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DOE OSTI · 3682511

SOLPS-ITER modeling of a dedicated divertor for negative triangularity operation on DIII-D

Lore, Jeremy [ORNL] (ORCID:000000029192465X)·Scotti, Filippo [Lawrence Livermore National Laboratory (LLNL)]·Marinoni, Alessandro [University of California, San Diego] (ORCID:0000000310045782)·Thome, K. E. [General Atomics, San Diego]·Lasnier, C. J. [Lawrence Livermore National Laboratory (LLNL)]·Shafer, Morgan [ORNL] (ORCID:0000000198086305)·Truong, D [Lawrence Livermore National Laboratory (LLNL)]·Wang, H.Q. [General Atomics, DIII-D Facility, San Diego, CA]
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Abstract

The design of a new dedicated divertor for negative triangularity (NT) operation on DIII-D with neutral baffles and pumping is informed by SOLPS-ITER transport modeling. This dedicated NT divertor is the latest step in a progression of NT shapes with various divertor characteristics explored on DIII-D, including NT shapes at reduced triangularity and a campaign with stronger shaping that included new armored components on the outboard side. SOLPS simulations played a key role in these divertor designs. Interpretive simulations, using cross-field diffusivities constrained by experimental data in the NT Shelf shape were used to inform the design of the 2023 armor campaign components. A similar procedure used armor campaign data to predict conditions for the dedicated NT divertor. The predictive simulations were used to assess the divertor fluxes, detachment threshold, pumped flux, and neutral leakage. For the dedicated NT divertor, SOLPS simulations and two-point-modeling were used to show the relative impact of magnetic topology (mainly longer connection length) and divertor closure on the divertor conditions relative to the armor campaign. It is predicted that the dedicated NT divertor reaches detachment (measured by target ion flux rollover) at a lower upstream density (≈(1.75−−2.4)×1⁢019m−3) as compared to the armor campaign shape. For the preliminary design geometry, divertor closure reduces the neutral leakage by ≈10%. Parametric optimization indicating further ≈20%–60% improvement in the leakage flux and recycled flux crossing the pump entrance is possible for relatively minor changes to the divertor and baffle layout.

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BibTeXRIS

Lore, Jeremy [ORNL] (ORCID:000000029192465X), Scotti, Filippo [Lawrence Livermore National Laboratory (LLNL)], Marinoni, Alessandro [University of California, San Diego] (ORCID:0000000310045782), Thome, K. E. [General Atomics, San Diego], Lasnier, C. J. [Lawrence Livermore National Laboratory (LLNL)], Shafer, Morgan [ORNL] (ORCID:0000000198086305), Truong, D [Lawrence Livermore National Laboratory (LLNL)], Wang, H.Q. [General Atomics, DIII-D Facility, San Diego, CA]. 2026-08-01. SOLPS-ITER modeling of a dedicated divertor for negative triangularity operation on DIII-D. https://doi.org/10.1016/j.fusengdes.2026.115987

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