TY  - JOUR
AU  - Ding, R.
AU  - Rudakov, D. L.
AU  - Stangeby, P. C.
AU  - Wampler, W. R.
AU  - Abrams, T.
AU  - Brezinsek, S.
AU  - Briesemeister, A.
AU  - Bykov, I.
AU  - Chan, V. S.
AU  - Chrobak, C. P.
AU  - Elder, J. D.
AU  - Guo, H. Y.
AU  - Guterl, J.
AU  - Kirschner, A.
AU  - Lasnier, C. J.
AU  - Leonard, A. W.
AU  - Makowski, M. A.
AU  - McLean, A. G.
AU  - Snyder, P. B.
AU  - Thomas, D. M.
AU  - Tskhakaya, D.
AU  - Unterberg, E. A.
AU  - Wang, H. Q.
AU  - Watkins, J. G.
TI  - Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D
JO  - Nuclear fusion
VL  - 57
IS  - 5
SN  - 1741-4326
CY  - Vienna
PB  - IAEA
M1  - FZJ-2017-05108
SP  - 056016 -
PY  - 2017
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000399125300003
DO  - DOI:10.1088/1741-4326/aa6451
UR  - https://juser.fz-juelich.de/record/835983
ER  -