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Sato, Satoshi*; Kwon, Saerom*; Ota, Masayuki*; Ochiai, Kentaro*; Konno, Chikara
Proceedings of 26th IAEA Fusion Energy Conference (FEC 2016) (CD-ROM), 8 Pages, 2016/10
In the integral experiments on tungsten, vanadium and copper performed with the DT neutron source at JAEA/FNS over 20 years ago, the calculated results had largely underestimated the measured ones sensitive to low energy neutrons in the experiments. Since background neutrons scattered in the concrete wall of the experimental room were considered to cause these underestimations, in this study we performed new integral experiments with these materials covered with Li
O blocks absorbing background neutrons. We also performed similar integral experiments on molybdenum and titanium. We analyzed these experiments by using MCNP5-1.40 with ENDF/B-VII.1, JEFF-3.2 and JENDL-4.0. The large underestimations observed in the previous tungsten and vanadium experiments disappeared in the present experiments, which led that the nuclear data of tungsten and vanadium had no problem. On the other hand, the underestimation was not improved so much in the copper experiment, and the calculation results also did not show good agreements with the measured ones in the molybdenum and titanium experiments. Detailed analyses with partly modified nuclear data clarified the problems of the nuclear data libraries on copper, molybdenum and titanium.
Matsuoka, Seikichi; Idomura, Yasuhiro; Satake, Shinsuke*
no journal, ,
Effects of non-axisymmetric magnetic field perturbations have attracted much attention from the view point of the control of the plasma performance and instabilities. Recent studies pointed out that the qualitative discrepancy of the NTV prediction exist between a theoretical bounce-averaged model and a global kinetic simulation. It is crucial to clarify the cause of the discrepancy to establish a reliable basis for the NTV predictions. In this work, we perform two types of global kinetic simulations for the NTV to investigate the discrepancy from the theoretical model. As a result, it is first demonstrated that the discrepancy arises owing to the following two mechanisms; (1) resonant structures predicted in the bounce-averaged model disappear due to the large particle orbit in the global kinetic simulations, and (2) fine scale structures are generated in the velocity space in the global kinetic simulations.
Idomura, Yasuhiro; Asahi, Yuichi*; Hayashi, Nobuhiko*; Urano, Hajime*
no journal, ,
Full-f gyrokinetic simulations are important tools for analyzing nonlocal turbulent transport, plasma profiles, and the confinement time in fusion plasmas. However, the conventional full-f simulations were limited to ion turbulence with adiabatic electrons. In order to analyze ITER relevant electron turbulence, in this work, we develop a new hybrid electron model for full-f simulations, and verify its accuracy. In the model, passing electrons responses, which induce high frequency noises, are approximated by analytic solutions, and long time scale full-f simulations are enabled by eliminating the high frequency noises. Numerical experiments of electron turbulence using this model clarify new mechanisms for turbulence suppression and momentum transport related to electron turbulence transport. In a validation study, an experimental observation on plasma rotation changes induced by electron heating is successfully reproduced.