Modeling, analysis, and code/data validation of DIII-D tokamak divertor experiments on ELM and non-ELM plasma tungsten sputtering erosion

Brooks, J. N.; Sizyuk, T.; Elder, J. D.; Abrams, T.; Hassanein, A.; Rudakov, D. L.; Wampler, W.

doi:10.1088/1741-4326/abb39c

Title: Modeling, analysis, and code/data validation of DIII-D tokamak divertor experiments on ELM and non-ELM plasma tungsten sputtering erosion

Journal Article · Wed Oct 14 00:00:00 EDT 2020 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/abb39c· OSTI ID:1832919

Brooks, J. N.;

; Elder, J. D.; Abrams, T.; Hassanein, A.;

;

We analyzed recent DIII-D tokamak tungsten divertor probe experiments using advanced, coupled, sputter erosion/redeposition, plasma, and surface response code packages. Modeling is done for ELM-ing H-mode, and L-mode plasmas, impinging on various size tungsten deposits on Divertor Material Evaluation System (DiMES) carbon probes. The simulations compute 3-D, full kinetic, sub-gyromotion, impurity sputtering and transport, including changes in tungsten surface composition and response due to mixed deuterium and carbon ions irradiation. Per our analysis, ELM plasma sputtering in DIII-D mostly involves free-streaming high energy (~500-1000 eV) D⁺ and C⁺⁶ ions, with high near-surface plasma density. L-Mode sputtering is due to impurity sputtering (C, W) only, with lower density. All cases show complete redeposition of tungsten on the divertor, with significant redeposition on the tungsten spots themselves, and low self-sputtering. Comparison of ELM plasma gross tungsten erosion simulation results with in-situ spectroscopic data is good, as are code/data comparisons of net erosion using post-exposure Rutherford Back Scattering (RBS) data for the L-mode probes. The analysis, extrapolated to a full tungsten divertor, implies low net erosion and negligible plasma contamination from sputtering. These results support the use of high-Z plasma facing surfaces in ITER and beyond.

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Research Organization:: General Atomics, San Diego, CA (United States); Purdue Univ., West Lafayette, IN (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Grant/Contract Number:: Work supported by the U.S. Department of Energy; FC02-04ER54698; SC0020198; AC52-07NA27344; AC04-94AL85000; FG02-07ER54917

OSTI ID:: 1832919

Alternate ID(s):: OSTI ID: 1674974; OSTI ID: 1728657

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Vol. 60 Journal Issue: 12; ISSN 0029-5515

Publisher:: IOP PublishingCopyright Statement

Country of Publication:: IAEA

Language:: English

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