Divertor shaping with neutral baffling as a solution to the tokamak power exhaust challenge

Abstract Exhausting power from the hot fusion core to the plasma-facing components is one fusion energy’s biggest challenges. The MAST Upgrade tokamak uniquely integrates strong containment of neutrals within the exhaust area (divertor) with extreme divertor shaping capability. By systematically alt...

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Main Authors: Kevin Verhaegh, James Harrison, David Moulton, Bruce Lipschultz, Nicola Lonigro, Nick Osborne, Peter Ryan, Christian Theiler, Tijs Wijkamp, Dominik Brida, Cyd Cowley, Gijs Derks, Rhys Doyle, Fabio Federici, Bob Kool, Olivier Février, Antti Hakola, Stuart Henderson, Holger Reimerdes, Andrew Thornton, Nicola Vianello, Marco Wischmeier, Lingyan Xiang, the EUROfusion Tokamak Exploitation Team, the MAST Upgrade Team
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Communications Physics
Online Access:https://doi.org/10.1038/s42005-025-02121-1
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author Kevin Verhaegh
James Harrison
David Moulton
Bruce Lipschultz
Nicola Lonigro
Nick Osborne
Peter Ryan
Christian Theiler
Tijs Wijkamp
Dominik Brida
Cyd Cowley
Gijs Derks
Rhys Doyle
Fabio Federici
Bob Kool
Olivier Février
Antti Hakola
Stuart Henderson
Holger Reimerdes
Andrew Thornton
Nicola Vianello
Marco Wischmeier
Lingyan Xiang
the EUROfusion Tokamak Exploitation Team
the MAST Upgrade Team
author_facet Kevin Verhaegh
James Harrison
David Moulton
Bruce Lipschultz
Nicola Lonigro
Nick Osborne
Peter Ryan
Christian Theiler
Tijs Wijkamp
Dominik Brida
Cyd Cowley
Gijs Derks
Rhys Doyle
Fabio Federici
Bob Kool
Olivier Février
Antti Hakola
Stuart Henderson
Holger Reimerdes
Andrew Thornton
Nicola Vianello
Marco Wischmeier
Lingyan Xiang
the EUROfusion Tokamak Exploitation Team
the MAST Upgrade Team
author_sort Kevin Verhaegh
collection DOAJ
description Abstract Exhausting power from the hot fusion core to the plasma-facing components is one fusion energy’s biggest challenges. The MAST Upgrade tokamak uniquely integrates strong containment of neutrals within the exhaust area (divertor) with extreme divertor shaping capability. By systematically altering the divertor shape, this study shows the strongest evidence to date to our knowledge that long-legged divertors with a high magnetic field gradient (total flux expansion) deliver key power exhaust benefits without adversely impacting the hot fusion core. These benefits are already achieved with relatively modest geometry adjustments that are more feasible to integrate in reactor designs. Benefits include reduced target heat loads and improved access to, and stability of, a neutral gas buffer that ‘shields’ the target and enhances power exhaust (detachment). Analysis and model comparisons shows these benefits are obtained by combining multiple shaping aspects: long-legged divertors have expanded plasma-neutral interaction volume that drive reductions in particle and power loads, while total flux expansion enhances detachment access and stability. Containing the neutrals in the exhaust area with physical structures further augments these shaping benefits. These results demonstrate strategic variation in the divertor geometry and magnetic topology is a potential solution to one of fusion’s power exhaust challenge.
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spelling doaj-art-16b9c082b1ff4d95a5a93af8d7c2d3132025-08-20T03:08:42ZengNature PortfolioCommunications Physics2399-36502025-05-018111510.1038/s42005-025-02121-1Divertor shaping with neutral baffling as a solution to the tokamak power exhaust challengeKevin Verhaegh0James Harrison1David Moulton2Bruce Lipschultz3Nicola Lonigro4Nick Osborne5Peter Ryan6Christian Theiler7Tijs Wijkamp8Dominik Brida9Cyd Cowley10Gijs Derks11Rhys Doyle12Fabio Federici13Bob Kool14Olivier Février15Antti Hakola16Stuart Henderson17Holger Reimerdes18Andrew Thornton19Nicola Vianello20Marco Wischmeier21Lingyan Xiang22the EUROfusion Tokamak Exploitation Teamthe MAST Upgrade TeamUnited Kingdom Atomic Energy AuthorityUnited Kingdom Atomic Energy AuthorityUnited Kingdom Atomic Energy AuthorityYork Plasma Institute, University of YorkUnited Kingdom Atomic Energy AuthorityUnited Kingdom Atomic Energy AuthorityUnited Kingdom Atomic Energy AuthoritySwiss Plasma Centre, École Polytechnique Fédérale de LausanneEindhoven University of TechnologyMax Planck Institute for Plasma PhysicsUnited Kingdom Atomic Energy AuthorityEindhoven University of TechnologyDublin City UniversityOak Ridge National LaboratoryEindhoven University of TechnologySwiss Plasma Centre, École Polytechnique Fédérale de LausanneVTT Technical Research Centre of FinlandUnited Kingdom Atomic Energy AuthoritySwiss Plasma Centre, École Polytechnique Fédérale de LausanneUnited Kingdom Atomic Energy AuthorityConsorzio RFXMax Planck Institute for Plasma PhysicsUnited Kingdom Atomic Energy AuthorityAbstract Exhausting power from the hot fusion core to the plasma-facing components is one fusion energy’s biggest challenges. The MAST Upgrade tokamak uniquely integrates strong containment of neutrals within the exhaust area (divertor) with extreme divertor shaping capability. By systematically altering the divertor shape, this study shows the strongest evidence to date to our knowledge that long-legged divertors with a high magnetic field gradient (total flux expansion) deliver key power exhaust benefits without adversely impacting the hot fusion core. These benefits are already achieved with relatively modest geometry adjustments that are more feasible to integrate in reactor designs. Benefits include reduced target heat loads and improved access to, and stability of, a neutral gas buffer that ‘shields’ the target and enhances power exhaust (detachment). Analysis and model comparisons shows these benefits are obtained by combining multiple shaping aspects: long-legged divertors have expanded plasma-neutral interaction volume that drive reductions in particle and power loads, while total flux expansion enhances detachment access and stability. Containing the neutrals in the exhaust area with physical structures further augments these shaping benefits. These results demonstrate strategic variation in the divertor geometry and magnetic topology is a potential solution to one of fusion’s power exhaust challenge.https://doi.org/10.1038/s42005-025-02121-1
spellingShingle Kevin Verhaegh
James Harrison
David Moulton
Bruce Lipschultz
Nicola Lonigro
Nick Osborne
Peter Ryan
Christian Theiler
Tijs Wijkamp
Dominik Brida
Cyd Cowley
Gijs Derks
Rhys Doyle
Fabio Federici
Bob Kool
Olivier Février
Antti Hakola
Stuart Henderson
Holger Reimerdes
Andrew Thornton
Nicola Vianello
Marco Wischmeier
Lingyan Xiang
the EUROfusion Tokamak Exploitation Team
the MAST Upgrade Team
Divertor shaping with neutral baffling as a solution to the tokamak power exhaust challenge
Communications Physics
title Divertor shaping with neutral baffling as a solution to the tokamak power exhaust challenge
title_full Divertor shaping with neutral baffling as a solution to the tokamak power exhaust challenge
title_fullStr Divertor shaping with neutral baffling as a solution to the tokamak power exhaust challenge
title_full_unstemmed Divertor shaping with neutral baffling as a solution to the tokamak power exhaust challenge
title_short Divertor shaping with neutral baffling as a solution to the tokamak power exhaust challenge
title_sort divertor shaping with neutral baffling as a solution to the tokamak power exhaust challenge
url https://doi.org/10.1038/s42005-025-02121-1
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