Plasma and Fusion Research

Volume 11, 2402123 (2016)

Regular Articles

Development of 2D Potential Profile Measurements Using the Heavy Ion Beam Probe on the Large Helical Device
Akihiro SHIMIZU1), Takeshi IDO1,2), Masaki NISHIURA3), Hiromi TAKAHASHI1), Hiroe IGAMI1), Yasuo YOSHIMURA1), Shin KUBO1,2), Takashi SHIMOZUMA1), Shinji KATO1), Masayuki YOKOYAMA1,4) and LHD Experiment Group1)
1)
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
2)
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-0814, Japan
3)
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan
4)
The Graduate University for Advanced Studies (Sokendai), 322-6 Oroshi-cho, Toki 509-5292, Japan
(Received 30 November 2015 / Accepted 13 July 2016 / Published 9 December 2016)

Abstract

Two-dimensional potential fluctuation profiles were measured with the heavy ion beam probe (HIBP) on the Large Helical Device. For two-dimensional measurements with HIBP, the probe beam energy had to be changed, and subtle adjustment of the beam trajectory along the long beam transport line (∼20 m) was required. An automatic beam adjustment system was developed for the beam transport line, and used to easily adjust the probe beam trajectory. Potential fluctuations in the high-frequency range (∼200 kHz) were measured, and the probe beam energy was changed shot to shot. Two-dimensional potential phase structures were successfully obtained by analyzing the coherence between potential and magnetic field fluctuation, which is used as a reference signal.

Keywords

heavy ion beam probe (HIBP), two-dimensional potential profile, helical device, the Large Helical Device (LHD)

DOI: 10.1585/pfr.11.2402123

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