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Journal Articles

Development of instrumentation and control systems for the ITER diagnostic systems in JADA

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:40.75(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.

Journal Articles

Effects of the radial electric field on the confinement of fast ions in ITER

Tani, Keiji*; Honda, Mitsuru; Oikawa, Toshihiro*; Shinohara, Koji; Kusama, Yoshinori; Sugie, Tatsuo

Nuclear Fusion, 55(5), p.053010_1 - 053010_15, 2015/05


 Times Cited Count:2 Percentile:11.3(Physics, Fluids & Plasmas)

The effects of a radial electric field (EF) on the losses of alpha particles and NBI fast ions in typical ITER operation scenarios for both error fields due to test blanket modules (TBMs) and toroidal field (TF) ripple were evaluated using an iterative method to execute an orbit-following Monte-Carlo code and a one-dimensional transport code. The EF effect on the loss of fast ions strongly depends on the operation scenario as well as on the error field. The electric field is very significant in the loss of fast ions in a 9MA ITER operation scenario with a higher safety factor and in the error field associated with TBMs. The EF effect in the error field of TF-ripple is very small in any operation scenario. The radial electric field changes the toroidal precession of fast ions and consequently alter their condition of resonance with the error field, which may account for the EF effect on the loss of fast ions in ITER with TBMs.

Journal Articles

Development of the supervisory systems for the ITER diagnostic systems in JADA

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:10.7(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.

Journal Articles

Development of divertor IR thermography for ITER

Takeuchi, Masaki; Sugie, Tatsuo; Ogawa, Hiroaki; Ishikawa, Masao; Shimada, Takahiko; Kusama, Yoshinori

Plasma and Fusion Research (Internet), 8(Sp.1), p.2402147_1 - 2402147_5, 2013/11

Divertor IR Thermography is one of the diagnostics which Japan is in charge of development in ITER project. The conceptual design has been performed so far, and the progress is reported here. By reducing the size of mirrors, and making the optical path a labyrinthine structure, the design of a new optics that fills requirements of both spatial resolution and neutron shielding has been advanced. To achieve the required measurement accuracy, the detected signal and the noises such as bremsstrahlung light, detector noise and thermal noise of optical components were evaluated. Higher photons than the bremsstrahlung light are obtained, excluding the low temperature range. The simulation calculation of reflection from wall was started. Detailed method of data processing of deriving the profiles of surface temperature in the divertor plates from the observed signals and in-situ calibration strategies of the optical system are important issues and will be discussed.

Journal Articles

Designing a prototype of the ITER pulse scheduling system

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:20.56(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.

Journal Articles

Simulation of VDE under intervention of vertical stability control and vertical electromagnetic force on the ITER vacuum vessel

Miyamoto, Seiji; Sugihara, Masayoshi*; Shinya, Kichiro*; Nakamura, Yukiharu*; Toshimitsu, Shinichi*; Lukash, V. E.*; Khayrutdinov, R. R.*; Sugie, Tatsuo; Kusama, Yoshinori; Yoshino, Ryuji*

Fusion Engineering and Design, 87(11), p.1816 - 1827, 2012/11

 Times Cited Count:11 Percentile:69.17(Nuclear Science & Technology)

JAEA Reports

Bi-directional reflectance distribution function of a tungsten block for ITER divertor

Iwamae, Atsushi*; Ogawa, Hiroaki; Sugie, Tatsuo; Kusama, Yoshinori

JAEA-Research 2011-045, 11 Pages, 2012/02


In order to investigate reflection properties on plasma-facing material in ITER, the bi-directional reflectance distribution function (BRDF) of a tungsten block sample has been measured. On the machining surface of the block, one-directional machining lines are engraved. Two laser diodes $$lambda$$652 nm and $$lambda$$473 nm were used to simulate H$$_{alpha}$$ and H$$_{beta}$$ emissions, respectively. The reflected light is affected by the machining surface. The reflected light traces a line when the incident light is injected in the perpendicular direction to the engraved line. On the other hand the reflected light traces an arc shape when the incident light is injected in the parallel direction to the engraved lines. Ray tracing simulation qualitatively explains the experimental results.

Journal Articles

Effects of ELM mitigation coils on energetic particle confinement in ITER steady-state operation

Tani, Keiji*; Shinohara, Koji; Oikawa, Toshihiro*; Tsutsui, Hiroaki*; Miyamoto, Seiji; Kusama, Yoshinori; Sugie, Tatsuo

Nuclear Fusion, 52(1), p.013012_1 - 013012_21, 2012/01

 Times Cited Count:30 Percentile:82.76(Physics, Fluids & Plasmas)

Journal Articles

Synthesized intensity of emission lines of hydrogen isotopes and impurities in the ITER divertor plasma

Iwamae, Atsushi; Sugie, Tatsuo; Ogawa, Hiroaki; Kusama, Yoshinori

Plasma Physics and Controlled Fusion, 53(4), p.045005_1 - 045005_17, 2011/04

 Times Cited Count:2 Percentile:11.76(Physics, Fluids & Plasmas)

Journal Articles

${it In-situ}$ spectral calibration method for the impurity influx monitor (divertor) for ITER using angled physical contact fibers

Iwamae, Atsushi; Ogawa, Hiroaki; Sugie, Tatsuo; Kusama, Yoshinori

Review of Scientific Instruments, 82(3), p.033502_1 - 033502_4, 2011/03

 Times Cited Count:3 Percentile:19.8(Instruments & Instrumentation)

Journal Articles

Journal Articles

Modeling of L-H/H-L transition in TSC simulation using JT-60U experimental data

Miyamoto, Seiji; Nakamura, Yukiharu*; Hayashi, Nobuhiko; Oyama, Naoyuki; Takenaga, Hidenobu; Sugie, Tatsuo; Kusama, Yoshinori; Yoshino, Ryuji

Proceedings of 36th European Physical Society Conference on Plasma Physics (CD-ROM), 4 Pages, 2009/07

The neutral dynamics including fueling, divertor pumping, charge exchange penetration, wall retention and so on would complicate the analysis of ITER plasma behavior such as H-L back transition during plasma current ramp-down. Recently, a relatively simple model of neutral dynamics was developed by us with TSC code to describe the plasma behavior during L-H and H-L transition phase. This model is compared with a JT-60U shot, in which it is possible to extract the effect of particle confinement change on neutral because H-mode discharge is switched on/off according to EC injection and thereby particle source density is kept constant during transition. It is shown that TSC simulation can account the behavior of neutral inferred from the experimental D$$_alpha$$ signal. It is concluded that this model is applicable to scenario development of the ITER.

Journal Articles

TSC simulation of ITER plasma termination scenario with stable H-L mode transition and avoidance of radiation collapse

Nakamura, Yukiharu*; Miyamoto, Seiji; Toshimitsu, Shinichi; Sugie, Tatsuo; Kusama, Yoshinori; Yoshino, Ryuji

Proceedings of 36th European Physical Society Conference on Plasma Physics (CD-ROM), 4 Pages, 2009/07

The ITER termination scenario from 15 MA to 1.5 MA (500 s $$<$$ t $$leq$$ 700 s) was reviewed by self-consistent simulations with the TSC code, comprised of newly developed D-T fuelling and pumping-out system. At 600 s, when the plasma current decreased to 10 MA, auxiliary NB heating was switched off to cease fusion $$alpha$$-heating. Simultaneously, the energy confinement switches H to L mode by intentionally removing the H mode pedestal of edge transport barrier. The H to L mode transition dynamics, ${it e.g.}$ reduction in the plasma density while building-up of in-vessel neutral gas, disappearance of the edge BS current and consequent jump in the internal inductance $$l_i(3)$$, were investigated to assess performance of the ITER pump-out system. It was newly shown that the forced H to L mode transition may trigger a radiation collapse, consequently terminating the discharge. It was also demonstrated that EC heating with 170 GHz O-mode wave after the H to L mode transition provides an effective control means to hedge risk of the radiation collapse.

Journal Articles

Engineering design and R&D of impurity influx monitor (divertor) for ITER

Ogawa, Hiroaki; Sugie, Tatsuo; Kasai, Satoshi*; Katsunuma, Atsushi*; Hara, Hirotsugu*; Takeyama, Norihide*; Kusama, Yoshinori

Fusion Engineering and Design, 83(10-12), p.1405 - 1409, 2008/12

 Times Cited Count:12 Percentile:65.48(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Development of the UV and visible impurity influx monitor (divertor) for ITER

Iwamae, Atsushi; Ogawa, Hiroaki; Sugie, Tatsuo; Kasai, Satoshi*; Kusama, Yoshinori

Proceedings of 18th International Toki Conference on Development of Physics and Technology of Stellarator/Heliotrons en route to Demo (ITC-18) (CD-ROM), p.450 - 453, 2008/12

Journal Articles

Spectroscopic measurement system for ITER divertor plasma; Impurity influx monitor (divertor)

Sugie, Tatsuo; Ogawa, Hiroaki; Kasai, Satoshi*; Kusama, Yoshinori

AIP Conference Proceedings 988, p.218 - 221, 2008/04

The detailed design of the Impurity Influx Monitor (divertor) has been carried out to provide the measurement capability in the harsh environment. The potential damaging effects for the first mirrors mounted close to the plasma are the formations of coatings of impurities and the deposition of the dust. Mitigating measures to minimize the degradation of their performance by these effects, such as changes in the reflectivity, are adopted: for example, the plasma is viewed through a small aperture, and baffle plates are inserted in front of the first mirrors. However, it will not be possible to prevent the degradation completely. It is important to know the change of the sensitivity of the optical systems. It is not feasible to install a light source in the vacuum chamber of ITER during operations and so an alternative method is needed. The in-situ calibration system using a micro retro-reflector array has been developed as a possible method.

Journal Articles

Development of impurity influx monitor (Divertor) for ITER

Ogawa, Hiroaki; Sugie, Tatsuo; Kasai, Satoshi; Katsunuma, Atsushi*; Hara, Hirotsugu*; Kusama, Yoshinori

Plasma and Fusion Research (Internet), 2, p.S1054_1 - S1054_4, 2007/11

no abstracts in English

Journal Articles

Development of collective Thomson scattering for alpha-particle diagnostic in burning plasmas

Kondoh, Takashi; Hayashi, Toshimitsu; Kawano, Yasunori; Kusama, Yoshinori; Sugie, Tatsuo

Plasma and Fusion Research (Internet), 2, p.S1111_1 - S1111_4, 2007/11

A diagnostic of fusion-generated alpha-particles is important to understand burning plasma physics, however, an effective measurement method has not yet been established. A collective Thomson scattering (CTS) diagnostic CO$$_{2}$$ laser is being developed to establish a diagnostic method of confined alpha-particles. To realize the CTS diagnostic, a high-repetition Transversely Excited Atmospheric (TEA) CO$$_{2}$$ has been developed. In order to obtain single-mode output, which is needed for the CTS diagnostic, seed laser is injected to the cavity with an unstable resonator. Using this technique, output energy of 17J with the frequency of 15 Hz has been achieved with single-mode output. These results gives a prospect for the CTS diagnostic on International Thermonuclear Experimental Reactor (ITER), which requires energy of 20 J with the repetition rate of 40 Hz. Proof-of-principle test is being performed with the improved laser system on the JT-60U tokamak.

Journal Articles

Progress in development of collective Thomson scattering diagnostic with high power CO$$_{2}$$ laser

Kondoh, Takashi; Kawano, Yasunori; Hatae, Takaki; Sugie, Tatsuo; Hayashi, Toshimitsu; Kusama, Yoshinori

NIFS-PROC-68, p.126 - 129, 2007/09

High power and high repetition CO$$_{2}$$ laser has been developed for collective Thomson scattering (CTS) diagnostic to establish a diagnostic method of confined $$alpha$$-particles in burning plasmas. Pulse energy of 17 J at a repetition rate of 15 Hz has been achieved in a single-mode operation. This result gives a prospect for the CTS diagnostic on International Thermonuclear Experimental Reactor (ITER), which requires energy of 20 J with repetition rate of 40 Hz. The laser injection test into the vacuum vessel of the JT-60U tokamak has been carried out to check the electric noise and stray signals of the receiver system using the new CO$$_{2}$$ laser without plasma. As a result, electrical noise has been decreased, however, stray signal due to multimode oscillation has been observed in about 30% of the pulses and a further improvement of the laser is needed.

Journal Articles

Report of meetings of ITPA (International Tokamak Physics Activity), 19

Sasao, Mamiko*; Kusama, Yoshinori; Kawano, Yasunori; Kawahata, Kazuo*; Mase, Atsushi*; Sugie, Tatsuo; Fujita, Takaaki; Fukuda, Takeshi*; Fukuyama, Atsushi*; Sakamoto, Yoshiteru; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 83(9), p.779 - 782, 2007/09

This is a report of highlights from 2007 spring meetings of seven Topical Groups (TG) of International Tokamak Physics Activity (ITPA). In each meeting, high priority issues in physics of International Thermonuclear Experimental Reactor (ITER) and other burning plasma experiments have been discussed and investigated. Twenty-seven scientists from Japan have participated in those meetings. Dates and places of the meetings are shown below. (1) Diagnostics TG: 26-30 March, Princeton (USA), (2) Transport Physics TG: 7-10 May, Lausanne (Switzerland), (3) Confinement Database and Modeling TG: 7-10 May, Lausanne (Switzerland), (4) Edge Pedestal Physics TG: 7-10 May, Garching (Germany) (5) Steady State Operation TG: 9-11 May, Daejeon (South Korea), (6)MHD TG: 21-24 May, San Diego (USA), (7) Scrape-off-layer and Divertor Physics TG: 7-10 May, Garching (Germany).

215 (Records 1-20 displayed on this page)