Transport and profile broadening in the private flux region of ASDEX upgrade and role for power exhaust

Understanding the transport processes that determine the plasma profile widths in the scrape-off layer (SOL) and divertor region of tokamaks is crucial for successful power and particle exhaust management in future devices. Plasma transport from the SOL into the private flux region (PFR) broadens th...

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Main Authors: D. Brida, G. Grenfell, O. Grover, D. Silvagni, M. Faitsch, U. Stroth, the ASDEX Upgrade Team, the EUROfusion Tokamak Exploitation Team
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:Nuclear Fusion
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Online Access:https://doi.org/10.1088/1741-4326/adac76
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author D. Brida
G. Grenfell
O. Grover
D. Silvagni
M. Faitsch
U. Stroth
the ASDEX Upgrade Team
the EUROfusion Tokamak Exploitation Team
author_facet D. Brida
G. Grenfell
O. Grover
D. Silvagni
M. Faitsch
U. Stroth
the ASDEX Upgrade Team
the EUROfusion Tokamak Exploitation Team
author_sort D. Brida
collection DOAJ
description Understanding the transport processes that determine the plasma profile widths in the scrape-off layer (SOL) and divertor region of tokamaks is crucial for successful power and particle exhaust management in future devices. Plasma transport from the SOL into the private flux region (PFR) broadens the profiles and could mitigate the power exhaust challenge. Analysis of ion current profiles, measured by Langmuir probes in the ASDEX upgrade (AUG) tokamak, shows that the ion current width in the PFR, normalized by the flux expansion between outer target and midplane, is about 1.2 mm in L-mode and 0.9 mm in inter-ELM H-mode plasmas. The measured widths agree within a factor of two with predictions from an analytical model, based on Pfirsch-Schlüter flows. According to the model, the ion PFR width increases with the distance Δ R between the outer target and X-point major radii, and scales inversely with the poloidal magnetic field $B_\mathrm p$ . For the tokamaks ITER and SPARC the model predicts PFR widths below 0.3 mm.
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institution Kabale University
issn 0029-5515
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publishDate 2025-01-01
publisher IOP Publishing
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series Nuclear Fusion
spelling doaj-art-84567eae6e6d4de38c537e4a5348f21d2025-01-31T10:37:36ZengIOP PublishingNuclear Fusion0029-55152025-01-0165202606510.1088/1741-4326/adac76Transport and profile broadening in the private flux region of ASDEX upgrade and role for power exhaustD. Brida0https://orcid.org/0000-0002-8647-7058G. Grenfell1https://orcid.org/0000-0003-0107-5787O. Grover2https://orcid.org/0000-0002-7695-8050D. Silvagni3https://orcid.org/0000-0003-2103-3592M. Faitsch4https://orcid.org/0000-0002-9809-7490U. Stroth5https://orcid.org/0000-0003-1104-2233the ASDEX Upgrade Team6the EUROfusion Tokamak Exploitation Team7Max-Planck-Institut für Plasmaphysik , Boltzmannstr. 2, 85748 Garching, GermanyMax-Planck-Institut für Plasmaphysik , Boltzmannstr. 2, 85748 Garching, GermanyMax-Planck-Institut für Plasmaphysik , Boltzmannstr. 2, 85748 Garching, GermanyMax-Planck-Institut für Plasmaphysik , Boltzmannstr. 2, 85748 Garching, GermanyMax-Planck-Institut für Plasmaphysik , Boltzmannstr. 2, 85748 Garching, GermanyMax-Planck-Institut für Plasmaphysik , Boltzmannstr. 2, 85748 Garching, GermanyMax-Planck-Institut für Plasmaphysik , Boltzmannstr. 2, 85748 Garching, GermanyMax-Planck-Institut für Plasmaphysik , Boltzmannstr. 2, 85748 Garching, GermanyUnderstanding the transport processes that determine the plasma profile widths in the scrape-off layer (SOL) and divertor region of tokamaks is crucial for successful power and particle exhaust management in future devices. Plasma transport from the SOL into the private flux region (PFR) broadens the profiles and could mitigate the power exhaust challenge. Analysis of ion current profiles, measured by Langmuir probes in the ASDEX upgrade (AUG) tokamak, shows that the ion current width in the PFR, normalized by the flux expansion between outer target and midplane, is about 1.2 mm in L-mode and 0.9 mm in inter-ELM H-mode plasmas. The measured widths agree within a factor of two with predictions from an analytical model, based on Pfirsch-Schlüter flows. According to the model, the ion PFR width increases with the distance Δ R between the outer target and X-point major radii, and scales inversely with the poloidal magnetic field $B_\mathrm p$ . For the tokamaks ITER and SPARC the model predicts PFR widths below 0.3 mm.https://doi.org/10.1088/1741-4326/adac76scrape-off layerdivertorpower exhaustheat flux widthSOL transport
spellingShingle D. Brida
G. Grenfell
O. Grover
D. Silvagni
M. Faitsch
U. Stroth
the ASDEX Upgrade Team
the EUROfusion Tokamak Exploitation Team
Transport and profile broadening in the private flux region of ASDEX upgrade and role for power exhaust
Nuclear Fusion
scrape-off layer
divertor
power exhaust
heat flux width
SOL transport
title Transport and profile broadening in the private flux region of ASDEX upgrade and role for power exhaust
title_full Transport and profile broadening in the private flux region of ASDEX upgrade and role for power exhaust
title_fullStr Transport and profile broadening in the private flux region of ASDEX upgrade and role for power exhaust
title_full_unstemmed Transport and profile broadening in the private flux region of ASDEX upgrade and role for power exhaust
title_short Transport and profile broadening in the private flux region of ASDEX upgrade and role for power exhaust
title_sort transport and profile broadening in the private flux region of asdex upgrade and role for power exhaust
topic scrape-off layer
divertor
power exhaust
heat flux width
SOL transport
url https://doi.org/10.1088/1741-4326/adac76
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