Deposition in the inner and outer corners of the JET divertor with carbon wall and metallic ITER-like wall

J. Beal, A. Widdowson, K. Heinola, A. Baron-Wiechec, K. J. Gibson, J. P. Coad, E. Alves, B. Lipschultz, A. Kirschner, H. G. Esser, G. F. Matthews, S. Brezinsek

Research output: Contribution to journalConference articlepeer-review

11 Scopus citations

Abstract

Rotating collectors and quartz microbalances (QMBs) are used in JET to provide time-dependent measurements of erosion and deposition. Rotation of collector discs behind apertures allows recording of the long term evolution of deposition. QMBs measure mass change via the frequency deviations of vibrating quartz crystals. These diagnostics are used to investigate erosion/deposition during JET-C carbon operation and JET-ILW (ITER-like wall) beryllium/tungsten operation. A simple geometrical model utilising experimental data is used to model the time-dependent collector deposition profiles, demonstrating good qualitative agreement with experimental results. Overall, the JET-ILW collector deposition is reduced by an order of magnitude relative to JET-C, with beryllium replacing carbon as the dominant deposit. However, contrary to JET-C, in JET-ILW there is more deposition on the outer collector than the inner. This reversal of deposition asymmetry is investigated using an analysis of QMB data and is attributed to the different chemical properties of carbon and beryllium.

Original languageEnglish
Article number014052
JournalPhysica Scripta
Volume2016
Issue numberT167
DOIs
StatePublished - 25 Jan 2016
Externally publishedYes
Event15th International Conference on Plasma-Facing Materials and Components for Fusion Applications, PFMC 2015 - Aix-en-Provence, France
Duration: 18 May 201522 May 2015

Keywords

  • JET
  • deposition
  • erosion
  • tokamak

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