Title: Predicting tungsten erosion and leakage properties for the new V-shaped small angle slot divertor in DIII-D

Abstract

Impurity transport modeling of the new tungsten (W)-coated, V-shaped small angle slot (SAS) divertor in the DIII-D tokamak was conducted using the SOLPS-ITER plasma edge code package and the DIVIMP impurity tracking code. The inboard baffle of the current SAS divertor will be shifted closer to the outboard baffle, creating a V-corner at the slot vertex. In addition, the outboard baffle will be coated with 10–15 μm of W for experiments studying high-Z sourcing and leakage in a closed divertor. Modeling of the 'SAS-VW' divertor predicts that these changes to the inner baffle will reduce W gross erosion by 40× relative to the existing SAS divertor when the outer strike point (OSP) is at the V-corner and the ion B × ∇B drift is towards the divertor, driven primarily by significant cooling near the slot vertex. Most W erosion in SAS-VW is expected to occur near the slot entrance, which may pose a higher risk to core contamination than W eroded deeper in the slot. Furthermore, adding a new sheath-based prompt redeposition model increases the sensitivity of redeposition estimates to near-target plasma conditions and may provide more accurate predictions of net erosion. Moving the OSP outboard from the slot vertexmore » ~4 cm onto the W-coated region yields a 40× increase in the gross erosion rate and a 50% decrease in the core leakage fraction. Thus slight variations in strike point location may counteract the potential benefits of the tightly-baffled V slot on minimizing erosion. This impurity transport modeling provides useful guidance for future experiments on the SAS-VW divertor focused on high-Z erosion/redeposition, scrape-off layer transport, and core leakage.« less

Authors:

Sinclair, G.  ^[1];

• Search DOE PAGES for author "Sinclair, G."
• Search DOE PAGES for ORCID "0000-0003-4195-177X"

Maurizio, R.  ^[1];

• Search DOE PAGES for author "Maurizio, R."
• Search DOE PAGES for ORCID "0000-0001-9896-6732"

Ma, X.  ^[1];

• Search DOE PAGES for author "Ma, X."
• Search DOE PAGES for ORCID "0000-0002-7326-2146"

Abrams, T.  ^[1];

• Search DOE PAGES for author "Abrams, T."
• Search DOE PAGES for ORCID "0000-0002-9605-6871"

Elder, J. D. ^[2]; Guo, H. Y. ^[3]; Thomas, D. M.  ^[1];

• Search DOE PAGES for author "Thomas, D. M."
• Search DOE PAGES for ORCID "0000-0002-1217-7773"

Leonard, A. W.  ^[1]

• Search DOE PAGES for author "Leonard, A. W."
• Search DOE PAGES for ORCID "0000-0001-9356-1074"

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+ Show Author Affiliations

1. General Atomics, San Diego, CA (United States)
2. Univ. of Toronto Inst. for Aerospace Studies (Canada)
3. General Atomics, San Diego, CA (United States); ENN Science and Technology Development Co., Ltd, Langfang (China)

Publication Date:

Tue Sep 13 00:00:00 EDT 2022

Research Org.:

General Atomics, San Diego, CA (United States)

Sponsoring Org.:

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

OSTI Identifier:

1971197

Grant/Contract Number:  

FC02-04ER54698

Resource Type:

Accepted Manuscript

Journal Name:

Nuclear Fusion

Additional Journal Information:

Journal Volume: 62; Journal Issue: 10; Journal ID: ISSN 0029-5515

Publisher:

IOP Science

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma-material interactions; SOLPS-ITER; divertor closure; tungsten; erosion; DIII-D