Hannover 2020 – scientific programme
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P: Fachverband Plasmaphysik
P 5: Poster Session 1
P 5.4: Poster
Monday, March 9, 2020, 16:30–18:30, Empore Lichthof
Pedestal turbulence studies with means of O-mode correlation reflectometry on EAST — •Haoming Xiang1,2, Tao Zhang2, Xiang Gao2, Fei Wen2, Yumin Wang2, Xiang Han1,2, Jianbin Liu2, Andreas Krämer-Flecken1, and Yunfeng Liang1 — 1Institut für Energie- und Klimaforschung, Forschungszentrum Jülich, 52425 Jülich — 2Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei, Anhui 230031, People’s Republic of China
A multi-frequency ordinary-mode correlation reflectometer has been developed and operated on EAST to measure plasma electron density fluctuations. Simultaneous four-frequency operation makes it possible to measure the correlation between fluctuations at different radially separated cut-off layers. Furthermore, two poloidally spaced receiving antennas allows to investigate the correlation between fluctuations at different poloidal positions and thus determine of turbulence velocity. During the EAST experimental campaign in 2018, a low-frequency coherent mode(f≈ 1kHz) in the pedestal region during the ELM-free phase is investigated. Magnetic probes measurements show that the low frequency mode exhibits a structure of toroidal number (n=0) and poloidal number (m=1). Correlation reflectometer analysis show that there is no phase difference radially, i.e., not a radial traveling wave. Further study shows that pedestal density fluctuation and thus the pedestal density/density gradient are modulated by this low-frequency mode,the measurements will be discussed in this presentation.