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Wakai, Eiichi; Watanabe, Kazuyoshi*; Ito, Yuzuru*; Suzuki, Akihiro*; Terai, Takayuki*; Yagi, Juro*; Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; et al.
Plasma and Fusion Research (Internet), 11, p.2405112_1 - 2405112_4, 2016/11
Nishikiori, Ryo; Kojima, Atsushi; Hanada, Masaya; Kashiwagi, Mieko; Watanabe, Kazuhiro; Umeda, Naotaka; Tobari, Hiroyuki; Yoshida, Masafumi; Ichikawa, Masahiro; Hiratsuka, Junichi; et al.
Plasma and Fusion Research (Internet), 11, p.2401014_1 - 2401014_4, 2016/03
One of critical issues for high-energy high-current beam acceleration in ITER and JT-60SA is the high voltage holding which is dominated by vacuum discharges. The past results suggest that vacuum discharge occurs beyond the threshold of the dark current. The dark current can be derived from F-N theory where electric field enhancement factor beta is included. Though, beta could only be evaluated from the experiment previously. Therefore, the method to decide beta without experiment is required. This time dark currents were measured at three different areas to compare beta in different electric field. As a result, the effective electric field 
E, where E is average electric field, were found to be almost constant for different areas although the beta is largely different. By applying E, beta can be evaluated analytically, leading to the analytical prediction of the dark current and voltage holding capability without the measurements.
Idomura, Yasuhiro
Plasma and Fusion Research (Internet), 11, p.2403006_1 - 2403006_5, 2016/02
In this work, we address saturation mechanisms of decaying turbulence induced by the ion temperature gradient driven trapped electron mode. In the simulation, turbulent transport is quenched in the nonlinear quasi-steady phase, where temperature profiles exceeding linear critical temperature gradient parameters are formed. This kind of nonlinear critical temperature gradient is sustained by radial electric fields with strong shear, which is generated by corrugated density profiles. It is found that the density profile structure is related to electrons transport near low order mode rational surfaces, where non-adiabatic response of passing electrons becomes important.
Wakatsuki, Takuma; Suzuki, Takahiro; Hayashi, Nobuhiko; Shiraishi, Junya; Ide, Shunsuke; Kubo, Hirotaka; Takase, Yuichi*
no journal, ,
Yamamoto, Tsuyoshi; Yatsuka, Eiichi; Hatae, Takaki; Ota, Kazuya*; Hashimoto, Yasunori*; Nakamura, Kitaru*; Sugie, Tatsuo*; Takeuchi, Masaki; Kitazawa, Sin-iti; Ogawa, Hiroaki; et al.
no journal, ,
ITER edge Thomson scattering system (ETS) is being developed in Japan. ETS measures electron density and temperature profiles using high energy laser more than 5 J. Therefore, ETS has to contain interlock system to protect optical components from damage caused by laser malfunctions. As same as interlock system, conventional control also should sustain components good conditions. We proposed new method that templates for program codes of conventional control were generated from interlock logics using information technologies such as semantic web technique. In addition, we applied the plant description data to risk analysis. HAZOP (hazard and operability study) is a useful method to indentify hazards and problems in a system. To describe plant functionalities and behaviors using ontology for functional knowledge, list of possible risks are extracted from the description by applying substitution and/or inference rules.
Kasugai, Atsushi
no journal, ,
The Accelerator Facility is being validated with the Linear IFMIF Prototype Accelerator (LIPAc). LIPAc is demonstrating the feasibility of the low energy section of an IFMIF deuteron accelerator up to 9 MeV with a beam current of 125 mA in CW at IFERC of JAEA in Rokkasho, Japan. The deuterium ion beam injector is under commissioning. At this stage, a 100keV/120mA/CW hydrogen ion beam and 100keV/90mA/CW deuteron ion beam have been produced with a low beam emittance of 0.21 
mm mrad (rms, normalized) and mass fractions above 90%. Delivery of RFQ components, consisting of RFQ accelerator developed by INFN in Italy and RF power supplies developed by CIEMAT in Spain is under way, followed by the installation of RF power supplies scheduled for this year as well. After the commissioning of the injector, RFQ, MEBT, D-Plate, HEBT, beam dump and SRF linac will be installed and tested in step by step approach.
