The effect of gyration on the deposition of beryllium and deuterium at rough surface on the divertor tiles with ITER-like-wall in JET

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Experimental results from microbeam analyses on divertor tiles, through 2011-2012 and 2013-2014 operations in JET-ILW, showed that the deuterium retention and beryllium impurity deposition were non-uniform on the rough surface in micro meter scale. Frequently, Be and D were accumulated within pits, cracks and valleys in the range of ∼10 μm to ∼100 μm and selectively at side slopes within larger pits. In the deposited layers, it was also observed that cylindrical structures grow in a specific direction with respect to the magnetic field. In this work, a sample from the divertor in JET-ILW following 2013-2014 operation was analysed. The surface topography was measured with the focus stacking technique on photos from optical microscope and elemental distribution maps were obtained by micro-ion-beam analysis. In order to figure out the effect of ion gyro motion on Be and D deposition on the real divertor topography, a modelling of ion trajectories in plasma boundary was performed. Ion beam analysis data suggested that D accumulated on higher areas on the sample, while Be stayed on lower positions. The gyration of ions in edge plasma and corresponding impact positions on the sample surface could explain some IBA results qualitatively.

Original languageEnglish
Pages (from-to)155-160
Number of pages6
JournalNuclear Materials and Energy
Volume19
DOIs
Publication statusE-pub ahead of print - Mar 2019
MoE publication typeNot Eligible

Fingerprint

Beryllium
Deuterium
tiles
gyration
Tile
beryllium
deuterium
Ions
Ion beams
topography
ion beams
Plasmas
ions
microbeams
Surface topography
optical microscopes
Topography
valleys
Microscopes
cracks

Keywords

  • Deuterium deposition
  • Divertor
  • JET
  • Micro-ion-beam

Cite this

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title = "The effect of gyration on the deposition of beryllium and deuterium at rough surface on the divertor tiles with ITER-like-wall in JET",
abstract = "Experimental results from microbeam analyses on divertor tiles, through 2011-2012 and 2013-2014 operations in JET-ILW, showed that the deuterium retention and beryllium impurity deposition were non-uniform on the rough surface in micro meter scale. Frequently, Be and D were accumulated within pits, cracks and valleys in the range of ∼10 μm to ∼100 μm and selectively at side slopes within larger pits. In the deposited layers, it was also observed that cylindrical structures grow in a specific direction with respect to the magnetic field. In this work, a sample from the divertor in JET-ILW following 2013-2014 operation was analysed. The surface topography was measured with the focus stacking technique on photos from optical microscope and elemental distribution maps were obtained by micro-ion-beam analysis. In order to figure out the effect of ion gyro motion on Be and D deposition on the real divertor topography, a modelling of ion trajectories in plasma boundary was performed. Ion beam analysis data suggested that D accumulated on higher areas on the sample, while Be stayed on lower positions. The gyration of ions in edge plasma and corresponding impact positions on the sample surface could explain some IBA results qualitatively.",
keywords = "Deuterium deposition, Divertor, JET, Micro-ion-beam",
author = "Y. Zhou and Henric Bergs{\aa}ker and P. Petersson and G{\"o}ran Possnert and J. Likonen",
year = "2019",
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pages = "155--160",
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The effect of gyration on the deposition of beryllium and deuterium at rough surface on the divertor tiles with ITER-like-wall in JET. / Culham Science Centre.

In: Nuclear Materials and Energy, Vol. 19, 03.2019, p. 155-160.

Research output: Contribution to journalArticleScientificpeer-review

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AU - Possnert, Göran

AU - Likonen, J.

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