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核工业西南物理研究院 ›› 2024, Vol. 44 ›› Issue (4): 464-469.DOI: 10.16568/j.0254-6086.202404014

• 等离子体物理 • 上一篇    下一篇

HL-2A 托卡马克上 blob 结构的喷气成像观测和定量研究

袁金榜 1,袁博达 1,许 敏*1,余 羿 2,聂 林 1,HL-2A 实验团队 1   

  1. (1. 核工业西南物理研究院,成都 610041;2. 中山大学,珠海 519082)
  • 收稿日期:2023-03-24 修回日期:2023-12-18 出版日期:2024-12-15 发布日期:2024-12-12
  • 作者简介:袁金榜(1995-),男,河南开封人,硕士研究生,助理研究员,研究方向为等离子体边界湍流及诊断。
  • 基金资助:
    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)

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

YUAN Jin-bang1, YUAN Bo-da1, XU Min1, YU Yi2, NIE Lin1, HL-2A Experimental Team1   

  1. (1. Southwestern Institute of Physics, Chengdu 610041; 2. Sun Yat-sen University, Zhuhai 519082)
  • Received:2023-03-24 Revised:2023-12-18 Online:2024-12-15 Published:2024-12-12

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 Er×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。

关键词: 喷气成像诊断系统, 大尺度相干结构 blob, 椭圆拟合

Abstract: 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 Er×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.

Key words: Gas puff imaging diagnostic, Blob, Elliptic fitting

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