Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
RuO
proved by spin resonanceIida, Kazuki*; Kofu, Maiko; Suzuki, Katsuhiro*; Murai, Naoki; Kawamura, Seiko; Kajimoto, Ryoichi; Inamura, Yasuhiro; Ishikado, Motoyuki*; Hasegawa, Shunsuke*; Masuda, Takatsugu*; et al.
Journal of the Physical Society of Japan, 89(5), p.053702_1 - 053702_5, 2020/05
Times Cited Count：19 Percentile：80.6(Physics, Multidisciplinary)Kokusen, Shigeharu; Yoshida, Maiko; Tojo, Hiroshi
JAEA-Technology 2015-041, 26 Pages, 2016/02
JAEA-Technology-2015-041.pdf:8.03MB
Shutters will be installed in front of vacuum windows of some diagnostics in JT-60SA to avoid deposition of impurity onto the vacuum window during wall cleaning and plasma conditioning. Two types of shutter systems had been designed. One has a light shutter (0.5 kg) with rotary motion in vacuum. Another has a heavy shutter (3 kg) with vertical motion in vacuum. For the both types, malfunction due to increase of friction coefficients of the sliding parts in vacuum is concerned. In the present paper, Durability, abrasion and friction coefficient of the sliding parts has been investigated and the shutter designs have been validated. The light shutter with rotary motion successfully rotated required times (4000 times), and the design was validated. On the other hand, for the heavy shutter with vertical motion, the test could not be carried out due to the large friction of the sliding parts. This result suggests that we should change the material of the sliding parts to reduce the friction or change the design from the sliding structure to other ones such as a structure using pulleys and bearings. In the test of the heavy shutter with vertical motion, the friction coefficient increased from 1.3 to 4.5 in the vacuum chamber and from 0.4 to 2.5 in the air.
Yoshida, Maiko; Honda, Mitsuru; Narita, Emi*; Hayashi, Nobuhiko; Urano, Hajime; Nakata, Motoki; Miyato, Naoaki; Takenaga, Hidenobu; Ide, Shunsuke; Kamada, Yutaka
Nuclear Fusion, 55(7), p.073014_1 - 073014_9, 2015/07
Times Cited Count：14 Percentile：57.47(Physics, Fluids & Plasmas)Conditions without the increases in the thermal and particle transport with ECH have been experimentally investigated in positive magnetic shear (PS), weak magnetic shear (WS) and reversed magnetic shear (RS) plasmas with internal transport barriers (ITBs) on JT-60U. The ion heat diffusivity around an internal transport barrier in the ion temperature (
-ITB) remains constant with ECH when a large negative toroidal rotation shear is formed before the ECH. The condition does not depend on the electron to ion temperature ratio (
/) and ECH power. The electron heat diffusivity around a -ITB stays constant with ECH when the magnetic shear is negative around the Te-ITB region. Effective particle transport remains constant or reduces during ECH under the condition of negative magnetic shear.
Honda, Mitsuru; Satake, Shinsuke*; Suzuki, Yasuhiro*; Yoshida, Maiko; Hayashi, Nobuhiko; Kamiya, Kensaku; Matsuyama, Akinobu; Shinohara, Koji; Matsunaga, Go; Nakata, Motoki; et al.
Nuclear Fusion, 55(7), p.073033_1 - 073033_11, 2015/07
Times Cited Count：7 Percentile：32.76(Physics, Fluids & Plasmas)Shinohara, Koji; Isayama, Akihiko; Suzuki, Takahiro; Yoshida, Maiko
Purazuma, Kaku Yugo Gakkai-Shi, 91(7), p.494 - 496, 2015/07
no abstracts in English
Urano, Hajime; Nakata, Motoki; Aiba, Nobuyuki; Kubo, Hirotaka; Honda, Mitsuru; Hayashi, Nobuhiko; Yoshida, Maiko; Kamada, Yutaka; JT-60 Team
Nuclear Fusion, 55(3), p.033010_1 - 033010_9, 2015/03
Times Cited Count：41 Percentile：89.24(Physics, Fluids & Plasmas)Physics picture of improving energy confinement with argon seeding at high density has been investigated in JT-60U. Better confinement is sustained at high density by argon seeding accompanied by higher core and pedestal temperatures. Peaked density profiles are kept with argon seeding. Density peaking and dilution effects lower the pedestal density at a given averaged density. The pedestal density in the argon seeded plasmas which is relatively lower than that in a single deuterium puff enables the pedestal temperature to be higher. The density peaking is a key factor of sustaining better confinement in argon seeded H-mode plasmas.
Kamiya, Kensaku; Honda, Mitsuru; Urano, Hajime; Yoshida, Maiko; Kamada, Yutaka; Ito, Kimitaka*; JT-60 Team
Physics of Plasmas, 21(12), p.122517_1 - 122517_8, 2014/12
Times Cited Count：13 Percentile：53.93(Physics, Fluids & Plasmas)Modulation Charge eXchange Recombination Spectroscopy (MCXRS) measurements with high spatial and temporal resolution have made the evaluation of the toroidal plasma flow of fully stripped carbon impurity ions in the JT-60U tokamak peripheral region (including in particular separatrix) possible with a better signal-to-noise ratio. Boundary condition of Vt imposed at the separatrix in ELMy H-mode plasmas has been identified, comparing between co- and counter-NBI discharges. The Vt value at the separatrix is not held fixed at the zero, varying with momentum input direction, but being not strongly affected by the ELM event. A non-zero Vt value at the separatrix might be connected to fast ion losses due to toroidal field ripple that results in formation of a negative radial electric field (Er) layer having almost zero (or very weak positive) Er-shear value at the separatrix. Improved understanding of physics process in pedestal structure formation for the Vt and Er is also discussed.
Honda, Mitsuru; Satake, Shinsuke*; Suzuki, Yasuhiro*; Matsunaga, Go; Shinohara, Koji; Yoshida, Maiko; Matsuyama, Akinobu; Ide, Shunsuke; Urano, Hajime
Nuclear Fusion, 54(11), p.114005_1 - 114005_14, 2014/11
Times Cited Count：15 Percentile：59(Physics, Fluids & Plasmas)Honda, Mitsuru; Satake, Shinsuke*; Suzuki, Yasuhiro*; Yoshida, Maiko; Hayashi, Nobuhiko; Kamiya, Kensaku; Matsuyama, Akinobu; Shinohara, Koji; Matsunaga, Go; Nakata, Motoki; et al.
Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10
Urano, Hajime; Nakata, Motoki; Aiba, Nobuyuki; Kubo, Hirotaka; Honda, Mitsuru; Yoshida, Maiko; Hayashi, Nobuhiko; Kamada, Yutaka; JT-60 Team
Europhysics Conference Abstracts (Internet), 38F, p.P4.018_1 - P4.018_4, 2014/06
This paper reports the analysis result of heat transport and pedestal structure in H-mode plasmas with and without argon seeding on JT-60U.
Yoshida, Maiko; Shinohara, Koji; Hayashi, Nobuhiko; Isayama, Akihiko; Kamiya, Kensaku
Purazuma, Kaku Yugo Gakkai-Shi, 89(12), p.887 - 889, 2013/12
ITPA (International Tokamak Physics Activity) meetings were held in Autumn 2013.
Honda, Mitsuru; Satake, Shinsuke*; Suzuki, Yasuhiro*; Matsunaga, Go; Ide, Shunsuke; Yoshida, Maiko; Hayashi, Nobuhiko
Europhysics Conference Abstracts (Internet), 37D, p.P1.182_1 - P1.182_4, 2013/07
Yoshida, Maiko; Ide, Shunsuke; Takenaga, Hidenobu; Honda, Mitsuru; Urano, Hajime; Kobayashi, Takayuki; Nakata, Motoki; Miyato, Naoaki; Kamada, Yutaka
Nuclear Fusion, 53(8), p.083022_1 - 083022_10, 2013/07
Times Cited Count：7 Percentile：30.13(Physics, Fluids & Plasmas)Time and special responses of electron channels and ion channels with central electron cyclotron heating (ECH) have been investigated in JT-60U positive shear H-mode and internal transport barrier (ITB) plasmas. The ion temperature reduces with ECH after the increase in the electron temperature where an increase in the ion heat transport with ECH accompanies an increase in the electron thermal transport. The core electron density decreases with ECH when the density profile is peaked before ECH injection. The counter intrinsic rotation with ECH is identified using H-mode plasmas with small torque input (BAL-NBI). The counter intrinsic rotation is generated after the increase in the electron temperature and correlates with the change in the electron temperature with ECH around the EC deposition. Time scale of the change in the toroidal rotation velocity is about 90-200 ms around the ECH deposition and the time scale is longer compared to those in 
and 
.
Honda, Mitsuru; Ide, Shunsuke; Takizuka, Tomonori*; Hayashi, Nobuhiko; Yoshida, Maiko; Yagi, Masatoshi; Fujita, Takaaki
Nuclear Fusion, 53(7), p.073050_1 - 073050_11, 2013/07
Times Cited Count：22 Percentile：69.44(Physics, Fluids & Plasmas)Honda, Mitsuru; Hayashi, Nobuhiko; Takizuka, Tomonori*; Yoshida, Maiko; Fujita, Takaaki
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03
Yoshida, Maiko; Kaye, S.*; Rice, J.*; Solomon, W.*; Tala, T.*; Bell, R. E.*; Burrell, K. H.*; Ferreira, J.*; Kamada, Yutaka; McDonald, D. C.*; et al.
Nuclear Fusion, 52(12), p.123005_1 - 123005_11, 2012/11
Times Cited Count：17 Percentile：58.65(Physics, Fluids & Plasmas)The purpose of this study is to find a common feature on momentum transport coefficients including diffusive and non-diffusive terms in all machines. The momentum database enables us to assess a parametric dependency of momentum transport in a wider range of dimensionless parameters related to transport. Such observation will contribute to make a scaling/modeling on momentum transport for future devices like ITER and DEMO. On the other hand, the investigation of a difference in observation by comparing the experimental conditions will give a useful information to realize what plasma parameter is the key for the momentum transport coefficients.
Yoshida, Maiko
Purazuma, Kaku Yugo Gakkai-Shi, 88(11), p.651 - 653, 2012/11
This issues is a introductory text on the JT-60SA Research Plan for young scientists in Japan. Section 1 describes the purpose and activity of the JT-60SA Research Plan. Sections 2-10 show the summary of the research items in JT-60SA which were written in the technical responsible officer in each research area. Sections 3-10 discuss the issues in ITER and DEMO firstly, and then describe the research items and plans in JT-60SA to address these issues. The technical responsible officers also share the needs and messages for the first plasma in JT-60SA.
Yoshida, Maiko; Tanaka, Kenji*
Purazuma, Kaku Yugo Gakkai-Shi, 88(11), p.663 - 665, 2012/11
Transport and confinement studies in JT-60SA will take advantage of its ability to operate highly shaped, long lasting discharges while heating both ions and electrons through a flexible NBI (PNB, NNB) and ECRF systems. The JT-60SA transport and confinement studies will be focused on answering those critical questions and tackle those open issues attaining to experimental regimes of ITER and DEMO that can be directly simulated in a Super Advanced Tokamak.
Kamiya, Kensaku; Honda, Mitsuru; Miyato, Naoaki; Urano, Hajime; Yoshida, Maiko; Sakamoto, Yoshiteru; Matsunaga, Go; Oyama, Naoyuki; Koide, Yoshihiko; Kamada, Yutaka; et al.
Nuclear Fusion, 52(11), p.114010_1 - 114010_12, 2012/10
Times Cited Count：10 Percentile：40.68(Physics, Fluids & Plasmas)Depending on the direction of the external tangential momentum input, substantial changes in not only toroidal but also poloidal flows for the carbon impurity ions are observed at around the 
-well region. The shear in the edge becomes wider in the co-NBI case, while the edge -well becomes deeper in the counter-NBI case.
Oyama, Naoyuki; Shinohara, Koji; Isayama, Akihiko; Yoshida, Maiko; Kamiya, Kensaku
Purazuma, Kaku Yugo Gakkai-Shi, 88(5), p.282 - 285, 2012/05
no abstracts in English
