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(EX/C4-5Ra) Response of Temperature and Density Profiles to Heat Deposition Profile and its Impact on Global Scaling in LHD

H. Yamada1), S. Murakami1), K. Yamazaki1), O. Kaneko1), J. Miyazawa1), R. Sakamoto1), K.Y. Watanabe1), K. Narihara1), K. Tanaka1), S. Sakakibara1), M. Osakabe1), B.J. Peterson1), S. Morita1), K. Ida1), S. Inagaki1), S. Masuzaki1), T. Morisaki1), G. Rewoldt2), H. Sugama1), N. Nakajima1), W.A. Cooper3), T. Akiyama4), N. Ashikawa1), M. Emoto1), H. Funaba1), P. Goncharov5), M. Goto1), H. Idei1), K. Ikeda1), M. Isobe1), K. Kawahata1), H. Kawazome6), K. Khlopenkov1), T. Kobuchi1), A. Komori1), A. Kostrioukov1), S. Kubo1), R. Kumazawa1), Y. Liang1), T. Minami1), S. Muto1), T. Mutoh1), Y. Nagayama1), Y. Nakamura1), H. Nakanishi1), Y. Narushima1), K. Nishimura1), N. Noda1), T. Notake7), H. Nozato8), S. Ohdachi1), N. Ohyabu1), Y. Oka1), T. Ozaki1), A. Sagara1), T. Saida5), K. Saito1), M. Sasao1), K. Sato1), M. Sato1), T. Seki1), T. Shimozuma1), M. Shoji1), H. Suzuki1), Y. Takeiri1), N. Takeuchi7), N. Tamura1), K. Toi1), T. Tokuzawa1), Y. Torii7), K. Tsumori1), T. Watanabe1), T. Watari1), Y. Xu1), I. Yamada1), S. Yamamoto7), T. Yamamoto7), M. Yokoyama1), Y. Yoshimura1), M. Yoshinuma1), T. Mito1), K. Itoh1), K. Ohkubo1), I. Ohtake1), T. Satow1), S. Sudo1), T. Uda1), K. Matsuoka1), O. Motojima1)
1) National Institute for Fusion Science, Toki, Gifu, Japan
2) Princeton Plasma Physics Laboratory, Princeton, NJ, USA
3) Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
4) Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo, Japan
5) Graduate University for Advanced Studies, Hayama, Japan
6) Graduate School of Energy Science, Kyoto University, Uji, Japan
7) Department of Energy Engineering and Science, Nagoya University, Nagoya, Japan
8) Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan

Abstract.  Significant density dependence of the energy confinement time as described in the ISS95 scaling has been demonstrated in the extended parameter regimes in LHD. However, recent experiments have indicated that this density dependence is lost at a certain density under specific conditions. This paper discusses the cause of this saturation and related characteristics of anomalous transport. The saturation of the energy confinement time is observed in the density ramp-up phase of NBI heated plasmas. In contrast to the global energy confinement time, the local heat conduction coefficient still indicates the temperature dependence which is a companion to the density dependence of the energy confinement time. The apparent contradiction between the global confinement and the local transport can be attributed to the change of the heat deposition profile. Through this study, the response of temperature and density profiles to the heat deposition profile is highlighted, which is contrasted to the concept of stiffness or profile consistency observed in tokamaks. The major anomalous transport models based on ITG/TEM and interchange/ballooning modes are assessed.

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IAEA 2003