HL-2A托卡马克上blob结构的喷气成像观测和定量研究  

Observation and quantitative study of blob structures using a gas puff imaging diagnostic on the HL-2A tokamak

作　　者：袁金榜 袁博达 许敏[1] 余羿 聂林[1] HL-2A实验团队 YUAN Jin-bang;YUAN Bo-da;XU Min;YU Yi;NIE Lin;HL-2A Experimental Team(Southwestern Institute of Physics,Chengdu 610041;Sun Yat-sen University,Zhuhai 519082)

机构地区：[1]核工业西南物理研究院,成都610041 [2]中山大学,珠海519082

出　　处：《核聚变与等离子体物理》2024年第4期464-469,共6页Nuclear Fusion and Plasma Physics

基　　金：国家磁约束核聚变能发展研究专项(2022YFE03100002,2019YFE03060002);国家自然科学基金(U1867222,U1967206,51821005)。

摘　　要：在HL-2A装置上发展了一套用于边界和刮削层(SOL)中等离子体涨落测量的喷气成像(GPI)诊断系统,该诊断测量范围在弱场侧中平面附近,测量范围大小为160mm×160mm,极向-径向的空间分辨能力为2.5mm×2.5mm,时间分辨能力为3~10μs。通过与朗缪尔探针数据的对比,验证了GPI诊断可以得到高时空分辨率的等离子体密度扰动数据。本研究发展了分析GPI实验数据的椭圆拟合算法,从而定量研究大尺度相干结构(blob)的结构与运动。在此基础上,分别计算得到了blob位置、空间尺度(包括极向、径向特征长度)及运动速度等关键参数。blob空间尺度的演化验证了极向剪切流对大尺度湍流结构的拉伸及剪切分裂作用,且观察到极向运动由边界径向电场驱动的E_(r)×B极向流主导。而blob径向速度向外,符合blob内部极向方向的电荷分离驱动了blob径向运动的分析。结果验证了椭圆拟合算法在GPI数据分析中的重要应用,为将来研究blob的演化过程提供了重要的测量分析方法和实验基础。On the HL-2A tokamak,a gas puff imaging(GPI)diagnostic system was developed for the measurement of plasma fluctuations in edge and scrap-off layer(SOL).This diagnostic covers a 160mm×160mm plane near the mid-plane.The poloidal-radial spatial resolution was 2.5mm×2.5mm and temporal resolution is 3~10μs.The GPI line intensity data are compared with ion saturation current data by Langmuir probe,and the results verify that GPI diagnostic can measure plasma density perturbations with high spatial and temporal resolution.In this paper,an elliptic fitting algorithm is developed to analyze the experimental data collected by GPI to quantitatively study the structure and motion of blobs.On this basis,key parameters such as blob location,spatial scale(including poloidal and radial scale length)and motion velocity are calculated,respectively.The titling and splitting effects of poloidal shear flow on blobs are observed,and it is observed that the blob’s poloidal motions are dominated by E_(r)×B flow.The radial velocity of blob is toward the first wall,consistent with the analysis.These results verify the successful application of elliptic fitting algorithm in GPI data analysis,and provide an important method and experimental basis for the future study of blob evolution.

关 键 词：喷气成像诊断系统 大尺度相干结构blob 椭圆拟合 

分 类 号：O536[理学—等离子体物理]