Gas puff imaging of plasma turbulence in the magnetic island scrape-off layer of W7-X

IF 2.3 2区物理与天体物理 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Nuclear Materials and Energy Pub Date : 2025-04-18 DOI:10.1016/j.nme.2025.101937

S.G. Baek , S. Ballinger , O. Grulke , C. Killer , A. von Stechow , J.L. Terry , F. Scharmer , B. Shanahan

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Abstract

The turbulence characteristics of the scrape-off-layer (SOL) plasma in the W7-X stellarator are investigated using a gas-puff-imaging (GPI) diagnostic, newly installed and operated during the OP 2.1 campaign. The SOL plasma on W7-X features a set of island divertors for heat and particle exhaust and provides a unique environment for studying SOL turbulence and transport. This paper focuses on the O-point region of the magnetic island divertor SOL in the standard magnetic configuration. Fourier and cross-correlation analyses show that turbulence flows are predominantly in the poloidal direction (i.e., direction tangent to the last closed flux surface) with significantly weaker radial motion. This suggests dominant ExB convection and suppressed filamentary transport compared to those observed in the far scrape-off-layer region of tokamaks, as further supported by high-resolution skewness and kurtosis data that show the absence of intermittent, bursty filamentary events. Additionally, a relationship between the radial profile of the connection length and the sheared poloidal flow structure is reported, suggesting a possible linkage among magnetic topology, turbulence dynamics, and turbulence generation.

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W7-X磁岛刮擦层等离子体湍流的气泡成像

使用在OP 2.1战役期间新安装并运行的气泡成像（GPI）诊断装置，研究了W7-X仿星器中刮擦层（SOL）等离子体的湍流特性。W7-X上的SOL等离子体具有一套用于热量和粒子排气的岛状分流器，为研究SOL湍流和输送提供了独特的环境。本文研究了标准磁结构下磁岛导流器SOL的o点区域。傅里叶和互相关分析表明，湍流流动主要在极向方向（即与最后一个封闭通量面相切的方向），径向运动明显减弱。这表明，与在托卡马克的远刮脱层区观测到的相比，ExB对流占主导地位，丝状运输受到抑制，高分辨率的偏度和峰度数据进一步支持了这一点，表明没有间歇性的，突发的丝状事件。此外，据报道，连接长度的径向轮廓与剪切极向流结构之间存在关系，表明磁性拓扑结构、湍流动力学和湍流产生之间可能存在联系。

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来源期刊

Nuclear Materials and Energy Materials Science-Materials Science (miscellaneous)

CiteScore

3.70

自引率

15.40%

发文量

175

审稿时长

20 weeks

期刊介绍： The open-access journal Nuclear Materials and Energy is devoted to the growing field of research for material application in the production of nuclear energy. Nuclear Materials and Energy publishes original research articles of up to 6 pages in length.