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Kawano, Yasunori; Akiyama, Tsuyoshi*; Ishikawa, Masao; Isobe, Mitsutaka*; Itami, Kiyoshi; Ejiri, Akira*; Peterson, B.*
Purazuma, Kaku Yugo Gakkai-Shi, 92(2), P. 145, 2016/02
no abstracts in English
Imazawa, Ryota; Kawano, Yasunori; Ono, Takehiro; Itami, Kiyoshi
Review of Scientific Instruments, 87(1), p.013503_1 - 013503_7, 2016/01
Times Cited Count:4 Percentile:23.84(Instruments & Instrumentation)no abstracts in English
Yamamoto, Tsuyoshi; Hashimoto, Yasunori*; Kitazawa, Sin-iti; Yatsuka, Eiichi; Hatae, Takaki; Sugie, Tatsuo; Ogawa, Hiroaki; Takeuchi, Masaki; Kawano, Yasunori; Itami, Kiyoshi
Fusion Engineering and Design, 96-97, p.1012 - 1016, 2015/10
Times Cited Count:4 Percentile:36.12(Nuclear Science & Technology)Japan Domestic Agency (JADA) is responsible for six diagnostic systems in the ITER project. We have successfully developed an instrumentation and control (I&C) system for the diagnostic systems. The I&C system manages internal operations for measurement such as health checks of sensors, configuration of measurement parameters, and consistency checks between measurement parameters. We developed a conversion tool to convert operational flowcharts to EPICS records. The sequencing management function coordinates the execution of operation steps by monitoring changes in the record values. It was designed so that the relationship between the records and steps is determined automatically according to the flowcharts as much as possible. We validated the performance of the I&C system for the thermocouple measurement system, and are continuing the development of even more complex I&C systems for other JADA diagnostic systems.
Kawano, Yasunori; Akiyama, Tsuyoshi*; Ishikawa, Masao; Isobe, Mitsutaka*; Itami, Kiyoshi; Ejiri, Akira*; Peterson, B.*
Purazuma, Kaku Yugo Gakkai-Shi, 91(8), P. 565, 2015/08
no abstracts in English
Imazawa, Ryota; Kawano, Yasunori; Itami, Kiyoshi
Journal of Computational Physics, 292, p.208 - 214, 2015/07
Times Cited Count:5 Percentile:37.31(Computer Science, Interdisciplinary Applications)no abstracts in English
Kawano, Yasunori; Akiyama, Tsuyoshi*; Ishikawa, Masao; Isobe, Mitsutaka*; Itami, Kiyoshi; Ejiri, Akira*; Peterson, B. J.*
Purazuma, Kaku Yugo Gakkai-Shi, 91(1), P. 76, 2015/01
no abstracts in English
Imazawa, Ryota; Kawano, Yasunori; Itami, Kiyoshi
Purazuma, Kaku Yugo Gakkai-Shi, 90(11), p.743 - 747, 2014/11
no abstracts in English
Imazawa, Ryota; Kawano, Yasunori; Itami, Kiyoshi
Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 6 Pages, 2014/10
no abstracts in English
Sasao, Hajime; Arakawa, Hiroyuki*; Kubo, Hirotaka; Kawano, Yasunori; Itami, Kiyoshi
Review of Scientific Instruments, 85(8), p.086106_1 - 086106_3, 2014/08
Times Cited Count:2 Percentile:11.99(Instruments & Instrumentation)Kawano, Yasunori; Akiyama, Tsuyoshi*; Ishikawa, Masao; Isobe, Mitsutaka*; Itami, Kiyoshi; Ejiri, Akira*; Peterson, B.*
Purazuma, Kaku Yugo Gakkai-Shi, 90(7), P. 431, 2014/07
no abstracts in English
Shibata, Yoshihide; Isayama, Akihiko; Matsunaga, Go; Kawano, Yasunori; Miyamoto, Seiji*; Lukash, V.*; Khayrutdinov, R.*; JT-60 Team
Plasma and Fusion Research (Internet), 9(Sp.2), p.3402084_1 - 3402084_5, 2014/06
We performed the disruption simulation using DINA code to investigate the effect of the electron temperature on the plasma current decay after the initial phase of current quench (CQ). In this calculation, we used the measured
profile during the initial phase of CQ. After the initial phase of CQ, we assumed that the
profile does not change in time and used the value at the end of the initial phase of current quench because
profile could not be measured after the initial phase of CQ. From the simulation results, it was found that the time evolution of plasma current calculated by DINA was similar to experimental one in this calculation. However, the time evolution of
profile in this calculation was different from the measured
profile because Te after first mini-collapse rapidly decreased until the value below a measurement limit (less than 0.1 keV). Moreover, the time evolution of poloidal cross-section S calculated by DINA code was rapidly decreased although the experimental one was gradually decreased. The plasma current decay during the disruption is determined by various parameters,
,
and S. It is necessary to evaluate the effect of
profile on the plasma current decay after the initial phase of CQ by using various assumed
model and DINA code.
Yamamoto, Tsuyoshi; Hashimoto, Yasunori*; Serizawa, Yasunori*; Inamoto, Shuji*; Sato, Kazuyoshi; Sugie, Tatsuo; Takeuchi, Masaki; Kawano, Yasunori
Fusion Engineering and Design, 89(5), p.532 - 535, 2014/05
Times Cited Count:1 Percentile:9.57(Nuclear Science & Technology)The diagnostic systems are essential for the plasma control and physics understandings. JAEA has proposed the new concept of supervisory system which manages operation sequences, current state and configuration parameters for the measurement based on our experiences in operating plasma diagnostic systems. We designed the supervisory system satisfying the requirements from both CODAC system and diagnostic systems. In our design, the tool which converts operational steps described as flowcharts into EPICS Records templates is introduced. This tool will ensure reduction of the system designers' efforts. We also designed the sequencing simulator that can submit transition commands internally instead of CODAC system for the calibration and commissioning. The mechanism which changes the limit values and consistency check algorithms in accordance with the conditions of the diagnostics system is also proposed.
Kitazawa, Sin-iti; Yamamoto, Tsuyoshi; Kawano, Yasunori; Itami, Kiyoshi
Plasma and Fusion Research (Internet), 9(Sp.2), p.3405049_1 - 3405049_4, 2014/05
The Japan Domestic Agency (JADA) is scheduled to procure a divertor thermocouple (DTC) system for the divertor outer vertical targets in the ITER project. The DTC is a diagnostic device that will directly measure the surface temperature of the divertor, a plasma-facing component, and will be installed on the surface of the divertors which are in the scope of JADA procurement sharing. A thermocouple itself is a conventional device used for measuring temperature, however, for the DTC to be able to take highly reliable operation under the ultrahigh vacuum and high radiation field of the ITER environment. Therefore various advanced research and development is necessary. Development of the DTC control system, which is based on ITER standards, should also be performed since it is included within the scope of JADA procurement. In this presentation, we will show the current status of research & development on the DTC.
Shibata, Yoshihide; Isayama, Akihiko; Miyamoto, Seiji*; Kawakami, Sho*; Watanabe, Kiyomasa*; Matsunaga, Go; Kawano, Yasunori; Lukash, V.*; Khayrutdinov, R.*; JT-60 Team
Plasma Physics and Controlled Fusion, 56(4), p.045008_1 - 045008_8, 2014/04
Times Cited Count:2 Percentile:11.29(Physics, Fluids & Plasmas)In JT-60U disruption, the plasma current decay during the initial phase of current quench has been calculated by a disruption simulation code (DINA) using the measured electron temperature profile. In the case of fast plasma current decay,
has a peaked profile just after thermal quench and the
profile doesn't change significantly during the initial phase of current quench. On the other hand, in the case of the slow plasma current decay, the
profile is border just after the thermal quench, and the
profile shrinks. The results of DINA simulation show that plasma internal inductance
increases during the initial phase of current quench, while plasma external inductance
does not change in time. The increase of
is caused by current diffusion toward the core plasma due to the decrease of
in intermediate and edge regions. It is suggested that an additional heating in the plasma periphery region has the effect of slowing down plasma current decay.
Kawano, Yasunori; Itami, Kiyoshi; Kawahata, Kazuo*; Kusama, Yoshinori; Sasao, Mamiko*; Peterson, B.*; Mase, Atsushi*
Purazuma, Kaku Yugo Gakkai-Shi, 90(2), P. 164, 2014/02
no abstracts in English
Imazawa, Ryota; Kawano, Yasunori; Itami, Kiyoshi; Kusama, Yoshinori
Nuclear Fusion, 54(1), p.013012_1 - 013012_8, 2014/01
Times Cited Count:0 Percentile:0.01(Physics, Fluids & Plasmas)This paper proposes a new method to calculate a safety factor, , profile from gridded data of a poloidal flux,
, efficiently and accurately. Difficulties of calculating
are derived from a difficulty of specifying a contour line of
and a singularity at a magnetic axis. In order to solve the first difficulty, the proposed method interpolates knots, which are located on a target
, by utilizing a normalized arc length and constraints expressed by a magnetic field. Regarding the second difficulty, the proposed method identifies
by extrapolating
profile around a magnetic axis with a constraint of
at the magnetic axis. Accuracy assessments of the proposed method are carried out by utilizing Solov'ev type equilibrium. The results show the validity and high performance of the proposed method.
Kawakami, Sho*; Shibata, Yoshihide; Watanabe, Kiyomasa*; Ono, Noriyasu*; Isayama, Akihiko; Takizuka, Tomonori*; Kawano, Yasunori; Okamoto, Masaaki*
Physics of Plasmas, 20(11), p.112507_1 - 112507_6, 2013/11
Times Cited Count:2 Percentile:9.46(Physics, Fluids & Plasmas)According to an early work on the behavior of the plasma current decay in the JT-60U disruptive discharges caused by the radiative collapse with a massive neon-gas-puff, the increase of the internal inductance mainly determined the current decay time of plasma current during the initial phase of current quench. To investigate what determines the increase of the internal inductance, we focus attention on the relationship between the electron temperature (or the resistivity) profile and the time evolution of the current density profile, and carry out numerical calculations. As a result, we find the reason of the increase of the internal inductance: The current density profile at the start of the current quench is broader than an expected current density profile in the steady state, which is determined by the temperature (or resistivity) profile. The current density profile evolves into peaked one and the internal inductance is increasing.
Itami, Kiyoshi; Kawano, Yasunori; Kawahata, Kazuo*; Kusama, Yoshinori; Sasao, Mamiko*; Peterson, B.*; Mase, Atsushi*
Purazuma, Kaku Yugo Gakkai-Shi, 89(9), P. 638, 2013/09
no abstracts in English
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:18.89(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.
Imazawa, Ryota; Kawano, Yasunori; Kusama, Yoshinori
Review of Scientific Instruments, 83(12), p.123507_1 - 123507_5, 2012/12
Times Cited Count:4 Percentile:22.85(Instruments & Instrumentation)no abstracts in English