Microwave frequency comb Doppler reflectometer applying fast digital data acquisition system in LHD

T Tokuzawa; H Tsuchiya; T Tsujimura; M Emoto; H Nakanishi; S Inagaki; K Ida; H Yamada; A Ejiri; K Y Watanabe; K Oguri; T Akiyama; K Tanaka; I Yamada; LHD Experiment Group

doi:10.1063/1.5035118

Microwave frequency comb Doppler reflectometer applying fast digital data acquisition system in LHD

Rev Sci Instrum. 2018 Oct;89(10):10H118. doi: 10.1063/1.5035118.

Authors

T Tokuzawa¹, H Tsuchiya¹, T Tsujimura¹, M Emoto¹, H Nakanishi¹, S Inagaki², K Ida¹, H Yamada¹, A Ejiri³, K Y Watanabe¹, K Oguri⁴, T Akiyama¹, K Tanaka¹, I Yamada¹; LHD Experiment Group¹

Affiliations

¹ National Institutes of Natural Sciences, National Institute for Fusion Science, Toki 509-5292, Japan.
² Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan.
³ Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan.
⁴ Department of Energy Engineering and Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.

PMID: 30399698
DOI: 10.1063/1.5035118

Abstract

We succeeded in increasing the radial observation points of the microwave frequency comb Doppler reflectometer system from 8 to 20 (or especially up to 45) using the high sampling rate of 40 GS/s digital signal processing. For a new acquisition system, the estimation scheme of the Doppler shifted frequency is constructed and compared with the conventional technique. Also, the fine radial profile of perpendicular velocity is obtained, and it is found that the perpendicular velocity profile is consistent with the E × B drift velocity one.