Exploration of spontaneous vortex formation and intermittent behavior in ECR plasmas: The HYPER-I experiments

S. Yoshimura, Kenichiro Terasaka, E. Tanaka, M. Aramaki, A. Okamoto, K. Nagaoka, Masayoshi Tanaka

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    Abstract

    HYPER-I (High Density Plasma Experiment-I) is a linear device that combines a wide operation range of plasma production with flexible diagnostics. The plasmas are produced by the electron cyclotron resonance (ECR) heating with parallel injection of right-handed circularly polarized microwaves of 2.45 GHz from the high-field side. The maximum attainable electron density is more than two orders of magnitude higher than the cutoff density of ordinary waves. Spontaneous formation of a variety of large-scale flow structures, or vortices, has been observed in the HYPER-I plasmas. Flow-velocity field measurements using directional Langmuir probes (DLPs) and laser-induced fluorescence (LIF) method have clarified the physical processes behind such vortex formations. Recently, a new intermittent behavior of local electron temperature has also been observed. Statistical analysis of the floating potential changes has revealed that the phenomenon is characterized by a stationary Poisson process.

    Original languageEnglish
    Article number00114
    JournalJournal of Plasma Physics
    Volume81
    Issue number2
    DOIs
    Publication statusPublished - Apr 30 2015

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    All Science Journal Classification (ASJC) codes

    • Condensed Matter Physics

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