Journal Article

FZJ-2017-05108

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D

Ding, R. (Corresponding author) ; Rudakov, D. L. ; Stangeby, P. C. ; Wampler, W. R. ; Abrams, T. ; Brezinsek, S. (Corresponding author)FZJ* ; Briesemeister, A. ; Bykov, I. ; Chan, V. S. ; Chrobak, C. P. ; Elder, J. D. ; Guo, H. Y. ; Guterl, J. ; Kirschner, A.FZJ* ; Lasnier, C. J. ; Leonard, A. W. ; Makowski, M. A. ; McLean, A. G. ; Snyder, P. B. ; Thomas, D. M. ; Tskhakaya, D. ; Unterberg, E. A. ; Wang, H. Q. ; Watkins, J. G.

2017
IAEA Vienna

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Please use a persistent id in citations: doi:10.1088/1741-4326/aa6451

Abstract: Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high-Z materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. Different methods such as electrical biasing and local gas injection have been investigated to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed by reducing the sheath potential drop. A high carbon impurity concentration in the background plasma is also found to reduce the net erosion rate of high-Z materials. Both DIII-D experiments and modeling show that local 13CH4 injection can create a carbon coating on the metal surface. The profile of 13C deposition provides quantitative information on radial transport due to E  ×  B drift and the cross-field diffusion. The deuterium gas injection upstream of the W sample can reduce W net erosion rate by plasma perturbation. In H-mode plasmas, the measured inter-ELM W erosion rates at different radial locations are well reproduced by ERO modeling taking into account charge-state-resolved carbon ion flux in the background plasma calculated using the OEDGE code.

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Contributing Institute(s):

1. Plasmaphysik (IEK-4)

Research Program(s):

1. 174 - Plasma-Wall-Interaction (POF3-174) (POF3-174)

Appears in the scientific report 2017

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Database coverage:
Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; National-Konsortium ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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