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Konovalov, S. V.; Mikhailovskii, A. B.*; Ozeki, Takahisa; Takizuka, Tomonori; Shirokov, M. S.*; Hayashi, Nobuhiko
Plasma Physics and Controlled Fusion, 47(12B), p.B223 - B236, 2005/12
Times Cited Count：7 Percentile：24.62(Physics, Fluids & Plasmas)Neoclassical Tearing Modes, NTMs, are known to limit the maximum attainable plasma pressure, degrade confinement and, at worst, culminate in disruption of the tokamak discharges. Key role in NTM evolution belongs to the radial profiles of the plasma flow, temperature and density which are determined by the conjunction of the longitudinal and cross-filed transport arising from thermal conduction, particle diffusion, and viscosity. In this report the influence of anomalous perpendicular heat transport and anomalous ion perpendicular viscosity on early stage of the NTM evolution is studied theoretically.
Konoshima, Shigeru; Peterson, B. J.*; Ashikawa, Naoko*; Miura, Yukitoshi; JT-60 Team
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
An IR imaging bolometer with semi-tangential views of the diverted tokamak has been designed and installed in JT-60U in 2003-2004. A 2.5 microns gold absorber foil of 9 cm 
7 cm was shown to be durable during two years of operation with 1800 tokamak discharges including disruptions. Some unique analog video data from the IR camera characterizing diverted tokamak discharges have been obtained during test operation. A radiating toroidal ring has been mapped and recorded onto the foil as a clear high temperature zone at the disruption, consistent with huge core radiation measured by the resistive bolometers. Divertor radiation near the W-shaped divertor tiles of JT-60U could be identified also in the foil image as a thick line having toroidal curvature.
Owaki, Hirokazu; Sugihara, Masayoshi; Kawano, Yasunori; Lukash, V. V.*; Khayrutdinov, R. R.*; Zhogolev, V.*; Ozeki, Takahisa; Hatayama, Akiyoshi*
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
no abstracts in English
Sato, Masayasu; Isayama, Akihiko; Inagaki, Shigeru*; Nagayama, Yoshio*; Kawahata, Kazuo*; Iwama, Naofumi*
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
no abstracts in English
spectral bands for hydrocarbon-loss-events measured in JT-60U divertor plasmasNakano, Tomohide; Tsuzuki, Kazuhiro; Higashijima, Satoru; Kubo, Hirotaka; Asakura, Nobuyuki
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
Emission rates of CH and C
spectral bands for CH
, CD
_2
loss events due to dissociation, ionization and transport were measured in JT-60U divertor plasmas. The obtained data were used for estimating the chemical sputtering yields by a spectroscopic technique. The CH loss events over one CH photon emission was about 200 at electron temperatures between 30 eV and 70 eV. These values fell within the confidential band of the CD one. The CH
loss events over one CH and one C photon emission were, respectively, between 200 - 300 and between 600 - 1800, and their ratio between 3 - 6. On the assumption that only CH among hydrocarbons generated by chemical sputtering emits the C spectral bands, the intensity of the CH spectral bands originating from CH is inferred from the intensity of C spectral bands multiplied by the obtained ratio, resulting in higher than the measured CH intensity. This result indicates that dominant hydrocarbons generated by the chemical sputtering is not CH but CH.
Hamamatsu, Kiyotaka; Takizuka, Tomonori; Hayashi, Nobuhiko; Ozeki, Takahisa
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
no abstracts in English
Kikuchi, Mitsuru; Suzuki, Takahiro; Sakamoto, Yoshiteru; Fujita, Takaaki; Naito, Osamu; JT-60 Team
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
Until 1995, it is experimentally confirmed that parallel transport of tokamak follows prediction of neoclassical theory (Kikuchi, Azumi, PPCF review). But it relies on gloval parameter. Since then, local measurement of bootstrap current density or electrical conductivity becomes possible by the development of new plasma diagnostics technique. In this paper, method of comparison of current profile evaluation and its application to electrical conductivity and bootstrap current density is reported.
Kawano, Yasunori; Nakano, Tomohide; Isayama, Akihiko; Hatae, Takaki; Konoshima, Shigeru; Oyama, Naoyuki; Kondoh, Takashi; Tamai, Hiroshi; Kubo, Hirotaka; Asakura, Nobuyuki; et al.
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
In order to mitigate the post-disruption runaway electrons, experiments has been carried out with impurity pellet injection. As a result, we have observed the prompt exhaust of the runaway electrons and the reduction of runaway plasma. We have presented one possible explanation for basic behavior of the runaway plasma current that it follows the balance of the avalanche generation of runaway electrons and their slowing down predicted by the model, including effects by synchrotron radiation. On the other hand, standing on the fact that the current quench time is extended by runaway electrons, the experiment for avoiding the current quench by runaway electrons has been carried out. The runaway electrons reinforced the discharge to survive against the low Te of less than several tens eV and an additional impurity pellet injection, and thus the plasma current was maintained and terminated as programmed. To study the dynamics of runaway electrons precisely, a new active and direct diagnostic concept using the laser inverse Compton scattering has been proposed.
Idomura, Yasuhiro; Kishimoto, Yasuaki; Tokuda, Shinji
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
A gyrokinetic simulation is an essential tool to study anomalous turbulent transport in tokamak plasmas. Although a delta-f PIC code or a particle approach has been a standard method, it has difficulty in implementing non-conservative effects such as a heat source and collisions, which are important for a realistic long time turbulence simulation. On the other hand, a Vlasov code or a mesh approach is much more flexible to simulate these non-conservative effects. In this work, a new gyrokinetic Vlasov code is developed based on the CIP method, which is one of recent advanced CFD schemes. Numerical properties and computational costs of the gyrokinetic PIC and CIP codes are compared in ITG turbulence simulations.
Takenaga, Hidenobu; Oyama, Naoyuki; Isayama, Akihiko; Inagaki, Shigeru*; Takizuka, Tomonori; Fujita, Takaaki; Miura, Yukitoshi
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
no abstracts in English
