Development of cold isostatic pressing graphite module for a heat-resistant lower hybrid current drive antenna

Maebara, Sunao; Goniche, M.*; Kazarian, F.*; Seki, Masami; Ikeda, Yoshitaka; Imai, Tsuyoshi*; Beaumont, B.*

Review of Scientific Instruments, 76(5), p.053501_1 - 053501_7, 2005/05

https://doi.org/10.1063/1.1891465

Development of a plasma facing module using Cold Isostatic Pressing Graphite (CIPG) had been done for a heat-resistant LHCD antenna. A thin stainless film (10m), molybdenum film (10m) and copper film (50m) are laid to overlap each other on the CIPG materials, the CIPG surfaces were successfully coated with copper layer by diffusion bonding method. This module has four waveguides and a water cooling channel, the length is 206 mm. High power long pulse operation was successfully achieved up to 250 kW (125 MW/m)/700s. The module has been successfully tested at a RF power density which is equivalent, in terms of RF electric field (5kV/cm), to the one proposed for the LHCD antenna of ITER-FEAT. The outgassing rate of the copper-coated CIPG is estimated to be 3.2-5.110 Pa.m/s.m at 100C, it is assessed that a pumping system is not required to evacuate the pressure in the LHCD antenna.

Profile control and plasma start-up by RF waves towards advanced tokamak operation in JT-60U

Takase, Yuichi*; JT-60 Team

AIP Conference Proceedings 694, p.235 - 242, 2003/05

https://doi.org/10.1063/1.1638033

A central electron temperature of 23 keV was obtained by EC wave injection. A highly localized current density profile was obtained by central ECCD, indicating an upper limit on the diffusion coefficient for resonant electrons of . The experimentally obtained current drive figure of merit was lower than theoretical prediction, possibly because of the negative loop voltage induced by overdrive. A comparison of HFS and LFS off-axis ECCD confirmed the theoretically expected trapped particle effect on the current drive efficiency. Offaxis LHCD was used to broaden the qmin radius and the ITB foot radius. N-NBCD was used to shrink the current hole radius. An integrated scenario consisting of (1) a novel plasma start-up method using RF plasma production and induction by vertical field and shaping coils, (2) a noninductive ramp-up stage, and (3) a transition to a high-density, bootstrap-dominated, highconfinement plasma, without the use of the OH solenoid, has been demonstrated. The plasma created by this technique had both internal and edge transport barriers, with (), , and at MA and .

Noninductive current drive and steady-state operation in JT-60U

Ushigusa, Kenkichi; Ide, Shunsuke; Oikawa, Toshihiro; Suzuki, Takahiro; Kamada, Yutaka; Fujita, Takaaki; Ikeda, Yoshitaka; Naito, Osamu; Matsuoka, Mamoru*; Kondoh, Takashi; et al.

Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.255 - 277, 2002/09

https://doi.org/10.13182/FST02-A228

Studies on non-inductive current drive and development of an integrated steady-state high performance operation in JT-60 are reviewed. Experiments on lower hybrid current drive in JT-60 haven shown a large non-inductive current up to 3.5MA, high current drive efficiency of 3.6x1019m-2A/W. Basic studies on LH waves in JT-60 have contributed to understand current drive physics. Significant progress in neutral beam current drive has been made in JT-60 by testing the performance of negative ion based NBI (N-NBI). The CD efficiency of ~1.5x1019m-2A /W, and N-NB driven current of ~1MA have been demonstrated in N-NBCD. Strongly localized driven current by electron cyclotron current drive was identified with a fundamental O-mode scheme. Efficiency of 0.5x1019m-2A/W and EC driven current of 0.2MA were achieved and suppression of neo-classical tearing mode was demonstrated. Based on these developments, two integrated steady-state operation scenarios were developed in JT-60, which are reversed magnetic shear (R/S) plasmas and high bp ELMy H-mode. In these operation regimes, discharges have been sustained near the steady-state current profile under full non-inductive current drive. High performance plasmas with a high nDotETio and at high normalized density were also produced under fully non-inductive condition in high bp ELMy H-mode and R/S mode.

Formation of internal transport barriers and its impact on the JT-60U plasmas

Ide, Shunsuke; JT-60 Team

Journal of Plasma and Fusion Research SERIES, Vol.4, p.99 - 105, 2001/00

no abstracts in English

Lower hybrid current drive in tokamak plasmas

Ushigusa, Kenkichi

JAERI 1339, 77 Pages, 1999/03

JAERI-1339.pdf:3.4MB

no abstracts in English

Development of a power divider in the plane using posts in a rectangular waveguide for the next generation lower hybrid current drive antenna

Seki, Masami; Maebara, Sunao; ; Ikeda, Yoshitaka; Imai, Tsuyoshi; Hirokawa, Jiro*; Arai, Hiroyuki*

Fusion Engineering and Design, 36(2-3), p.281 - 287, 1997/05

https://doi.org/10.1016/S0920-3796(96)00699-0

no abstracts in English

Development of a power divider in the H plane using posts in a rectangular waveguide for the next generation lower hybrid current drive antenna

Seki, Masami; Maebara, Sunao; *; Ikeda, Yoshitaka; Imai, Tsuyoshi; *; *

Fusion Engineering and Design, 36(2-3), p.281 - 287, 1997/00

https://doi.org/10.1016/S0920-3796(96)00699-0

no abstracts in English

Application of LHCD for sustainment and control of a reversed magnetic shear plasmas in JT-60U

Ide, Shunsuke; Naito, Osamu; Fujita, Takaaki; Oikawa, Toshihiro; Seki, Masami; JT-60 Team

IAEA-CN-64/E-3, 10 Pages, 1996/10

no abstracts in English

Performance test of lower hybrid waveguide under long/high-RF power transmission

Seki, Masami; Obara, Kenjiro; Maebara, Sunao; Ikeda, Yoshitaka; Imai, Tsuyoshi; Nagashima, Takashi; Goniche, M.*; J.Brossaud*; C.Barral*; G.Berger-By*; et al.

JAERI-Research 96-025, 55 Pages, 1996/06

JAERI-Research-96-025.pdf:2.06MB

no abstracts in English

Response of lower hybrid wave driven current profile on wave launching position

Ide, Shunsuke; Naito, Osamu; Kondoh, Takashi; Ikeda, Yoshitaka; Ushigusa, Kenkichi

Nuclear Fusion, 36(8), p.1057 - 1061, 1996/00

https://doi.org/10.1088/0029-5515/36/8/I10

no abstracts in English