Development of O-Mode Polarized V-Band Multichannel Poloidal Correlation Reflectometry on EAST Tokamak

• Published in: IEEE transactions on plasma science Vol. 52; no. 2; pp. 423 - 430
• Main Authors: Li, Gongshun, Zhang, Tao, Geng, Kangning, Wen, Fei, Zhou, Zhen, Zhou, Ziqiang, Yu, Lin, Zhong, Fubin, Ye, Kaixuan, Yang, Shuqi, Ma, Jiuyang, Zhang, Shoubiao, Li, Guoqiang, Gao, Xiang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-02-2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas; Correlation; Cutoff frequency; Density; Fluctuations; Frequency division multiplexing; High density; Microwave filters; Microwave measurement; Microwave radiation; Microwave reflectometry; Microwaves; Nucleotide sequence; plasma measurements; Plasmas; Plasmas (physics); Probes; Receiving antennas; Reflected waves; Reflectometry; Tokamak devices; tokamaks
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/TPS.2024.3354257

A new O-mode polarized <inline-formula> <tex-math notation="LaTeX">V </tex-math></inline-formula>-band poloidal correlation reflectometry (PCR) has been designed and installed on the experimental advanced superconducting tokamak (EAST) to measure the core density fluctuation in high-density plasmas, especially in internal transport barrier (ITB) discharges. Four probing frequencies (61.2, 65.6, 69.2, and 73.6 GHz) are launched into the plasma simultaneously with an inclined view to ensure the probe waves are perpendicular to the cutoff layer. The reflected waves are received by two adjacent antennas, and this setup enables the system to measure the density fluctuations at eight spatial positions (4 radial <inline-formula> <tex-math notation="LaTeX">\times2 </tex-math></inline-formula> poloidal). The result of the bench test shows that all the key components perform well and meet the system requirements. The launching power of these probe microwaves coupled together is 18.22 dBm, the phase unbalance is lower than 5°, and the amplitude unbalance is below 1 dB. The system was successfully installed in the EAST, and the preliminary result is presented herein to examine the system's performance. The evolution of core density fluctuations during the density oscillations was observed, which indicated that the system could work well in high-density plasmas.