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Kobayashi, Takayuki; Isayama, Akihiko; Yokokura, Kenji; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Hoshino, Katsumichi; et al.
no journal, ,
Development of high-power, long-pulse electron cyclotron range of frequency heating system for JT-60SA is in progress. A dual frequency gyrotron was developed in order to extend operation regime of the system. Short pulse oscillations at 110 GHz and 138 GHz were obtained up to 1 MW and 0.5 MW, respectively. Observed power, efficiency, frequency and beam location at the output window were consistent with the design. Long pulse operations of a 110 GHz gyrotron with a large diameter waveguide transmission line at 1 MW were also carried out. Pulse duration of 70 s, which was twice longer than the previous record, was obtained. High power operation of 1.4 MW for 9 s was also obtained by applying a high efficiency operation technique. Progress in research and developments of transmission line components and antenna for enabling dual frequency operation is also presented.
Hanada, Masaya; Kojima, Atsushi; Akino, Noboru; Komata, Masao; Mogaki, Kazuhiko; Oh, B. H.*; Jeong, S. H.*; Chang, D. H.*; Lee, K. W.*; Bae, Y. S.*
no journal, ,
no abstracts in English
Moriyama, Shinichi; Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; et al.
no journal, ,
Long pulse operation of the dual frequency gyrotron was started for JT-60SA ECH system. Pulse lengths of 10 s with output power of 1MW were obtained at both 110 GHz and 138 GHz, so far. Typical oscillation efficiency is approximately 30%. Diffraction loss was acceptable for long pulse 1 MW output. The first high power test of the "power / beam profile monitor" featuring a fast movable Si
3N
disk in the waveguide slit was successfully demonstrated.
Ikeda, Ryosuke; Kajiwara, Ken; Oda, Yasuhisa; Takahashi, Koji; Kobayashi, Takayuki; Moriyama, Shinichi; Sakamoto, Keishi
no journal, ,
TE
mode gyrotron has advantages for multi-frequency oscillation. Triple frequency of 170 GHz, 137 GHz and 104 GHz pass through a diamond disk window without a reflection lose and are radiated toward the same direction without moving a final mirror in the gyroton. In short pulse experiments (
5s), the output power, the oscillation efficiency and the electric efficiency for 170 GHz, 137 GHz and 104 GHz oscillation achieved 1.2 MW/27%/43%, 810 kW/25%/40% and 720 kW/25%/38%. In long pulse operation, pulse length reached 100s with 870 kW output power for 170 GHz oscillation. HE11 mode purity measured at the MOU exit was 94.5%, 93% and 92% for 170 GHz, 137 GHz and 104 GHz oscillation. By building precisely a transmission line, the purity of 91%, 88% and 95%, respectively is obtained at the exit of the long transmission line (35 m).
Hiratsuka, Junichi; Hanada, Masaya; Kojima, Atsushi; Umeda, Naotaka; Kashiwagi, Mieko; Yoshida, Masafumi; Nishikiori, Ryo; Ichikawa, Masahiro; Watanabe, Kazuhiro; Tobari, Hiroyuki
no journal, ,
New technologies for the high power and long pulse negative ion beam sources have been developed with R&D activities on the JT-60SA ion source and the ITER prototype accelerator in Japan Atomic Energy Agency. R&D progress of the temperature control of the plasma grid resulted in the long pulse negative ion production of 100 s with high current of 15 A, which satisfies the required pulse duration and 70 % of the beam current for JT-60SA. R&D progress of accelerator design for the voltage holding capability and the grid power loading improved the pulse duration with high power density of 185 MW/m
(974 keV, 190 A/m) from 0.4 s to 60 s, which has reached the ITER requirement level for power density of 200 MW/m. The total power loading on the acceleration grids was less than 13 % of the input power for the 60 s accelerated beams, which is less than the ITER accelerator design of 20 %.
Ikeda, Yoshitaka; JT-60SA Team
no journal, ,
The main objectives of the JT-60SA are to demonstrate steady-state high-beta plasma, and to support ITER through the optimization of ITER operation scenario. To attain these objectives, the JT-60SA is designed to be the superconducting tokamak with a wide range of diverted plasma configurations. Powerful heating systems of total power of 41 MW for 100s is required to allow the JT-60SA to be operated in break-even equivalent conditions for a long pulse duration. Design and fabrication of JT-60SA components, shared by the EU and Japan, started in 2007. Assembly in the torus hall started in 2013, and welding work of the vacuum vessel sectors is currently ongoing on the cryostat base. Other components such as TF coils, PF coils, power supplies, cryogenic system, cryostat vessel, thermal shields and so on were or are being delivered to the Naka site for installation, assembly and commissioning towards the first plasma in 2019.
Moriyama, Shinichi; Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Wada, Kenji; Hinata, Jun; Sato, Fumiaki; Yokokura, Kenji; Hoshino, Katsumichi; et al.
no journal, ,
Assembly of the JT-60SA and preparation of its ECH system are progressing and the first plasma is planned in 2019. The high voltage power supply for two gyrotrons will be procured by EU. The procurement arrangement was signed in July 2015. Its fabrication in EU will be done in 2016 and the installation to the Naka-site will be in 2017. Oscillations at 1 MW for 100 s as the development target of the JT-60SA gyrotron were achieved at both 110 GHz and 138 GHz in June 2014. The gyrotron is the first "1 MW multi-frequency gyrotron" reached the pulse duration of 100s at two frequencies. In addition, 82 GHz oscillation was achieved at 1.0 MW for 1 sec by this gyrotron in June 2015. This additional frequency would be applicable to plasma start-up assistance and wall conditioning at the fundamental EC resonance in JT-60SA. Development is steadily progressing on the waveguide components and the launcher.
Ikeda, Ryosuke; Oda, Yasuhisa; Kobayashi, Takayuki; Kajiwara, Ken; Takahashi, Koji; Moriyama, Shinichi; Sakamoto, Keishi
no journal, ,