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This content will become publicly available on December 17, 2016

Title: Simulation of gross and net erosion of high-Z materials in the DIII-D divertor

The three-dimensional Monte Carlo code ERO has been used to simulate dedicated DIII-D experiments in which Mo and W samples with different sizes were exposed to controlled and well-diagnosed divertor plasma conditions to measure the gross and net erosion rates. Experimentally, the net erosion rate is significantly reduced due to the high local redeposition probability of eroded high-Z materials, which according to the modelling is mainly controlled by the electric field and plasma density within the Chodura sheath. Similar redeposition ratios were obtained from ERO modelling with three different sheath models for small angles between the magnetic field and the material surface, mainly because of their similar mean ionization lengths. The modelled redeposition ratios are close to the measured value. Decreasing the potential drop across the sheath can suppress both gross and net erosion because sputtering yield is decreased due to lower incident energy while the redeposition ratio is not reduced owing to the higher electron density in the Chodura sheath. Taking into account material mixing in the ERO surface model, the net erosion rate of high-Z materials is shown to be strongly dependent on the carbon impurity concentration in the background plasma; higher carbon concentration can suppress net erosion.more » As a result, the principal experimental results such as net erosion rate and profile and redeposition ratio are well reproduced by the ERO simulations.« less
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [7] ;  [9]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. General Atomics, San Diego, CA (United States); Chinese Academy of Sciences (CAS), Anhui (People's Republic of China); Oak Ridge Associated Univ., Oak Ridge, TN (United States)
  3. Univ. of Toronto, Toronto, ON (Canada)
  4. TU Wein, Vienna (Austria)
  5. Forschungszentrum Julich GmbH, Julich (Germany)
  6. General Atomics, San Diego, CA (United States); Chinese Academy of Sciences (CAS), Anhui (People's Republic of China)
  7. General Atomics, San Diego, CA (United States)
  8. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  9. Univ. of Californa San Diego, La Jolla, CA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0029-5515; 613827
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 56; Journal Issue: 1; Journal ID: ISSN 0029-5515
IOP Science
Research Org:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Country of Publication:
United States