Title: Modeling of inter- and intra-edge-localized mode tungsten erosion during DIII-D H-mode discharges

Abstract

The relationship between the tungsten gross erosion and the ELM characteristics is investigated for high performance (H-mode) discharges during the dedicated Metal Rings Campaign in DIII-D, using the one-dimensional ‘free-streaming’ ELM model, coupled to a simple analytical TRIM.SP sputtering model, while the OEDGE code is employed to calculate the inter-ELM impurity distribution and tungsten gross erosion. A carbon-tungsten mixed target material is used for both inter- and intra-ELM simulations. The OEDGE results reveal that the inter-ELM tungsten gross erosion rate is not sensitive to the carbon fraction on the tungsten surface layer; a wider range of carbon fractions from 0.3 to 0.6 give similar tungsten gross erosion profiles and match the diagnostic data, which is consistent with the simple analytical model. However, the intra-ELM simulation indicates that the value of surface carbon fraction can be as low as 0.3 to reproduce the measured tungsten gross erosion during ELMs, based on the effective ionizations/photon (S/XB) value of WI emissions. Finally, for both inter- and intra-ELM cases, carbon is predicted to dominate the tungsten erosion. However, in contrast to the inter-ELM tungsten erosion, which is dominated by locally redeposited C²⁺, the energetic C⁶⁺ originating from the pedestal can contribute substantial tungsten erosionmore » in the near-separatrix region during ELMs, and the width of this C⁶⁺ dominated region exhibits a negative correlation with the heat flux density carried by ELMs.« less

Authors:

Xu, G. L.  ^[1];

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Guterl, J.  ^[2];

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Abrams, T. ^[3]; Wang, H. Q. ^[3]; Elder, J. D. ^[4]; Unterberg, E. A. ^[5]; Thomas, D. M. ^[3]; Stangeby, P. C.  ^[6];

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Guo, H. Y. ^[3]; Ye, M. Y. ^[7]

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+ Show Author Affiliations

1. Univ. of Science and Technology of China, Hefei (China). School of Physical Science; Shenzhen Univ. (China). College of Physics and Optoelectronic Engineering
2. Oak Ridge Associated Univ., Oak Ridge, TN (United States)
3. General Atomics, San Diego, CA (United States)
4. Univ. of Toronto (Canada). Inst. for Aerospace Studies
5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
6. General Atomics, San Diego, CA (United States); Univ. of Toronto (Canada). Inst. for Aerospace Studies
7. Univ. of Science and Technology of China, Hefei (China). School of Physical Science

Publication Date:

2019-10-04

Research Org.:

General Atomics, San Diego, CA (United States)

Sponsoring Org.:

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

OSTI Identifier:

1577445

Grant/Contract Number:  

FC02-04ER54698; SC0018423

Resource Type:

Accepted Manuscript

Journal Name:

Nuclear Fusion

Additional Journal Information:

Journal Volume: 59; Journal Issue: 12; Journal ID: ISSN 0029-5515

Publisher:

IOP Science

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma material interaction; tungsten erosion; ELM; fusion