Material erosion and deposition on the divertor of W7-X

M. Mayer, M. Balden, S. Brezinsek, V. V. Burwitz, C. P. Dhard, A. Dudek, G. Ehrke, Y. Gao, H. Greuner, R. Guimarães, P. Hiret, S. Klose, R. König, M. Krause, R. Laube, M. Laux, D. Naujoks, R. Neu, J. Oelmann, C. RusetT. S. Silva, R. Yi, D. Zhao

Research output: Contribution to journalConference articlepeer-review

19 Scopus citations

Abstract

The net erosion and deposition pattern of carbon from the Test Divertor Unit (TDU) of the stellarator W7-X was determined. Special target elements with marker layers consisting of about 300 nm molybdenum and 5-10 μm carbon on top were used during the operational phase OP 1.2a. The thicknesses of the marker layers were determined by elastic backscattering spectrometry (EBS) using 2.5 MeV protons before and after plasma exposure and laser-induced breakdown spectroscopy on selected target elements after exposure. Scanning electron microscopy was used for investigating the surface morphology before and after exposure. Massive erosion of up to 20 μm carbon was observed at the strike line, in total 48 ± 14 g carbon were eroded from the 10 TDUs. The erosion was laterally non-uniform on the micro-scale. Strongly eroded surfaces were considerably smoother as compared to the original material. Only very little deposition of carbon is observed on the TDU: This means that the TDU is a large net erosion source.

Original languageEnglish
Article number014035
JournalPhysica Scripta
Volume2020
Issue numberT171
DOIs
StatePublished - 1 Jan 2020
Externally publishedYes
Event17th International Conference on Plasma-Facing Materials and Components for Fusion Applications, PFMC 2019 - Eindhoven, Netherlands
Duration: 20 May 201924 May 2019

Keywords

  • Carbon
  • Elastic backscattering (ebs)
  • Erosion/deposition
  • Laser-induced breakdown spectroscopy (libs)
  • Test divertor unit (tdu)
  • W7-x

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