Optics Design for Microwave Imaging Reflectometry in LHD

Tomokazu YOSHINAGA; Yoshio NAGAYAMA; Daisuke KUWAHARA; Hayato TSUCHIYA; Soichiro YAMAGUCHI; Yuichiro KOGI; Shunji TSUJI-IIO; Hitoshi HOJO; Atsushi MASE

doi:10.1585/pfr.5.030

Rapid Communications

Optics Design for Microwave Imaging Reflectometry in LHD

Tomokazu YOSHINAGA, Yoshio NAGAYAMA, Daisuke KUWAHARA, Hayato TSUCHIYA, Soichiro YAMAGUCHI, Yuichiro KOGI, Shunji TSUJI-IIO, Hitoshi HOJO, Atsushi MASE

Author information

Tomokazu YOSHINAGA
National Institute for Fusion Science, 322-6 Oroshi, Toki 509-5292, Japan
Yoshio NAGAYAMA
National Institute for Fusion Science, 322-6 Oroshi, Toki 509-5292, Japan
Daisuke KUWAHARA
Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8550, Japan
Hayato TSUCHIYA
National Institute for Fusion Science, 322-6 Oroshi, Toki 509-5292, Japan
Soichiro YAMAGUCHI
Kansai University, 3-3-35 Yamate, Suita 564-8680, Japan
Yuichiro KOGI
Fukuoka Institute of Technology, 3-30-1 Wajiro-Higashi, Fukuoka 811-0295, Japan
Shunji TSUJI-IIO
Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8550, Japan
Hitoshi HOJO
University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan
Atsushi MASE
Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8680, Japan

Keywords: microwave imaging reflectometry, quasi-optics design, finite-difference time-domain method

JOURNAL FREE ACCESS

2010 Volume 5 Pages 030

DOI https://doi.org/10.1585/pfr.5.030

Details

Abstract

An optics system for microwave imaging reflectometry (MIR) in the Large Helical Device (LHD) was newly developed to optimize the performance of the two-dimensional microwave receiver array. Reflected microwaves from the plasma and the first local oscillator (LO) wave are transmitted to the receiver array via the optics from the front. Finite-difference time-domain (FDTD) calculation was used to design the ellipsoidal or hyperboloidal shapes of the quasi-optical mirrors. It is confirmed that the LO beam in the constructed system covers the receiver antenna aperture area as intended. The S/N ratios of the signals are improved with this optimized optics system from those in the previous system.

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