Smick Noah, LaBombard Brian
Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Rev Sci Instrum. 2009 Feb;80(2):023502. doi: 10.1063/1.3069290.
A new, high-field side scanning probe has been added to Alcator C-Mod's complement of edge diagnostics. The wall scanning probe is designed to provide all the benefits of a linear plunge, multielectrode scanning probe while working from the confined space of the inner tokamak wall. The drive mechanism is an embedded coil which produces a torque with the ambient toroidal magnetic field when energized, thus allowing the probe to plunge to different preprogramed depths at different times during a plasma discharge. The probe tip is designed for easy replacement and is presently configured to operate as a modified, high heat-flux "Gundestrup-type" probe with four tungsten electrodes. The probe has demonstrated the ability to obtain cross-field profiles for electron temperature, density, floating potential, and plasma flow information (parallel and perpendicular to B) up to a depth of a few millimiters inside the last-closed flux surface in standard C-Mod discharges. The tungsten-tipped probe has proved very robust and shows little or no damage though it routinely handles surface heat fluxes on the order of 100 MW/m(2) at peak insertion.
一个新的高场侧扫描探针已被添加到阿尔卡特C-Mod装置的边缘诊断设备中。壁扫描探针旨在从托卡马克内部壁的有限空间内工作时，提供线性插入式多电极扫描探针的所有优点。驱动机构是一个嵌入式线圈，通电时会与周围的环形磁场产生扭矩，从而使探针在等离子体放电期间的不同时间能够插入到不同的预编程深度。探针尖端设计易于更换，目前配置为作为一个带有四个钨电极的改进型高热流“贡德斯特鲁普型”探针运行。在标准C-Mod放电中，该探针已证明能够在最后闭合磁通面内几毫米的深度范围内获取电子温度、密度、浮动电位和等离子体流信息（平行和垂直于磁场B）的跨场分布。事实证明，这种钨尖探针非常坚固，尽管在峰值插入时它经常承受约100 MW/m²量级的表面热通量，但几乎没有损坏。
