Experimental study of core MHD behavior and a novel algorithm for rational surface detection based on profile reflectometry in EAST  

作　　者：叶凯萱 周振 张涛 马九阳 王嵎民 李恭顺 耿康宁 吴茗甫 文斐 黄佳 张洋 邵林明 杨书琪 钟富彬 高善露 喻琳 周子强 向皓明 韩翔 张寿彪 李国强 高翔 the EAST Team Kaixuan YE;Zhen ZHOU;Tao ZHANG;Jiuyang MA;Yumin WANG;Gongshun LI;Kangning GENG;Mingfu WU;Fei WEN;Jia HUANG;Yang ZHANG;Linming SHAO;Shuqi YANG;Fubin ZHONG;Shanlu GAO;Lin YU;Ziqiang ZHOU;Haoming XIANG;Xiang HAN;Shoubiao ZHANG;Guoqiang LI;Xiang GAO;the EAST Team(Institute of Plasma Physics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,People's Republic of China;University of Science and Technology of China,Hefei 230026,People's Republic of China;Hebei Key Laboratory of Compact Fusion,Langfang 065001,Peoples Republic of China;ENN Science and Technology Development Co.,Ltd.,Langfang 065001,Peoples Republic of China;Advanced Energy Research Center,Shenzhen University,Shenzhen 518060,People's Republic of China)

机构地区：[1]Institute of Plasma Physics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,People's Republic of China [2]University of Science and Technology of China,Hefei 230026,People's Republic of China [3]Hebei Key Laboratory of Compact Fusion,Langfang 065001,Peoples Republic of China [4]ENN Science and Technology Development Co.,Ltd.,Langfang 065001,Peoples Republic of China [5]Advanced Energy Research Center,Shenzhen University,Shenzhen 518060,People's Republic of China

出　　处：《Plasma Science and Technology》2024年第3期66-75,共10页等离子体科学和技术（英文版）

基　　金：supported by the Open Fund of Magnetic Confinement Laboratory of Anhui Province(No.2023 AMF03005);the China Postdoctoral Science Foundation(No.2021M703256);the Director Funding of Hefei Institutes of Physical Science,Chinese Academy of Sciences(No.YZJJ2022QN16);the National Key R&D Program of China(Nos.2022YFE03050003,2019YFE03080200,2019Y FE03040002,and 2022YFE03070004);National Natural Science Foundation of China(Nos.12075284,12175277,12275315 and 12275311);the National Magnetic Confinement Fusion Science Program of China(No.2022YFE03040001);the Science Foundation of the Institute of Plasma Physics,Chinese Academy of Sciences(No.DSJJ-2021-08)。

摘　　要：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 understanding the influence of plasma perturbations on the reflect signal is important.The characteristics of the reflect signal from profile reflectometry,the time-of-flight(TOF)signal associated with the MHD instabilities,are investigated in EAST.Using a 1D full-wave simulation code by the Finite-DifferenceTime-Domain(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 under 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 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.

关 键 词：MHD instabilities profile reflectometry rational surface detection convolutional neural network(CNN) EAST tokamak 

分 类 号：TL631.24[核科学技术—核技术及应用]