Experimental Study of Nonlinear Processes in Edge Turbulence of Toroidal Plasmas
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- NAGASHIMA Yoshihiko
- Research Institute for Applied Mechanics, Kyushu University
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- HOSHINO Katsumichi
- Japan Atomic Energy Agency
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- NAGAOKA Kenichi
- National Institute for Fusion Science
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- SHINOHARA Kouji
- Japan Atomic Energy Agency
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- FUJISAWA Akihide
- National Institute for Fusion Science
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- UEHARA Kazuya
- Japan Atomic Energy Agency
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- KUSAMA Yoshinori
- Japan Atomic Energy Agency
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- IDA Katsumi
- National Institute for Fusion Science
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- YOSHIMURA Yasuo
- National Institute for Fusion Science
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- OKAMURA Shoichi
- National Institute for Fusion Science
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- MATSUOKA Keisuke
- National Institute for Fusion Science
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- EJIRI Akira
- University of Tokyo
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- TAKASE Yuichi
- University of Tokyo
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- ITOH Kimitaka
- National Institute for Fusion Science
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- YAGI Masatoshi
- Research Institute for Applied Mechanics, Kyushu University
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- ITOH Sanae-I.
- Research Institute for Applied Mechanics, Kyushu University
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- JFT-2M group
- Japan Atomic Energy Agency
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- CHS group
- National Institute for Fusion Science
Abstract
This paper presents experimental studies of nonlinear processes between meso-scale structures and turbulent fluctuations, by use of bispectral analysis, in the edge region of toroidal plasmas. In ohmically heated plasmas of the JFT-2M tokamak, the drift wave-zonal flow system is investigated by observation of the potential fluctuations. The total bicoherence is composed of two components, i.e., the peak at the geodesic acoustic mode (GAM) frequency and broadband distribution. The biphase is also obtained, which indicates the phase angle of coherent interaction between GAM oscillations and broadband fluctuations. Bispectral functions (e.g., magnitude and phase) give an order-of-estimate agreement for the drift wave-zonal flow systems. Bicoherence analysis is also applied to the edge plasmas of the high-confinement mode (H-mode) of the Compact Helical System (CHS). In the case of CHS plasmas, nonlinear couplings in a system composed of coherent global magneto-hydrodynamic (MHD) oscillations and broadband fluctuations (up to hundreds kHz range) have been observed. Bispectral analysis enhances our understanding of the self-regulation systems of various toroidal plasmas in which strong turbulence and meso-scale structures coexist.
Journal
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- Plasma and Fusion Research
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Plasma and Fusion Research 1 (0), 041-041, 2006
The Japan Society of Plasma Science and Nuclear Fusion Research
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Keywords
Details 詳細情報について
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- CRID
- 1390282680232609792
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- NII Article ID
- 130002058823
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- ISSN
- 18806821
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- Text Lang
- en
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- Data Source
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- JaLC
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed