Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Urano, Hajime; Fujita, Takaaki*; Ide, Shunsuke; Miyata, Yoshiaki; Matsunaga, Go; Matsukawa, Makoto
Fusion Engineering and Design, 100, p.345 - 356, 2015/11
Times Cited Count：19 Percentile：82.36(Nuclear Science & Technology)The operation scenarios for plasma breakdown and current ramp-up phases in JT-60SA tokamak have been developed. The induced current in the in-vessel conducting elements such as vacuum vessel and stabilizing plate increases to the comparable level of plasma current of 
600 kA during the breakdown phase and thus enhances the strength of error field. The optimized scenarios for half and full pre-magnetization cases satisfied the conditions required for the plasma initiation. At the initial plasma, the vertical magnetic field required to sustain the plasma position was controlled by the outer equilibrium field (EF) coil currents which compensate for a vertical field due to a large eddy current. The condition for the formation of divertor configurations given by the combination of the magnetic flux for plasma and the plasma current enables us to develop the operational scenarios with a smooth transition from a limiter to a divertor configuration.
Miyata, Yoshiaki; Suzuki, Takahiro; Takechi, Manabu; Urano, Hajime; Ide, Shunsuke
Review of Scientific Instruments, 86(7), p.073511_1 - 073511_13, 2015/07
Times Cited Count：5 Percentile：23.11(Instruments & Instrumentation)It is essential for a stable plasma equilibrium control to reconstruct an accurate plasma boundary in tokamak devices. Cauchy Condition Surface (CCS) method is a numerical approach to calculate the spatial distribution of the magnetic flux outside a hypothetical plasma surface and reconstruct the plasma boundary from the magnetic measurements located outside the plasma. It is found that the optimum number of unknown parameters and shape of the CCS for minimizing errors in the reconstructed plasma shape increase in proportion to the plasma size. It is shown that the accuracy of the plasma shape reconstruction greatly improves by using the optimum number of unknown parameters. The assessment of accuracy of plasma shape reconstruction by CCS method in JT-60SA is reported.
Hayashi, Nobuhiko; Honda, Mitsuru; Shiraishi, Junya; Miyata, Yoshiaki; Wakatsuki, Takuma; Hoshino, Kazuo; Toma, Mitsunori; Suzuki, Takahiro; Urano, Hajime; Shimizu, Katsuhiro; et al.
Europhysics Conference Abstracts (Internet), 39E, p.P5.145_1 - P5.145_4, 2015/06
Fukumoto, Masakatsu; Miyata, Yoshiaki; Tojo, Hiroshi
Purazuma, Kaku Yugo Gakkai-Shi, 91(5), P. 371, 2015/05
"18th Plasma Seminar for young researches" (by Department of Advanced Plasma Research, Sector of Fusion Research and Development, Japan Atomic Energy Agency) was held in Naka Fusion Institute, March 3rd through 6th of 2015. The objective of this seminar is that the young researchers in charge of the future fusion research expand their cross-sectoral network. This seminar was entitled "Crystallization of technology of plasma measurement and control" and we invited the lectures not just for fusion plasma but for technology of plasma measurement and control to study the technology of measurement and control of different fields from their fields. There were 8 invited lectures and 17 public lectures and young researchers had an animated discussion.
Kurihara, Kenichi; Itagaki, Masafumi*; Miyata, Yoshiaki; Nakamura, Kazuo*; Urano, Hajime
Purazuma, Kaku Yugo Gakkai-Shi, 91(1), p.10 - 47, 2015/01
no abstracts in English
Miyata, Yoshiaki; Suzuki, Takahiro; Ide, Shunsuke; Urano, Hajime
Plasma and Fusion Research (Internet), 9(Sp.2), p.3403045_1 - 3403045_5, 2014/05
The precise control of the plasma position is essential in safe and stable plasma operation. An MHD equilibrium control simulator has been developed in order to study the techniques of plasma equilibrium control for JT-60SA. In this study, the modules of plasma shape reconstruction, power supply, PF and FPPC coils are incorporated in order to simulate the real plasma equilibrium control. The plasma equilibrium control is simulated during Ip ramp-up within the power supply capability using MECS.
Miyata, Yoshiaki; Hahn, S. H.*; Suzuki, Takahiro; Ide, Shunsuke; Chung, J.*; Bak, J. G.*; Ko, W. H.*
Physics of Plasmas, 21(3), p.032502_1 - 032502_11, 2014/03
Times Cited Count：9 Percentile：40.15(Physics, Fluids & Plasmas)Cauchy condition surface (CCS) method is a numerical approach to reconstruct the plasma boundary precisely and calculate the quantities related to plasma shape using small number of magnetic diagnostics in real time. It has been applied to the KSTAR plasma in order to establish the plasma shape reconstruction with the high elongation of plasma shape and the large effect of eddy current flowing in the structure for the first time. Calculations have been performed to validate the plasma shape reconstruction in 2012 KSTAR experimental campaign. Comparison between the CCS calculation and non-magnetic measurements revealed that the CCS calculation can reconstruct the accurate plasma shape even with a small Ip. The application of CCS calculation to the KSTAR plasma and the validation results of the plasma shape reconstruction are reported.
Miyata, Yoshiaki; Suzuki, Takahiro; Ide, Shunsuke; Urano, Hajime; Fujita, Takaaki
Plasma and Fusion Research (Internet), 8(Sp.1), p.2405109_1 - 2405109_6, 2013/08
The precise control of the plasma position is a key issue in safe and stable plasma operation. A plasma equilibrium control simulator has been developed in order to study the techniques of plasma equilibrium control for JT-60SA. The simulator consists of an equilibrium solver and controller. The equilibrium solver identifies the plasma equilibrium under the given coil current and unknown eddy current by iteration. The function which calculates the self-consistent 
with magnetic flux consumption has been incorporated in order to simulate the control. The waveforms of JT-60SA plasma operation scenario during the ramp-up and the controllability of the plasma equilibrium control using the equilibrium control simulator were reported.
Ide, Shunsuke; Aiba, Nobuyuki; Bolzonella, T.*; Challis, C. D.*; Fujita, Takaaki; Giruzzi, G.*; Joffrin, E.*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Honda, Mitsuru; et al.
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03
Suzuki, Takahiro; Hayashi, Nobuhiko; Urano, Hajime; Miyata, Yoshiaki; Honda, Mitsuru; Ide, Shunsuke; JT-60SA Team
Europhysics Conference Abstracts (Internet), 37D, p.P2.136_1 - P2.136_4, 2013/00
no abstracts in English
Miyata, Yoshiaki; Suzuki, Takahiro; Fujita, Takaaki; Ide, Shunsuke; Urano, Hajime
Plasma and Fusion Research (Internet), 7, p.1405137_1 - 1405137_9, 2012/10
The plasma position and shape control is important issue in JT-60SA, ITER and future fusion reactor. In order to study the plasma position and shape control, we have developed a simulator which consists of an equilibrium solver and an "isoflux" controller. It is possible to simulate the position and shape control by using the "isoflux" technique and optimize the control logic of coil current in JT-60SA. It was demonstrated that the simulator can simulate the position and shape control in response to prescribed change in the configuration and internal parameters.
Ide, Shunsuke; Hayashi, Nobuhiko; Honda, Mitsuru; Urano, Hajime; Suzuki, Takahiro; Miyata, Yoshiaki; Aiba, Nobuyuki; Shiraishi, Junya; Kurita, Genichi; Fujita, Takaaki
Plasma and Fusion Research (Internet), 7(Sp.1), p.2403131_1 - 2403131_4, 2012/09
no abstracts in English
Kojima, Atsushi; Ishii, Kameo*; Miyata, Yoshiaki*; Kakiuchi, Hideto*; Kaido, Norihiro*; Yoshikawa, Masayuki*; Itakura, Akiyoshi*; Ichimura, Makoto*; Chujo, T.*
Fusion Science and Technology, 51(2T), p.274 - 276, 2007/02
Times Cited Count：2 Percentile：18.41(Nuclear Science & Technology)no abstracts in English
Hirata, Mafumi*; Miyake, Yasuhiro*; Chujo, T.*; Kohagura, Junko*; Numakura, Tomoharu*; Shimizu, Kiyoaki*; Ito, Marie*; Kiminami, Serina*; Morimoto, Naomichi*; Hirai, Katsuaki*; et al.
Review of Scientific Instruments, 77(10), p.10E719_1 - 10E719_3, 2006/10
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)no abstracts in English
Miyata, Yoshiaki; Suzuki, Takahiro; Ide, Shunsuke; Urano, Hajime; Takechi, Manabu
no journal, ,
It is essential for a stable plasma equilibrium control to reconstruct an accurate plasma boundary in tokamak devices. Cauchy Condition Surface (CCS) method is a numerical approach to calculate the spatial distribution of the magnetic flux outside a hypothetical plasma surface and reconstruct the plasma boundary from the magnetic measurements located outside the plasma. It is found that the optimum number of unknown parameters and shape of the CCS for minimizing errors in the reconstructed plasma shape increase in proportion to the plasma size. It is shown that the accuracy of the plasma shape reconstruction greatly improves by using the optimum number of unknown parameters. The assessment of accuracy of plasma shape reconstruction by CCS method in JT-60SA is reported.
Suzuki, Takahiro; Hayashi, Nobuhiko; Wakatsuki, Takuma; Miyata, Yoshiaki; Honda, Mitsuru; Ide, Shunsuke
no journal, ,
no abstracts in English
Fukumoto, Masakatsu; Yoon, S. W.*; Asakura, Nobuyuki; Miyata, Yoshiaki; Kubo, Hirotaka
no journal, ,
no abstracts in English
Miyata, Yoshiaki; Suzuki, Takahiro; Fujita, Takaaki; Ide, Shunsuke; Urano, Hajime
no journal, ,
no abstracts in English
Suzuki, Takahiro; Miyata, Yoshiaki; Ide, Shunsuke; Urano, Hajime; Fujita, Takaaki
no journal, ,
We have developed an equilibrium control simulator and investigated the JT-60SA operation scenario using the simulator. The simulator consists of an equilibrium construction component that solves temporal evolution of plasma coupled with conducting wall and a controller that controls the plasma current, position and shape via external coil current in the feedback manner. An operation scenario based on the feedback control has been developed, where the plasma current is raised by flux swing in center solenoids and plasma position and shapes are controlled in order to form divertor configuration and apply heating. Results on controllability of the position and shape during heating and flux swing and controllability of the vertical instability are presented as well.
Miyata, Yoshiaki; Hahn, S.-H.*; Suzuki, Takahiro; Ide, Shunsuke
no journal, ,
The accurate plasma shape reconstruction is essential for plasma equilibrium control and analysis. Various methods to reconstruct a plasma shape have been developed for constructions of tokamak devices. A plasma shape has been reconstructed by the method of Cauchy condition surface (CCS) from the magnetic measurements in JT-60U. The CCS calculation can reconstruct the outermost magnetic surface, and calculate the quantities related to plasma shape such as the Shafranov lambda, the safety factor, and so on. It was found that the plasma shape reconstructed by CCS calculation agreed well with the measurements in KSTAR. CCS is robust at Ip ramp up/down even with small Ip. In this presentation, the result of first application of CCS to the KSTAR plasma is discussed.
