Title: Impact of ELM control techniques on tungsten sputtering in the DIII-D divertor and extrapolations to ITER

Abstract

The free-streaming plus recycling model (FSRM) has recently been developed to understand and predict tungsten gross erosion rates from the divertor during edge localized modes (ELMs). In this work, the FSRM was tested against experimental measurements of W sputtering during ELMs, conducted via fast WI spectroscopy. Good agreement is observed using a variety of controlling techniques, including gas puffing, neutral beam heating, and plasma shaping to modify the pedestal stability boundary and thus the ELM behavior. ELM mitigation by pellet pacing was observed to strongly reduce W sputtering by flushing C impurities from the pedestal and reducing the divertor target electron temperature. No reduction of W sputtering was observed during the application of resonant magnetic perturbations (RMPs), in contrast to the prediction of the FSRM. Potential sources of this discrepancy are discussed. Finally, the framework of the FSRM is utilized to predict intra-ELM W sputtering rates in ITER. It is concluded that W erosion during ELMs in ITER will be caused mainly by free-streaming fuel ions, but free-streaming seeded impurities (N or Ne) may increase the erosion rate significantly if present in the pedestal at even the 1% level. Impurity recycling is not expected to cause significant W erosion inmore » ITER due to the very low target electron temperature.« less

Authors:

Abrams, Tyler  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-9605-6871"

Unterberg, Ezekial A.  ^[2];

• Search DOE PAGES for author "Unterberg, Ezekial A."
• Search DOE PAGES for ORCID "0000-0003-1353-8865"

Rudakov, D. L.  ^[3];

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• Search DOE PAGES for ORCID "0000-0002-5266-4269"

Leonard, A. W.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-9356-1074"

Schmitz, Oliver  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-9580-9149"

Shiraki, Daisuke  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-1452-6949"

Baylor, Larry R.  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-0325-7771"

Stangeby, Peter C.  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-3511-2286"

Thomas, D. M.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-1217-7773"

Wang, H. Q.  ^[1]

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• Search DOE PAGES for ORCID "0000-0003-1920-2799"

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+ Show Author Affiliations

1. General Atomics, San Diego, CA (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. Univ. of California, San Diego, CA (United States)
4. Univ. of Wisconsin, Madison, WI (United States)
5. Univ. of Toronto, ON (Canada)

Publication Date:

Mon Jun 10 00:00:00 EDT 2019

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); General Atomics, San Diego, CA (United States)

Sponsoring Org.:

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

OSTI Identifier:

1561609

Alternate Identifier(s):

OSTI ID: 1525522; OSTI ID: 1569625

Grant/Contract Number:  

AC05-00OR22725; FC02-04ER54698; FG02-07ER54917; SC0013911; AC04-94AL8500; AC05-06OR23100

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Plasmas

Additional Journal Information:

Journal Volume: 26; Journal Issue: 6; Conference: 60. Annual Meeting of the APS Division of Plasma Physics, Portland, OR (United States), 5-9 Nov 2018; Journal ID: ISSN 1070-664X

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY