTRAL PARTICLES
PLASMA
PULSES
RADIATION TRANSPORT
SHEAR
STEADY-STATE CONDITIONS
WALL EFFECTS