Plasma and Fusion Research
Volume 8, 1402066 (2013)
Regular Articles
- Graduate School of Energy Science, Kyoto University, Uji, Kyoto 611-0011, Japan
- 1)
- Graduate School of Engineering, Hiroshima University, Higashihiroshima 739-8527, Japan
- 2)
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
- 3)
- Naka Fusion Institute, Japan Atomic Energy Agency, Naka 311-0193, Japan
- 4)
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
Abstract
A perpendicular-view fast video camera has been installed in Heliotron J to observe the behavior of filamentary structures of edge plasma turbulence across the last closed flux surface (LCFS). Supersonic molecular-beam injection (SMBI) can greatly increase the edge Hα emission; hence, we used the high imaging rate and shutter speed of the camera to capture the behavior of the fast propagating filamentary structures. A high-pass fast Fourier transform filter on the time dimension was adopted to extract the fluctuation component from the raw data for each pixel. The motion of the filamentary structures was clearly visible when we applied an amplitude threshold to identify the intense structures. In addition, a time-resolved 2D cross-correlation technique was adopted to estimate the poloidal phase velocity of turbulence. The motion direction was found to be reversed dramatically just after an SMBI pulse.
Keywords
filamentary structure, edge fluctuation, edge turbulence, fast camera, SMBI, LCFS, Heliotron J, poloidal velocity
Full Text
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This paper may be cited as follows:
Linge ZANG, Nobuhiro NISHINO, Tohru MIZUUCHI, Shinsuke OHSHIMA, Masaki TAKEUCHI, Keijun KASAJIMA, Mengyu SHA, Kiyofumi MUKAI, Hyunyong LEE, Kazunobu NAGASAKI, Hiroyuki OKADA, Takashi MINAMI, Shinji KOBAYASHI, Satoshi YAMAMOTO, Shigeru KONOSHIMA, Yuji NAKAMURA and Fumimichi SANO, Plasma Fusion Res. 8, 1402066 (2013).