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Title: Analysis of a tungsten sputtering experiment in DIII-D and code/data validation of high redeposition/reduced erosion

We analyze a DIII-D tokamak experiment where two tungsten spots on the removable DiMES divertor probe were exposed to 12 s of attached plasma conditions, with moderate strike point temperature and density (~20 eV, ~4.5 × 10 19 m –3), and 3% carbon impurity content. Both very small (1 mm diameter) and small (1 cm diameter) deposited samples were used for assessing gross and net tungsten sputtering erosion. The analysis uses a 3-D erosion/redeposition code package (REDEP/WBC), with input from a diagnostic-calibrated near-surface plasma code (OEDGE), and with focus on charge state resolved impinging carbon ion flux and energy. The tungsten surfaces are primarily sputtered by the carbon, in charge states +1 to +4. We predict high redeposition (~75%) of sputtered tungsten on the 1 cm spot—with consequent reduced net erosion—and this agrees well with post-exposure DiMES probe RBS analysis data. As a result, this study and recent related work is encouraging for erosion lifetime and non-contamination performance of tokamak reactor high-Z plasma facing components.
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [3]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. Purdue Univ., West Lafayette, IN (United States)
  3. Univ. of Toronto Institute for Aerospace Studies, Toronto (Canada)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  5. Univ. of California, San Diego, CA (United States)
Publication Date:
Report Number(s):
SAND-2014-20047J; LLNL-JRNL-698174
Journal ID: ISSN 0920-3796; 547393; TRN: US1600628
Grant/Contract Number:
AC04-94AL85000; AC52-07NA27344; FC02-04ER54698; FG02-07ER54917
Accepted Manuscript
Journal Name:
Fusion Engineering and Design
Additional Journal Information:
Journal Volume: 94; Journal Issue: C; Journal ID: ISSN 0920-3796
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); General Atomics, San Diego, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-4); USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; sputtering; erosion/redeposition; tungsten divertor; plasma material interaction modeling; 70 PLASMA PHYSICS AND FUSION
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1305822; OSTI ID: 1376234