[Table of Contents]

Plasma and Fusion Research

Volume 2, 031 (2007)

Rapid Communications

A Study on Low-Frequency Fluctuations Using New Azimuthal Probe Array in High-Density Helicon Linear Plasma
Kenichiro TERASAKA, Shunjiro SHINOHARA , Yoshihiko NAGASHIMA1), Takuma YAMADA1), Masato KAWAGUCHI, Takashi MARUTA, Shigeru INAGAKI1), Yoshinobu KAWAI1), Naohiro KASUYA2), Masatoshi YAGI1), Akihide FUJISAWA2), Kimitaka ITOH2) and Sanae-I. ITOH1)
Interdisciplinary Graduate School of Engineering Sciences, Kyushu University
1)
Research Institute for Applied Mechanics, Kyushu University
2)
National Institute for Fusion Science
(Received 28 April 2007 / Accepted 12 June 2007 / Published 11 July 2007)

Abstract

In a high-density plasma produced by helicon waves in a linear device, a change from the coherent to broad-band density fluctuations was observed on increasing the magnetic field. The coherent mode exhibited the drift wave features, and a steady oscillation state was observed. When the magnetic field was increased, the fluctuation level increased, and the higher azimuthal Fourier components were excited. When the spectrum became broad at the higher magnetic field, the behavior of the azimuthal structure became complex and changed rapidly with time. The analysis performed using the movable probe array (48ch.-probe) decomposed the short-lived structure into poloidal mode-frequency space and indicated mode-mode coupling in the broad-band spectrum.

Keywords

drift wave, turbulence, probe array, wavenumber-frequency spectrum, helicon plasma

DOI: 10.1585/pfr.2.031

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This paper may be cited as follows:

Kenichiro TERASAKA, Shunjiro SHINOHARA , Yoshihiko NAGASHIMA, Takuma YAMADA, Masato KAWAGUCHI, Takashi MARUTA, Shigeru INAGAKI, Yoshinobu KAWAI, Naohiro KASUYA, Masatoshi YAGI, Akihide FUJISAWA, Kimitaka ITOH and Sanae-I. ITOH, Plasma Fusion Res. 2, 031 (2007).