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Fujita, Takaaki; JT-60 Team
Nuclear Fusion, 46(3), p.S3 - S12, 2006/03
Times Cited Count:8 Percentile:28.05(Physics, Fluids & Plasmas)no abstracts in English
Ogawa, Hiroaki; Ogawa, Toshihide; Tsuzuki, Kazuhiro; Kawashima, Hisato; Kasai, Satoshi*; Kashiwa, Yoshitoshi; Hasegawa, Koichi; Suzuki, Sadaaki; Shibata, Takatoshi; Miura, Yukitoshi; et al.
Fusion Science and Technology, 49(2), p.209 - 224, 2006/02
Times Cited Count:3 Percentile:24.11(Nuclear Science & Technology)no abstracts in English
Isayama, Akihiko; JT-60 Team
Physics of Plasmas, 12(5), p.056117_1 - 056117_10, 2005/05
Times Cited Count:28 Percentile:65.7(Physics, Fluids & Plasmas)no abstracts in English
Urano, Hajime; Kamada, Yutaka; Takizuka, Tomonori; Suttrop, W.*; Horton, L.*; Lang, P.*; Kubo, Hirotaka; Oyama, Naoyuki; Takenaga, Hidenobu; Asakura, Nobuyuki
Purazuma, Kaku Yugo Gakkai-Shi, 81(4), p.280 - 287, 2005/04
Role of the pedestal structure in ELMy H-mode plasmas for the core energy confinement and for the ELM energy losses have been investigated in JT-60U and ASDEX Upgrade. The confinement degradation seen at higher densities is attributed to the reduction of the pedestal temperature limited by the ELM activities and the stiffness of the temperature profiles. In high triangularity or impurity seeded H-modes, in which higher energy confinement is generally achieved, higher pedestal temperature is obtained by the improvement of the edge MHD stability or the density profile peaking, respectively. The upper bound of the ELM energy loss is characterised by the pedestal energy. The energy transport in between ELMs enhanced with increasing the pedestal collisionality reduces the ELM loss power fraction. It is also shown in ASDEX Upgrade that the continuous pellet injection is valid for the integrated performance of smaller ELM losses and favourable core confinement.
Kallenbach, A.*; Asakura, Nobuyuki; Kirk, A.*; Korotkov, A.*; Mahdavi, M. A.*; Mossessian, D.*; Porter, G. D.*
Journal of Nuclear Materials, 337-339, p.381 - 385, 2005/03
Times Cited Count:66 Percentile:96.56(Materials Science, Multidisciplinary)Edge profile data for H-mode discharges in 6 tokamaks have been analysed with the main focus on the edge density profile as well as electron temperature and density gradient lengths and steep gradient zone widths. A uniform procedure of data treatment and assignment of the separatrix position via power balance allowed to put the multi-machine data on an even base. The machine size appears to be the leading parameter for the width of the steep edge transport barrier gradient zone, as well as for the temperature decay length at the separatrix. Effects associated with neutral penetration physics are visible in the edge density profile.
Urano, Hajime
JAERI-Research 2004-027, 131 Pages, 2005/02
no abstracts in English
Asakura, Nobuyuki
Plasma Physics and Controlled Fusion, 46(12B), p.B335 - B347, 2004/12
Times Cited Count:18 Percentile:51.27(Physics, Fluids & Plasmas)Particle control of the main plasma density and exhaust of impurities ions have been demonstrated using the divertor pumping under saturated divertor condition. In JT-60U, ELMy H-mode operation was recently extended to 30s (with NB heating of 8-14 MW). Total number of injected particles reached (1-4)x1023 to maintain high densities. During the long pulse ELMy H-mode of JT-60U, gas puff rate was decreased from 15 to 3Pam3/s, while pumping rate was relatively constant of ~10 Pam3/s. Thus, the divertor plate was mostly saturated. It was found that 40-50% of the injected D was retained, which are comparable to Tore-Supra long pulse and JET high density ELMy H-mode pulse. Particle balance for long pulse and/or high density plasmas are discussed. Carbon flux generated by the chemical process was increased due to increase in the target temperature. Carbon generation and carbon ion emission were gradually increased in the outer leg of the divertor and the X-point. Shielding effect of the divertor was sustained and increment of the radiation power fraction was small in 30s.
Ishida, Shinichi; JT-60 Team; JFT-2M Group
Physics of Plasmas, 11(5), p.2532 - 2542, 2004/05
Times Cited Count:22 Percentile:57.92(Physics, Fluids & Plasmas)no abstracts in English
Saibene, G.*; Hatae, Takaki; Campbell, D. J.*; Cordey, J. G.*; la Luna, E. de.*; Giroud, C.*; Guenther, K.*; Kamada, Yutaka; Kempenaars, M. A. H.*; Loarte, A.*; et al.
Plasma Physics and Controlled Fusion, 46(5A), p.A195 - A205, 2004/05
Times Cited Count:10 Percentile:32.04(Physics, Fluids & Plasmas)Towards establishment of the control scheme and evaluation of the H-mode pedestal structure and behavior of the Edge Localized Mode (ELM) in ITER, we carried out an comparison experiment among the two large tokamaks (JT-60 and JET) for the first time. This paper report the initial results. In both devices, the same plasma shape was adopted and the three non-dimensional parameters (beta, normalized gyro radius and the normalized collisionality) were set identical. The pedestal width was almost similar in the two devices, however the pressure gradient was higher in JET by a factor of 1.5. The possible reason is a small aspect ration in JET.
Shimada, Michiya; Mukhovatov, V.*; Federici, G.*; Gribov, Y.*; Kukushkin, A.*; Murakami, Yoshiki*; Polevoi, A. R.*; Pustovitov, V. D.*; Sengoku, Seio; Sugihara, Masayoshi
Nuclear Fusion, 44(2), p.350 - 356, 2004/02
Recent performance analysis has improved confidence in achieving Q 10 in inductive operation in ITER. Performance analysis based on empirical scaling shows the feasibility of achieving Q 10 in inductive operation with a sufficient margin. Theory-based core modeling indicates the need of high pedestal temperature (2-4 keV) to achieve Q 10, which is in the range of projection with pedestal scaling. The heat load of type-I ELM could be made tolerable by high density operation and further tilting the target plate (if necessary). Pellet injection from High-Field Side would be useful in enhancing Q and reducing ELM heat load. Steady state operation scenarios have been developed with modest requirement on confinement improvement and beta (HH98(y,2) 1.3 and betaN 2.6). Stabilisation of RWM, required in such regimes, is feasible with the present saddle coils and power supplies with double-wall structure taken into account.
Shimada, Michiya; Mukhovatov, V.*; Federici, G.*; Gribov, Y.*; Kukushkin, A. S.*; Murakami, Yoshiki*; Polevoi, A. R.*; Pustovitov, V. D.*; Sengoku, Seio; Sugihara, Masayoshi
Nuclear Fusion, 44(2), p.350 - 356, 2004/02
Times Cited Count:39 Percentile:75.67(Physics, Fluids & Plasmas)Performance analysis based on empirical scaling shows the feasibility of achieving Q 10 in inductive operation. Analysis has also elucidated a possibility that ITER can potentially demonstrate Q 50, enabling studies of self-heated plasmas. Theory-based core modeling indicates the need of high pedestal temperature (3.2 - 5.3 keV) to achieve Q 10, which is in the range of projection with presently available pedestal scalings. Pellet injection from high-field side would be useful in enhancing Q and reducing ELM heat load in high plasma current operation. If the ELM heat load is not acceptable, it could be made tolerable by further tilting the target plate. Steady state operation scenarios at Q = 5 have been developed with modest requirement on confinement improvement and beta (HH98(y,2) 1.3 and betaN 2.6). Stabilisation of RWM, required in such regimes, is feasible with the present saddle coils and power supplies with double-wall structure taken into account.
Isayama, Akihiko; Kamada, Yutaka; Hayashi, Nobuhiko; Suzuki, Takahiro; Oikawa, Toshihiro; Fujita, Takaaki; Fukuda, Takeshi; Ide, Shunsuke; Takenaga, Hidenobu; Ushigusa, Kenkichi; et al.
Nuclear Fusion, 43(10), p.1272 - 1278, 2003/10
Times Cited Count:130 Percentile:95.67(Physics, Fluids & Plasmas)no abstracts in English
Isayama, Akihiko; Iwama, Naofumi*; Showa, Takeshi*; Hosoda, Yosuke*; Isei, Nobuaki; Ishida, Shinichi; Sato, Masayasu
Japanese Journal of Applied Physics, Part 1, 42(9A), p.5787 - 5796, 2003/09
Times Cited Count:3 Percentile:15.63(Physics, Applied)no abstracts in English
Kawashima, Hisato; Sengoku, Seio; Tsuzuki, Kazuhiro; Ogawa, Hiroaki; Kimura, Haruyuki
Journal of Nuclear Materials, 313-316, p.1338 - 1342, 2003/03
Times Cited Count:3 Percentile:25.79(Materials Science, Multidisciplinary)no abstracts in English
Isayama, Akihiko; Nagasaki, Kazunobu*; Ide, Shunsuke; Fukuda, Takeshi*; Suzuki, Takahiro; Seki, Masami; Moriyama, Shinichi; Ikeda, Yoshitaka; JT-60 Team
AIP Conference Proceedings 694, p.321 - 324, 2003/00
no abstracts in English
Kusama, Yoshinori; JFT-2M Group
Proceedings of 30th EPS Conference on Controlled Fusion and Plasma Physics (CD-ROM), 4 Pages, 2003/00
no abstracts in English
Fukuda, Takeshi; Oikawa, Toshihiro; Takeji, Satoru; Isayama, Akihiko; Kawano, Yasunori; Neyatani, Yuzuru; Nagashima, Akira; Nishitani, Takeo; Konoshima, Shigeru; Tamai, Hiroshi; et al.
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.357 - 367, 2002/09
Times Cited Count:7 Percentile:44.35(Nuclear Science & Technology)no abstracts in English
Kamada, Yutaka; Fujita, Takaaki; Ishida, Shinichi; Kikuchi, Mitsuru; Ide, Shunsuke; Takizuka, Tomonori; Shirai, Hiroshi; Koide, Yoshihiko; Fukuda, Takeshi; Hosogane, Nobuyuki; et al.
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.185 - 254, 2002/09
Times Cited Count:34 Percentile:48.48(Nuclear Science & Technology)With the main aim of providing physics basis for ITER and the steady-state tokamak reactors, JT-60/JT-60U has been developing and optimizing the operational concepts, and extending the discharge regimes toward sustainment of high integrated performance in the reactor relevant parameter regime. In addition to achievement of the equivalent break-even condition (QDTeq up to 1.25) and a high fusion triple product = 1.5E21 m-3skeV, JT-60U has demonstrated the integrated performance of high confinement, high beta-N, full non-inductive current drive with a large fraction of bootstrap current in the reversed magnetic shear and in the high-beta-p ELMy H mode plasmas characterized by both internal and edge transport barriers. The key factors in optimizing these plasmas are profile and shape controls. As represented by discovery of various Internal Transport Barriers, JT-60/JT-60U has been emphasizing freedom and restriction of profiles in various confinement modes. JT-60U has demonstrated applicability of these high confinement modes to ITER and also clarified remaining issues.
Fukuda, Takeshi; Takizuka, Tomonori; Fujita, Takaaki; Sakamoto, Yoshiteru; Kamada, Yutaka; Ide, Shunsuke; Koide, Yoshihiko; Takenaga, Hidenobu; Miura, Yukitoshi
Plasma Physics and Controlled Fusion, 44(5A), p.A341 - A349, 2002/05
Times Cited Count:7 Percentile:24.31(Physics, Fluids & Plasmas)no abstracts in English
Kamada, Yutaka; Takenaga, Hidenobu; Isayama, Akihiko; Hatae, Takaki; Urano, Hajime*; Kubo, Hirotaka; Takizuka, Tomonori; Miura, Yukitoshi
Plasma Physics and Controlled Fusion, 44(5A), p.A279 - A286, 2002/05
Times Cited Count:77 Percentile:89.73(Physics, Fluids & Plasmas)no abstracts in English