Reciprocating probe measurements in the test divertor operation phase of Wendelstein 7-X

TL;DR

This paper reviews the use of reciprocating probes in Wendelstein 7-X's test divertor phase, highlighting probe designs, operational lessons, and notable measurement observations in complex magnetic geometries.

Contribution

It provides the first comprehensive overview of reciprocating probe operation and design considerations in the W7-X stellarator during its initial test divertor phase.

Findings

Diverse probe head designs were employed.

Operational challenges in complex magnetic fields were identified.

Unexpected measurement phenomena were observed.

Abstract

Reciprocating probes are a classic and widespread tool for the investigation of the edge and Scrape-Off Layer of magnetic fusion plasmas. In the Wendelstein 7-X (W7-X) stellarator, the Multi-Purpose Manipulator serves as a multi-user platform for probe measurements of various kinds. This paper presents a review on reciprocating probe operation during the first operation phase of W7-X with a test divertor (2017-2018). It gives an overview of the diverse zoo of probe heads and presents lessons learned about probe operation in complex magnetic geometries, operation safety, and probe head design. A few examples of probe measurements with a focus on unexpected observations are presented.