[Table of Contents]

Plasma and Fusion Research

Volume 5, S2016 (2010)

Regular Articles

Nonlinear Mode Couplings in a Cylindrical Magnetized Plasma
Takuma YAMADA, Sanae-I. ITOH1), Shigeru INAGAKI1), Yoshihiko NAGASHIMA, Shunjiro SHINOHARA2), Naohiro KASUYA3), Kenichiro TERASAKA2), Kunihiro KAMATAKI1), Hiroyuki ARAKAWA2), Masatoshi YAGI1), Akihide FUJISAWA1) and Kimitaka ITOH3)
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
1)
Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan
2)
Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga 816-8580, Japan
3)
National Institute for Fusion Science, Toki 509-5292, Japan
(Received 9 December 2009 / Accepted 11 February 2010 / Published 10 December 2010)

Abstract

Nonlinear mode couplings in plasma turbulence generate mesoscale global structures, such as zonal flows and streamers. A streamer is a poloidally localized structure that is radially elongated. In the Large Mirror Device-Upgrade, a streamer structure was observed in the ion saturation-current fluctuation measured with a 64-channel poloidal Langmuir probe array. The bunching of waves was poloidally localized and rotated slowly in the ion diamagnetic direction. The frequency and poloidal mode number of its envelope corresponded to one particular mode, which was strongly coupled with many other modes. By calculating the radial biphase profile of three pronounced modes, including the particular mode, the streamer structure was confirmed to be radially elongated.

Keywords

linear plasma, turbulence, nonlinear coupling, streamer, bispectral analysis

DOI: 10.1585/pfr.5.S2016

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This paper may be cited as follows:

Takuma YAMADA, Sanae-I. ITOH, Shigeru INAGAKI, Yoshihiko NAGASHIMA, Shunjiro SHINOHARA, Naohiro KASUYA, Kenichiro TERASAKA, Kunihiro KAMATAKI, Hiroyuki ARAKAWA, Masatoshi YAGI, Akihide FUJISAWA and Kimitaka ITOH, Plasma Fusion Res. 5, S2016 (2010).