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Yamamoto, Tsuyoshi; Yonekawa, Izuru*; Ota, Kazuya*; Hosoyama, Hiroki*; Hashimoto, Yasunori*; Wallander, A.*; Winter, A.*; Sugie, Tatsuo; Kusama, Yoshinori; Kawano, Yasunori; et al.
Fusion Engineering and Design, 87(12), p.2016 - 2019, 2012/12
Times Cited Count：2 Percentile：17.14(Nuclear Science & Technology)The ITER pulse scheduling system creates, approves and manage parameters that characterize plasma operation of ITER. JAEA analyzed requirements on the ITER plasma operations based on experience operating the JT-60U and designed essential functions. This system was designed to enable the change and reuse of parameters. The functions to support to check consistency between parameters and to assign parameter values are calculated by the system were proposed. These functions are useful to support operators.
Sakata, Shinya; Kiyono, Kimihiro; Sato, Minoru; Kominato, Toshiharu; Sueoka, Michiharu; Hosoyama, Hiroki; Kawamata, Yoichi
Fusion Engineering and Design, 84(7-11), p.1680 - 1683, 2009/06
Times Cited Count：1 Percentile：10.11(Nuclear Science & Technology)no abstracts in English
Suzuki, Takahiro; Ide, Shunsuke; Oikawa, Toshihiro; Fujita, Takaaki; Ishikawa, Masao; Seki, Masami; Matsunaga, Go; Hatae, Takaki; Naito, Osamu; Hamamatsu, Kiyotaka; et al.
Nuclear Fusion, 48(4), p.045002_1 - 045002_9, 2008/04
Times Cited Count：40 Percentile：80.54(Physics, Fluids & Plasmas)Aiming at optimization of current profile in high-b plasmas for higher confinement and stability, a real-time control system of the minimum of the safety factor (
) using the off-axis current drive has been developed. The off-axis current drive can raise safety factor in the center and help to avoid instability that limits performance of the plasma. The system controls injection power of lower-hybrid (LH) waves, and hence, its off-axis driven current in order to control 
. The real-time control of is demonstrated in a high-
plasma, where follows the temporally changing reference 
from 1.3 to 1.7. Applying the control to another high- discharge (
=1.7, 
=1.5) with 
=2/1 neo-classical tearing mode (NTM), was raised above 2 and the NTM was suppressed. The stored energy increased by 16% with the NTM suppressed, since the resonant rational surface was eliminated. For the future use for current profile control, current density profile for off-axis neutral beam current drive (NBCD) is for the first time measured, using motional Stark effect (MSE) diagnostic. Spatially localized NBCD profile was clearly observed at the normalized 
of about 0.6-0.8. The location was also confirmed by multi-chordal neutron emission profile measurement. The total amount of the measured beam driven current was consistent with the theoretical calculation using the ACCOME code. The CD location in the calculation was inward-shifted than the measurement.
Isayama, Akihiko; Suzuki, Takahiro; Hayashi, Nobuhiko; Ide, Shunsuke; Hamamatsu, Kiyotaka; Fujita, Takaaki; Hosoyama, Hiroki; Kamada, Yutaka; Nagasaki, Kazunobu*; Oyama, Naoyuki; et al.
AIP Conference Proceedings 933, p.229 - 236, 2007/10
no abstracts in English
Suzuki, Takahiro; Ide, Shunsuke; Oikawa, Toshihiro; Fujita, Takaaki; Ishikawa, Masao*; Seki, Masami; Matsunaga, Go; Takechi, Manabu; Naito, Osamu; Hamamatsu, Kiyotaka; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
For the first time, we have measured the current density profile for off-axis neutral beam current drive (NBCD), using motional Stark effect (MSE) diagnostic. A spatially localized NBCD profile was clearly observed at 
. The location was also confirmed by neutron emission profile measurement. The total amount of the driven current (0.15MA) was consistent with the decrease in the surface loop voltage. The off-axis current drive can raise safety factor (q) in the center and help to avoid instability that limits performance of the plasma. We have developed a real-time control system of the minimum q (qmin), using the off-axis current drive. Injection power of lower hybrid (LH) waves, and hence, its off-axis driven current controls qmin. In a high plasma (
, 
), the system was adopted to control qmin. With the control, qmin was raised and MHD fluctuations were suppressed. The stored energy increased by 16% with the MHD fluctuations suppressed.
Kurihara, Kenichi; Yonekawa, Izuru; Kawamata, Yoichi; Sueoka, Michiharu; Hosoyama, Hiroki*; Sakata, Shinya; Oshima, Takayuki; Sato, Minoru; Kiyono, Kimihiro; Ozeki, Takahisa
Fusion Engineering and Design, 81(15-17), p.1729 - 1734, 2006/07
Times Cited Count：13 Percentile：64.97(Nuclear Science & Technology)A large tokamak fusion device JT-60 is expected to explore more advanced tokamak discharge scenario towards the ITER and a future power reactor. We believe the following experimental issues are expected to be solved in JT-60. To clarify how to keep a steady-state plasma with high performance, and how to avoid plasma instabilities almost completely. By stimulus of this motivation, several essential development and modifications of plasma control and data acquisition systems have been performed in JT-60. In this report, we discuss the developments to improve the JT-60 plasma control and data acquisition systems. In addition, a future plasma control and data acquisition systems leading to a standard design for a power reactor is envisaged on the basis of the 20-year plasma operation experiences.
Yonekawa, Izuru; Sueoka, Michiharu; Hosoyama, Hiroki*; Kawamata, Yoichi; Suzuki, Takahiro; Kurihara, Kenichi
Fusion Engineering and Design, 81(15-17), p.1897 - 1903, 2006/07
Times Cited Count：2 Percentile：16.82(Nuclear Science & Technology)Recent years, plasma current profile (j-profile) control has been newly proposed to avoid instabilities in the high normalized-beta plasma. In particular, for the real-time profile feedback control, the control period should be roughly less than several tens of ms, including data communication among relating systems. In order to minimize data transfer time,the profile data being a function of time and position is required to decrease its data size for efficient data handling. A profile data,defined as 3-dimension time series data (q,R,Z,t), was reduced by introducing normalized minor radius rho in place of (R,Z). Data handling for profile control will be presented with their technical issues, together with computing hardware engineering.
Sueoka, Michiharu; Suzuki, Takahiro; Hosoyama, Hiroki
JAEA-Technology 2006-022, 44 Pages, 2006/03
JAEA-Technology-2006-022.pdf:3.61MB
no abstracts in English
Kurihara, Kenichi; Kawamata, Yoichi; Sueoka, Michiharu; Hosoyama, Hiroki*; Yonekawa, Izuru; Suzuki, Takahiro; Oikawa, Toshihiro; Ide, Shunsuke; JT-60 Team
Fusion Engineering and Design, 74(1-4), p.527 - 536, 2005/11
Times Cited Count：13 Percentile：62.13(Nuclear Science & Technology)Since tokamak magnetic fusion research has just made a step forward to an international collaborative project ITER, the existing tokamaks including JT-60 are expected to explore more advanced operation scenarios. To test those scenarios in the JT-60 experiment, the basic methods for understanding of plasma equilibrium have been developed. Some of them have been accomplished, and the other are being conducted as follows: (1) A complete plasma shape is precisely reproduced in real time. (2) Eddy current effects are considered for shape reproduction. (3) A plasma current profile in the poloidal cross-section is reproduced in real. (4) For long-pulse DT operation, a method is developed to correct the drifted signal of the integrator for a pick-up coil by employing distant sensor signals. In the symposium, those methods will be explained in detail with the experimental results at JT-60. On the basis of such discussion, we would like to envisage a future of plasma equilibrium control toward ITER and a fusion power plant.
Suzuki, Takahiro; Isayama, Akihiko; Ide, Shunsuke; Fujita, Takaaki; Oikawa, Toshihiro; Sakata, Shinya; Sueoka, Michiharu; Hosoyama, Hiroki*; Seki, Masami; JT-60 Team
AIP Conference Proceedings 787, p.279 - 286, 2005/09
A real-time control system of safety factor (q) profile was developed in JT-60. This system, for the first time, enables 1) real time evaluation of q profile using local magnetic pitch angle measurement by motional Stark effect (MSE) diagnostic and 2) control of current drive (CD) location (rhoCD) by adjusting the parallel refractive index 
of lower-hybrid (LH) waves through the change of phase difference (dphi) of LH waves between multi-junction launcher modules. The method for q profile evaluation was newly developed, without time-consuming reconstruction of equilibrium, so that the method requires less computational time. The system evaluates q profile within every 10ms, which is much faster than current relaxation time, typically order of 1s. Safety factor profile by the real-time calculation agreed well with that by equilibrium reconstruction with MSE. From temporal evolution of q (or current) profile, we evaluate CD location in real-time, too. The control system controls rhoCD through (or directly dphi) in such a way to minimize difference between the real-time evaluated q profile and its reference profile. The real-time control system was applied to positive shear plasmas (
), having plasma current of 0.6MA, toroidal field of 2.3T, and electron density of 
. In order to keep good coupling of LH waves to the plasma, gap between the launcher and the plasma surface was controlled to about 0.1m. The reference q profile was set to q(0)=1.3. The real-time q profile approached to the reference after application of real-time control; the controlled q profile was sustained for 3s, which was limited by injected LH power. RF experiments in JT-60U, such as stabilization of neo-classical tearing modes, plasma startup experiments, etc., are also presented.
Sueoka, Michiharu; Hosoyama, Hiroki*; Suzuki, Takahiro; Yonekawa, Izuru; Kurihara, Kenichi
Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03
no abstracts in English
discharges and real-time control of current profile in JT-60USuzuki, Takahiro; Isayama, Akihiko; Sakamoto, Yoshiteru; Ide, Shunsuke; Fujita, Takaaki; Takenaga, Hidenobu; Luce, T. C.*; Wade, M. R.*; Oikawa, Toshihiro; Naito, Osamu; et al.
Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11
no abstracts in English
Hosoyama, Hiroki*; Sueoka, Michiharu; Suzuki, Takahiro
KEK Proceedings 2003-16 (CD-ROM), 4 Pages, 2004/02
no abstracts in English
Hosoyama, Hiroki*; Sueoka, Michiharu; Kawamata, Yoichi
Heisei-14-Nendo Tokyo Daigaku Sogo Gijutsu Kenkyukai Gijutsu Hokokushu, p.359 - 361, 2003/03
no abstracts in English
Kurihara, Kenichi; Kawamata, Yoichi; Sueoka, Michiharu; Hosoyama, Hiroki; Suzuki, Takahiro; Fujita, Takaaki; Takenaga, Hidenobu; Ide, Shunsuke; Kamada, Yutaka
no journal, ,
no abstracts in English
