Kaixuan Ye, Zhen Zhou, Tao Zhang, Jiuyang Ma, Yumin Wang, Gongshun Li, K. Geng, Ming-Shan Wu, Fei Wen, Jia Huang, Yang Zhang, Lin Ming Shao, Shuqi Yang, Fubin Zhong, S. Gao, Lin Yu, Ziqiang Zhou, Haoming Xiang, Xiang Han, Shoubiao Zhang, Guoqiang Li, Xiang Gao
{"title":"Experimental study of core MHD behavior and novel algorithm of rational surface detection based on profile reflectometry in EAST","authors":"Kaixuan Ye, Zhen Zhou, Tao Zhang, Jiuyang Ma, Yumin Wang, Gongshun Li, K. Geng, Ming-Shan Wu, Fei Wen, Jia Huang, Yang Zhang, Lin Ming Shao, Shuqi Yang, Fubin Zhong, S. Gao, Lin Yu, Ziqiang Zhou, Haoming Xiang, Xiang Han, Shoubiao Zhang, Guoqiang Li, Xiang Gao","doi":"10.1088/2058-6272/ad0f0a","DOIUrl":null,"url":null,"abstract":"Microwave reflectometry is a powerful diagnostic that can measure the density profile and localized turbulence with high spatial and temporal resolution and will be used in ITER, so the understanding of the influence of plasma perturbations on the reflect signal is important. The characteristics of the reflect signal from profile reflectometry, the time-of-fight (TOF) signal to the MHD instabilities are investigated in EAST. Using a 1D full-wave simulation code by the FDTD method, it is well validated that the local density flattening could induce the discontinuity of the simulated TOF signal and an obvious change of reflect amplitude. Experimental TOF signals associated with different types of MHD instabilities (sawtooth, sawtooth precursors and tearing mode) are studied in detail and show agreement with the simulation. Two new improved algorithms for detecting and localizing the radial positions of the low-order rational surface, the Cross-correlation and Gradient Threshold (CGT) method and the 2D Convolutional Neural Network approach (CNN) are presented for the first time. It is concluded that the TOF signal analysis from profile reflectometry can provide a straightforward and localized measurement of the plasma perturbation from the edge to the core simultaneously and may be a complement or correction to the q-profile control, which will be beneficial for the advanced tokamak operation.","PeriodicalId":20250,"journal":{"name":"Plasma Science & Technology","volume":null,"pages":null},"PeriodicalIF":1.6000,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Plasma Science & Technology","FirstCategoryId":"1089","ListUrlMain":"https://doi.org/10.1088/2058-6272/ad0f0a","RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, FLUIDS & PLASMAS","Score":null,"Total":0}
引用次数: 0
Abstract
Microwave reflectometry is a powerful diagnostic that can measure the density profile and localized turbulence with high spatial and temporal resolution and will be used in ITER, so the understanding of the influence of plasma perturbations on the reflect signal is important. The characteristics of the reflect signal from profile reflectometry, the time-of-fight (TOF) signal to the MHD instabilities are investigated in EAST. Using a 1D full-wave simulation code by the FDTD method, it is well validated that the local density flattening could induce the discontinuity of the simulated TOF signal and an obvious change of reflect amplitude. Experimental TOF signals associated with different types of MHD instabilities (sawtooth, sawtooth precursors and tearing mode) are studied in detail and show agreement with the simulation. Two new improved algorithms for detecting and localizing the radial positions of the low-order rational surface, the Cross-correlation and Gradient Threshold (CGT) method and the 2D Convolutional Neural Network approach (CNN) are presented for the first time. It is concluded that the TOF signal analysis from profile reflectometry can provide a straightforward and localized measurement of the plasma perturbation from the edge to the core simultaneously and may be a complement or correction to the q-profile control, which will be beneficial for the advanced tokamak operation.
期刊介绍:
PST assists in advancing plasma science and technology by reporting important, novel, helpful and thought-provoking progress in this strongly multidisciplinary and interdisciplinary field, in a timely manner.
A Publication of the Institute of Plasma Physics, Chinese Academy of Sciences and the Chinese Society of Theoretical and Applied Mechanics.