[Table of Contents]

Plasma and Fusion Research

Volume 9, 1402149 (2014)

Regular Articles

Ka-band Microwave Frequency Comb Doppler Reflectometer System for the Large Helical Device
Tokihiko TOKUZAWA, Shigeru INAGAKI1), Akira EJIRI2), Ryota SOGA3), Ichihiro YAMADA, Shin KUBO, Mikiro YOSHINUMA, Katsumi IDA, Chihiro SUZUKI, Kenji TANAKA, Tsuyoshi AKIYAMA, Naohiro KASUYA1), Kimitaka ITOH, Kiyomasa WATANABE, Hiroshi YAMADA, Kazuo KAWAHATA and LHD Experiment Group
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
1)
Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan
2)
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan
3)
Department of Energy Engineering and Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
(Received 9 July 2014 / Accepted 8 September 2014 / Published 26 December 2014)

Abstract

A ka-band multi-channel Doppler reflectometer system was constructed for the Large Helical Device (LHD) using a comb frequency generator as a source. A filter bank system is utilized for precise quadrature phase detection, and preliminary back-scattered waves were obtained in LHD plasma experiments. In addition, a direct digital signal acquisition system was successfully demonstrated for providing a greater number of multi-channel measurements.

Keywords

Doppler reflectometer, frequency comb, microwave, density fluctuation, poloidal velocity

DOI: 10.1585/pfr.9.1402149

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This paper may be cited as follows:

Tokihiko TOKUZAWA, Shigeru INAGAKI, Akira EJIRI, Ryota SOGA, Ichihiro YAMADA, Shin KUBO, Mikiro YOSHINUMA, Katsumi IDA, Chihiro SUZUKI, Kenji TANAKA, Tsuyoshi AKIYAMA, Naohiro KASUYA, Kimitaka ITOH, Kiyomasa WATANABE, Hiroshi YAMADA, Kazuo KAWAHATA and LHD Experiment Group, Plasma Fusion Res. 9, 1402149 (2014).