Experimental observations of bifurcated power decay lengths in the near Scrape-Off Layer of ST40 High Field Spherical Tokamak

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

Nuclear Materials and Energy Pub Date : 2024-10-22 DOI:10.1016/j.nme.2024.101772

X. Zhang , C. Marsden , M. Moscheni , E.N.J. Maartensson , A. Rengle , M. Robinson , T. O’Gorman , H.F. Lowe , E. Vekshina , S. Janhunen , A. Scarabosio , P.F. Buxton , M. Sertoli , M. Romanelli , S.A.M. McNamara , T.K. Gray , N.A. Lopez , the ST40 Team

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引用次数: 0

Abstract

The scrape-off layer parallel heat flux decay lengths measured at ST40, a high field, low aspect ratio spherical tokamak, have been observed to bifurcate into two groups. The wide group follows established H-mode scalings (ranging between 2 to 8 mm) while the narrow group falls up to 10 times below these scalings (between 0.2 and 0.8 mm), being comparable to the ion total Larmor radius rather than the ion poloidal Larmor radius. The heat flux profiles of the latter group can only be described by a multi-exponential function, rather than the single exponential function convoluted with a Gaussian. The onset of the narrow scrape-off layer width is observed to be associated with suppressed magnetic fluctuations, suggesting reduced electromagnetic turbulence levels in the SOL.

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对 ST40 高磁场球形托卡马克近刮除层分叉功率衰减长度的实验观测

在 ST40（一种高磁场、低长宽比的球形托卡马克）测量到的刮除层平行热通量衰减长度被观测到分为两组。宽的一组遵循既定的 H 模式标度（范围在 2 至 8 毫米之间），而窄的一组则比这些标度低 10 倍（在 0.2 至 0.8 毫米之间），与离子的总拉莫尔半径而不是离子的极拉莫尔半径相当。后一组的热通量曲线只能用多指数函数来描述，而不是用高斯卷积的单指数函数。据观测，窄刮除层宽度的出现与磁波动被抑制有关，这表明 SOL 中的电磁湍流水平降低了。

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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.