%0 Journal Article
%A Ding, R.
%A Rudakov, D. L.
%A Stangeby, P. C.
%A Wampler, W. R.
%A Abrams, T.
%A Brezinsek, S.
%A Briesemeister, A.
%A Bykov, I.
%A Chan, V. S.
%A Chrobak, C. P.
%A Elder, J. D.
%A Guo, H. Y.
%A Guterl, J.
%A Kirschner, A.
%A Lasnier, C. J.
%A Leonard, A. W.
%A Makowski, M. A.
%A McLean, A. G.
%A Snyder, P. B.
%A Thomas, D. M.
%A Tskhakaya, D.
%A Unterberg, E. A.
%A Wang, H. Q.
%A Watkins, J. G.
%T Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D
%J Nuclear fusion
%V 57
%N 5
%@ 1741-4326
%C Vienna
%I IAEA
%M FZJ-2017-05108
%P 056016 -
%D 2017
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000399125300003
%R 10.1088/1741-4326/aa6451
%U https://juser.fz-juelich.de/record/835983