Fluctuation measurement across the broad range of the low-field side edge plasmas in the TST-2 spherical tokamak

Masateru Sonehara, Yoshihiko Nagashima, Yuichi Takase, Akira Ejiri, Takashi Yamaguchi, Takanori Ambo, Hidetoshi Kakuda, Junichi Hiratsuka, Takuya Sakamoto, Ryota Shino, Takuma Wakatsuki, Osamu Watanabe

    Research output: Contribution to journalArticlepeer-review

    Abstract

    This paper presents initial results from experimental observation of edge turbulence structures in ohmically heated plasmas on Tokyo Spherical Tokamak-2 (TST-2). The experiment was conducted using two-dimensionally movable Langmuir probes. With monitoring floating potential V f and ion saturation current I is, the radial and poloidal structures of the edge turbulence are obtained. The high coherence in fluctuations at 10-100kHz frequency was observed by the use of the Langmuir probes 90° toroidally and ∼75° poloidally distant from each other, suggesting that the fluctuations have long range correlation along a magnetic field line. To investigate nonlinear structures of the turbulence, bispectral analysis was used, and the observed auto-bicoherence pattern suggests the presence of the coupling and energy transfer between different modes.

    Original languageEnglish
    Pages (from-to)499-504+7
    JournalIEEJ Transactions on Fundamentals and Materials
    Volume132
    Issue number7
    DOIs
    Publication statusPublished - 2012

    All Science Journal Classification (ASJC) codes

    • Electrical and Electronic Engineering

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