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Shinohara, Koji; Isayama, Akihiko; Suzuki, Takahiro; Yoshida, Maiko
Purazuma, Kaku Yugo Gakkai-Shi, 91(7), p.494 - 496, 2015/07
no abstracts in English
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:23.85(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
Wakatsuki, Takuma; Suzuki, Takahiro; Hayashi, Nobuhiko; Shiraishi, Junya; Ide, Shunsuke; Takase, Yuichi*
Europhysics Conference Abstracts (Internet), 39E, p.P5.144_1 - P5.144_4, 2015/06
Wakatsuki, Takuma; Suzuki, Takahiro; Hayashi, Nobuhiko; Shiraishi, Junya; Ide, Shunsuke; Takase, Yuichi*
Plasma Physics and Controlled Fusion, 57(6), p.065005_1 - 065005_12, 2015/06
Times Cited Count:9 Percentile:40.64(Physics, Fluids & Plasmas)Kim, H.-S.*; Jeon, Y. M.*; Na, Y.-S.*; Ghim, Y.-C.*; Ahn, J.-W.*; Yoon, S. W.*; Bak, J. G.*; Bae, Y. S.*; Kim, J. S.*; Joung, M.*; et al.
Nuclear Fusion, 54(8), p.083012_1 - 083012_11, 2014/08
Times Cited Count:8 Percentile:37.25(Physics, Fluids & Plasmas)We evaluate the characteristics of global energy confinement in KSTAR () quantitatively by comparing it with multi-machine scalings, by deriving multiple regression equations for the L- and the H-mode plasmas, and evaluating confinement enhancement of the H-mode phase compared with the L-mode phase in each discharge. From the KSTAR database, of L-mode plasmas exhibits s to s and of H-mode plasmas s to s. The multiple regression equations derived by statistical analysis present the similar dependency on PL and slightly higher dependency on IP compared with the multi-machine scalings, however the dependency on elongation in both L- and H-mode plasmas draw the negative power dependency of and for H-mode and for L- mode database, respectively on the contrary to the positive dependency in all multi-machine empirical scalings. Although the reason is not clear yet, two possibilities are addressed. One is that the wall condition of KSTAR was not clean enough. The other is that striking points on the divertor plate were uncontrolled. For these reasons, as increases, the impurities from the wall can penetrate into plasmas easily. As a consequence, the confinement is degraded on the contrary to the expectation of multi-machine scalings.
Garcia, J.*; Hayashi, Nobuhiko; Giruzzi, G.*; Schneider, M.*; Joffrin, E.*; Ide, Shunsuke; Sakamoto, Yoshiteru; Suzuki, Takahiro; Urano, Hajime; JT-60 Team; et al.
Europhysics Conference Abstracts (Internet), 38F, p.P1.029_1 - P1.029_4, 2014/06
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:41.28(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.
Luce, T. C.*; Challis, C. D.*; Ide, Shunsuke; Joffrin, E.*; Kamada, Yutaka; Politzer, P. A.*; Schweinzer, J.*; Sips, A. C. C.*; Stober, J.*; Giruzzi, G.*; et al.
Nuclear Fusion, 54(1), p.013015_1 - 013015_15, 2013/12
Times Cited Count:35 Percentile:84.62(Physics, Fluids & Plasmas)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.
Kitamura, Akane; Kobayashi, Tomohiro*; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Suzuki, Akihiro*; Terai, Takayuki*
Nuclear Instruments and Methods in Physics Research B, 307, p.614 - 617, 2013/07
Times Cited Count:7 Percentile:48.84(Instruments & Instrumentation)Suzuki, Yoshiyuki*; Yamaguchi, Mitsutaka; Odaka, Hirokazu*; Shimada, Hirofumi*; Yoshida, Yukari*; Torikai, Kota*; Sato, Takahiro; Arakawa, Kazuo*; Kawachi, Naoki; Watanabe, Shigeki; et al.
Radiology, 267(3), p.941 - 947, 2013/06
Times Cited Count:23 Percentile:64.71(Radiology, Nuclear Medicine & Medical Imaging)Pace, D. C.*; Austin, M. E.*; Bass, E. M.*; Budny, R.*; Heidbrink, W. W.*; Hillesheim, J. C.*; Holcomb, C. T.*; Gorelenkova, M.*; Grierson, B. A.*; McCune, D. C.*; et al.
Physics of Plasmas, 20(5), p.056108_1 - 056108_18, 2013/05
Times Cited Count:33 Percentile:81.87(Physics, Fluids & Plasmas)Energetic ion transport due to microturbulence is investigated in MHD-quiescent plasmas by way of neutral beam injection in the DIII-D tokamak. A range of on-axis and off-axis beam injection scenarios are employed to vary relevant parameters such as the character of the background microturbulence and the value of Eb/Te, where Eb is the energetic ion energy and Te the electron temperature. In all cases it is found that any transport enhancement due to microturbulence is too small to observe experimentally. These transport effects are modeled using numerical and analytic expectations that calculate the energetic ion diffusivity due to microturbulence. It is determined that energetic ion transport due to coherent modes, including possible reductions in neutral beam current drive, is a considerably larger effect and should therefore be considered more important for ITER.
Giruzzi, G.*; Garcia, J.*; Hayashi, Nobuhiko; Schneider, M.*; Artaud, J. F.*; Baruzzo, M.*; Bolzonella, T.*; Farina, D.*; Figini, L.*; Fujita, Takaaki; et al.
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03
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
Suzuki, Takahiro; Nagasaki, Kazunobu*
Purazuma, Kaku Yugo Gakkai-Shi, 88(11), p.657 - 659, 2012/11
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