Preparation of erosion and deposition investigations on plasma facing components in Wendelstein 7-X

C. P. Dhard, M. Balden, T. Braeuer, S. Brezinsek, J. W. Coenen, A. Dudek, G. Ehrke, D. Hathiramani, S. Klose, R. König, M. Laux, Ch Linsmeier, A. Manhard, S. Masuzaki, M. Mayer, G. Motojima, D. Naujoks, R. Neu, O. Neubauer, M. RackC. Ruset, T. Schwarz-Selinger, T. Sunn Pedersen, M. Tokitani, B. Unterberg, M. Yajima

Research output: Contribution to journalConference articlepeer-review

11 Scopus citations

Abstract

In the Wendelstein 7-X stellarator with its twisted magnetic geometry the investigation of plasma wall interaction processes in 3D plasma configurations is an important research subject. For the upcoming operation phase i.e. OP1.2, three different types of material probes have been installed within the plasma vessel for the erosion/deposition investigations in selected areas with largely different expected heat load levels, namely, ≤10 MW m-2 at the test divertor units (TDU), ≤500 kW m-2 at the baffles, heat shields and toroidal closures and ≤100 kW m-2 at the stainless steel wall panels. These include 18 exchangeable target elements at TDU, about 30 000 screw heads at graphite tiles and 44 wafer probes on wall panels, coated with marker layers. The layer thicknesses, surface morphologies and the impurity contents were pre-characterized by different techniques and subjected to various qualification tests. The positions of these probes were fixed based on the strike line locations on the divertor predicted by field line diffusion and EMC3/EIRENE modeling calculations for the OP1.2 plasma configurations and availability of locations on panels in direct view of the plasma. After the first half of the operation phase i.e. OP1.2a the probes will be removed to determine the erosion/deposition pattern by post-mortem analysis and replaced by a new set for the second half of the operation phase, OP1.2b.

Original languageEnglish
Article number014010
JournalPhysica Scripta
Volume2017
Issue numberT170
DOIs
StatePublished - 1 Dec 2017
Event16th International Conference on Plasma-Facing Materials and Components for Fusion Applications, PFMC 2017 - Neuss/Dusseldorf, Germany
Duration: 16 May 201719 May 2017

Keywords

  • Wendelstein 7-X
  • erosion and deposition
  • plasma facing components
  • plasma wall interaction

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