Upgrades of the W-band Doppler reflectometry for the core region plasma measurement on EAST

作者：Lifu Gao, Feng Xi, A. D. Liu, Chu Zhou, W. X. Ding, Z. Y. Liu, G. Zhuang, Jinlin Xie, X. Zhong, Haiqing Liu, Shouxin Wang, Bin Zhang, Y. Zhang, Jin Zhang, Shifan Wang, Wenxiang Shi, Sichun Qiu, Liuxin Li, Xiaoying Chen, Yanyi Zhang, Hong Li, Tao Lan, Wenzhe Mao, Zixi Liu, Wandong Liu, the EAST team · 发表于：Plasma Physics and Controlled Fusion · 年份：2025 · DOI：10.1088/1361-6587/add599 · 被引用次数：2 · 研究领域：Magnetic confinement fusion research

Abstract The five-channel tunable W-band Doppler reflectometry installed in the Experimental Advanced Superconducting Tokamak (Feng et al 2019 Rev. Sci. Instrum. 90 024704) has been upgraded. The signal launching and receiving circuits have been separated in order to circumvent the reflection of the W-band filter on the launching microwave, thereby reducing the background noise in a wide frequency band. The frequency interval between adjacent channels has been increased from 400 MHz to 1 GHz to broaden the diagnostic range in the core. Following upgrades and the careful optimization of the power distribution between different channels, the performance in the high frequency range has been significantly enhanced. Current available bandwidth is 75 ∼ 100.4 GHz , and the region within ρ ∼ 0.2 can be covered in low density discharges ( n e < 2 × 10 19 m − 3 ) with a toroidal field B t = 2.5 T , which meets the fundamental requirements for measuring the plasma in the core region. During the internal transport barrier experiments investigating the fishbone instability, turbulence suppression could be distinctly identified, and the Doppler shift fluctuations related to the fishbone instability have been observed. The fluctuation amplitude calculated by the center of gravity method reaches 1 MHz , which is con...