Experimental validation of a model for particle recycling and tungsten erosion during ELMs in the DIII-D divertor
A refined version of the Fundamenksi-Moulton 'free-streaming' model (FSM) for the dynamics of divertor density, particle flux, and heat flux during edge localized modes (ELMs) is presented. This model depends only on inter-ELM pedestal and divertor conditions and, crucially, incorporates particle recycling: a FSM with recycling model, FSRM. The effective particle recycling coefficient, Reff, is the only empirical fitting parameter in the FSRM. The predictions of the FSRM are systematically tested against a DIII-D database of ELM ion and energy fluence measurements and are shown to be consistent with the model across a wide range of pedestal and divertor conditions using a constant value of 0.96 for Reff. Predictions for W sputtering during ELMs are developed based on the FSRM. It is concluded that energetic free-streaming D+ ions and C6+ impurities are the dominant contributors to the intra-ELM gross erosion of W in the DIII-D divertor, i.e., recycling ions and impurities have relatively little impact on the total W sputtering rate. Furthermore, these calculations are also shown to be consistent with spectroscopic measurements of W gross erosion for three different pedestal conditions after incorporating the strong electron density dependence of the WI 400.8 nm ionizations/photon (S/XB) coefficient.
- Research Organization:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC)
- Grant/Contract Number:
- FC02-04ER54698; AC52-07NA27344; AC05-00OR22725; FG02-07ER54917
- OSTI ID:
- 1481034
- Alternate ID(s):
- OSTI ID: 1482814; OSTI ID: 1528702; OSTI ID: 1890826
- Report Number(s):
- LLNL-JRNL-839095; S2352179118300772; PII: S2352179118300772
- Journal Information:
- Nuclear Materials and Energy, Journal Name: Nuclear Materials and Energy Vol. 17 Journal Issue: C; ISSN 2352-1791
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
Web of Science
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