Non-inductive current drive and profile control in JT-60U

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.49014· OSTI ID:279545

Ushigusa, K ^[1]

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1. Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Mukoyama 801-1, Naka-machi, Naka-gun, Ibaraki-ken (Japan)

Recent studies in JT-60U to establish physics base of a steady-state tokamak reactor are presented. High fusion performance with fusion triple product {ital n}{sub {ital D}}(0){tau}{sub {ital ET}}{sub {ital i}}(0)=1.2{times}10{sup 21} keVsm{sup {minus}3} (equivalent {ital Q}{sub {ital DT}}=0.6) has been achieved transiently in the high {beta}{sub {ital p}} {ital H}-mode regime. By optimizing the current and pressure profiles, a quasi steady-state high {beta}{sub {ital p}} {ital H}-mode with {ital n}{sub {ital D}}(0){tau}{sub {ital ET}}{sub {ital i}}(0)=(0.4{minus}0.5){times}10{sup 21} keVsm{sup {minus}3} (equivalent {ital Q}{sub {ital DT}}=0.25{minus}0.36) was maintained for up to 1.5 s. In order to maintain such high fusion performance discharges for a long time, non-inductive current drives and their capability of profile control were widely examined in the JT-60U tokamak. High-power ({approximately}7 MW) lower hybrid current drive (LHCD) experiments were performed by using a simplified multijunction launcher. A driven current of 3.6 MA has been achieved with a current drive efficiency of (0.3{minus}0.35){times}10{sup 20} m{sup {minus}2}A/W. Neutral beam current drive (NBCD) was also studied by using co/counter and on/off axis tangential beams ({approximately}4 MW). The maximum driven current and the current drive efficiency were 0.55 MA and 0.06{times}10{sup 20} m{sup {minus}2}A/W, respectively. Capability to control the current profile by LHCD and NBCD with a wide range of the plasma current was verified. Fully non-inductively driven discharges ({ital Ip}{le}1 MA) with good energy confinement ({tau}{sub {ital E}}/{tau}{sub {ital E}}{sup ITER89P}{le}2.5) and a high fraction of the bootstrap current ({ital I}{sub {ital BS}}/{ital I}{sub {ital p}}=0.6{minus}0.7) have been obtained with NBCD and/or LHCD. These results emphasized an importance of the profile control to obtain highly integrated tokamak performance. (Abstract Truncated)

• Sponsoring Organization: USDOE
• OSTI ID: 279545
• Report Number(s): CONF-9410130--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 345; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CURRENT-DRIVE HEATING
EXPERIMENT PLANNING
FUSION YIELD
LOWER HYBRID HEATING
PLASMA DIAGNOSTICS
STEADY-STATE CONDITIONS
TIMING PROPERTIES
TOKAMAK DEVICES
X RADIATION