Plasma and Fusion Research

Volume 13, 3402087 (2018)

Regular Articles

Spectroscopic Measurements of Impurity Ion Toroidal and Poloidal Flow Velocities and Their Dependence on Vertical Magnetic Field in QUEST Toroidal ECR Plasmas
Nao YONEDA, Taiichi SHIKAMA, Hideki ZUSHI1), Kazuaki HANADA1), Akinobu FUJIKAWA, Takumi ONCHI1), Kengoh KURODA1), Kuniaki NII, Masahiro HASUO, Makoto HASEGAWA1), Hiroshi IDEI1), Kazuo NAKAMURA1), Yoshihiko NAGASHIMA1), Aki HIGASHIJIMA1) and Takahiro NAGATA1)
Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 615-8540, Japan
1)
Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580, Japan
(Received 28 December 2017 / Accepted 16 April 2018 / Published 10 July 2018)

Abstract

Toroidal electron cyclotron resonance (ECR) plasma is an ECR heated plasma in an open toroidal magnetic field. The plasma contains no toroidal current and is used for the pre-ionization and non-inductive startup of a tokamak plasma. To obtain a deeper understanding of the basic properties of the plasmas produced in the spherical tokamak QUEST (Q-shu University Experiment with steady-state Spherical Tokamak), we have developed an optical emission spectroscopy system with multiple viewing chords and have used it to measure the spatial distributions of the toroidal and poloidal flow velocities of C2+ ions. We compare the measured velocities with those calculated from the ion drift equations using the plasma parameters reported for a similar spherical tokamak, LATE (the Low Aspect Ratio Torus Experiment).

Keywords

emission spectroscopy, flow measurement, non-inductive startup, electron cyclotron resonance (ECR) heated plasma, spatial distribution

DOI: 10.1585/pfr.13.3402087

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