Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumping
Predictive design modeling of a Dissipation-Focused Divertor for future operation in DIII-D reveals that increasing the poloidal distance of the pump duct entrance from the target surface along the low-field side divertor baffle increases neutral compression and modifies the spatial distribution of...
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Elsevier
2024-12-01
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| Series: | Nuclear Materials and Energy |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352179124002497 |
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| author | J.H. Yu R.S. Wilcox R. Maurizio A. Holm S.L. Allen W. Choi M.E. Fenstermacher M. Groth A.W. Leonard A.G. McLean F. Scotti M.W. Shafer |
| author_facet | J.H. Yu R.S. Wilcox R. Maurizio A. Holm S.L. Allen W. Choi M.E. Fenstermacher M. Groth A.W. Leonard A.G. McLean F. Scotti M.W. Shafer |
| author_sort | J.H. Yu |
| collection | DOAJ |
| description | Predictive design modeling of a Dissipation-Focused Divertor for future operation in DIII-D reveals that increasing the poloidal distance of the pump duct entrance from the target surface along the low-field side divertor baffle increases neutral compression and modifies the spatial distribution of power dissipation. With a divertor pump located mid-leg between the target and the X-point, SOLPS-ITER boundary plasma simulations without drifts predict the formation of a dense neutral cloud near the target with > 30x higher neutral compression in detachment, a more stable detachment front located further from the target, and ∼25% lower outer midplane separatrix density required for detachment onset, compared to a pump located in the scrape-off layer at the target surface. Up to 19 MW of power flowing into the divertors is modeled using the following two numerical implementations for particle pumping: a specified fraction of particles incident on variable wall sections of the plasma grid is removed from the computational domain (so-called albedo pumping), and a pump duct is modeled which includes dynamics of kinetic neutrals in the duct. The simulations show that the detachment front is located between the divertor target and the X-point and is relatively stable near the pump entrance, without a strong dependence on gas puff rate or injected power. The mid-leg pump design spatially separates the two primary functions of a divertor (power handling and particle exhaust), with the majority of power dissipation occurring near the target plate and particle exhaust taking place further upstream. The benefit of enhanced dissipation using mid-leg pumping comes at the cost of a higher outer midplane separatrix density for a given amount of particle injection. |
| format | Article |
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| institution | Kabale University |
| issn | 2352-1791 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Nuclear Materials and Energy |
| spelling | doaj-art-b1e8fa9c5d79469ab077cda50ab5b85e2024-12-21T04:28:33ZengElsevierNuclear Materials and Energy2352-17912024-12-0141101826Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumpingJ.H. Yu0R.S. Wilcox1R. Maurizio2A. Holm3S.L. Allen4W. Choi5M.E. Fenstermacher6M. Groth7A.W. Leonard8A.G. McLean9F. Scotti10M.W. Shafer11General Atomics, San Diego, 92186 CA, USA; Corresponding author.Oak Ridge National Laboratory, Oak Ridge, 37831 TN, USAGeneral Atomics, San Diego, 92186 CA, USALawrence Livermore National Laboratory, Livermore, 94550 CA, USALawrence Livermore National Laboratory, Livermore, 94550 CA, USAGeneral Atomics, San Diego, 92186 CA, USALawrence Livermore National Laboratory, Livermore, 94550 CA, USAAalto University, Espoo, FinlandGeneral Atomics, San Diego, 92186 CA, USALawrence Livermore National Laboratory, Livermore, 94550 CA, USALawrence Livermore National Laboratory, Livermore, 94550 CA, USAOak Ridge National Laboratory, Oak Ridge, 37831 TN, USAPredictive design modeling of a Dissipation-Focused Divertor for future operation in DIII-D reveals that increasing the poloidal distance of the pump duct entrance from the target surface along the low-field side divertor baffle increases neutral compression and modifies the spatial distribution of power dissipation. With a divertor pump located mid-leg between the target and the X-point, SOLPS-ITER boundary plasma simulations without drifts predict the formation of a dense neutral cloud near the target with > 30x higher neutral compression in detachment, a more stable detachment front located further from the target, and ∼25% lower outer midplane separatrix density required for detachment onset, compared to a pump located in the scrape-off layer at the target surface. Up to 19 MW of power flowing into the divertors is modeled using the following two numerical implementations for particle pumping: a specified fraction of particles incident on variable wall sections of the plasma grid is removed from the computational domain (so-called albedo pumping), and a pump duct is modeled which includes dynamics of kinetic neutrals in the duct. The simulations show that the detachment front is located between the divertor target and the X-point and is relatively stable near the pump entrance, without a strong dependence on gas puff rate or injected power. The mid-leg pump design spatially separates the two primary functions of a divertor (power handling and particle exhaust), with the majority of power dissipation occurring near the target plate and particle exhaust taking place further upstream. The benefit of enhanced dissipation using mid-leg pumping comes at the cost of a higher outer midplane separatrix density for a given amount of particle injection.http://www.sciencedirect.com/science/article/pii/S2352179124002497DIII-DDivertor designSOLPS-ITERTokamakMid-leg pumpingSOL power dissipation |
| spellingShingle | J.H. Yu R.S. Wilcox R. Maurizio A. Holm S.L. Allen W. Choi M.E. Fenstermacher M. Groth A.W. Leonard A.G. McLean F. Scotti M.W. Shafer Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumping Nuclear Materials and Energy DIII-D Divertor design SOLPS-ITER Tokamak Mid-leg pumping SOL power dissipation |
| title | Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumping |
| title_full | Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumping |
| title_fullStr | Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumping |
| title_full_unstemmed | Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumping |
| title_short | Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumping |
| title_sort | simulations of divertor designs that spatially separate power and particle exhaust using mid leg divertor particle pumping |
| topic | DIII-D Divertor design SOLPS-ITER Tokamak Mid-leg pumping SOL power dissipation |
| url | http://www.sciencedirect.com/science/article/pii/S2352179124002497 |
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