The DIII-D small angle slot (SAS) divertor is designed for divertor physics studies with enhanced neutral confinement and special target geometries in a closed divertor. The closed nature of the SAS makes optical diagnostic measurements difficult, so a specially designed, multipurpose array of Langmuir probes has been implemented to study the plasma conditions in and around the slot. The probes are spaced to provide at least 2 mm resolution (shorter than the energy decay length) of the near scrape-off layer when mapped to the outer mid-plane. Due to space limitations at the bottom of the slot, a novel spring-loaded probe and tile design was developed to clamp several short rooftop probe tips and insulators to the cooled baseplate. Initial probe measurements revealed tile to tile edge shadowing, especially where magnetic field line surface angles were less than 1°. Additionally, it was found, using three Langmuir probes (at 90°, 180°, and 270°), that the strike point variation of ±5 mm radially around the torus was not well aligned with the circular slot geometry [Watkins et al., Nucl. Mater. Energy 18, 46 (2019)]. These issues were resolved by (1) designing tiles with all probes mounted near the tile center instead of near the edges and (2) aligning these new custom tiles to the measured strike point toroidal surface with a very accurate laser scanning alignment tool. Post-alignment Langmuir probe measurements and plasma behavior demonstrated close agreement at two separate toroidal locations that were 45° apart.

中文翻译：

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用于 DIII-D 中小角狭缝偏滤器的朗缪尔探针阵列

DIII-D小角度狭槽（SAS）偏滤器设计用于具有封闭式偏滤器的增强的中性限制和特殊目标几何形状的偏滤器物理研究。SAS 的封闭特性使光学诊断测量变得困难，因此采用了专门设计的多用途朗缪尔探针阵列来研究槽内和槽周围的等离子体条件。当映射到外中平面时，探针间隔开以提供至少 2 毫米分辨率（比能量衰减长度更短）的近刮除层。由于槽底部的空间限制，开发了一种新颖的弹簧加载探头和瓷砖设计，以将几个短的屋顶探头尖端和绝缘体夹在冷却基板上。最初的探针测量显示瓷砖到瓷砖边缘阴影，特别是在磁力线表面角度小于 1° 的情况下。此外，发现使用三个朗缪尔探针（90°、180° 和 270°），围绕环面的 ±5 mm 径向撞击点变化与圆形槽几何结构 [Watkins等。，核。母校。能源18 , 46 (2019)]。这些问题的解决方法如下：(1) 将所有探头安装在瓷砖中心附近而不是边缘附近，以及 (2) 使用非常精确的激光扫描对准工具将这些新的定制瓷砖与测量的撞击点环形表面对准。对准后 Langmuir 探针测量和等离子体行为在两个相距 45° 的独立环形位置显示出非常一致的结果。