The role of plasma–atom and molecule interactions on power & particle balance during detachment on the MAST Upgrade Super-X divertor
Verhaegh, K. and Lipschultz, B. and Harrison, J.R. and Federici, F. and Moulton, D. and Lonigro, N. and Kobussen, S.P. and O’Mullane, M. and Osborne, N. and Ryan, P. and Wijkamp, T. and Kool, B. and Rose, E. and Theiler, C. and Thornton, A.J., the MAST Upgrade Team (2023) The role of plasma–atom and molecule interactions on power & particle balance during detachment on the MAST Upgrade Super-X divertor. Nuclear Fusion, 63 (12). 126023. ISSN 0029-5515 (https://doi.org/10.1088/1741-4326/acf946)
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Abstract
This paper shows first quantitative analysis of the detachment processes in the MAST Upgrade Super-X divertor (SXD). We identify an unprecedented impact of plasma-molecular interactions involving molecular ions (likely D2+ ), resulting in strong ion sinks (Molecular Activated Recombination—MAR), leading to a reduction of ion target flux. The MAR ion sinks exceed the divertor ion sources before electron-ion recombination (EIR) starts to occur, suggesting that significant ionisation occurs outside of the divertor chamber. In the EIR region, Te≪0.2 eV is observed and MAR remains significant in these deep detached phases. The total ion sink strength demonstrates the capability for particle (ion) exhaust in the Super-X Configuration. Molecular Activated Dissociation is the dominant volumetric neutral atom creation process can lead to an electron cooling of 20% of PSOL . The measured total radiative power losses in the divertor chamber are consistent with inferred hydrogenic radiative power losses. This suggests that intrinsic divertor impurity radiation, despite the carbon walls, is minor in the divertor chamber. This contrasts previous TCV results, which may be associated with enhanced plasma-neutral interactions and reduced chemical erosion in the detached, tightly baffled SXD. The above observations have also been observed in higher heat flux (narrower SOL width) type I ELMy H-mode discharges. This provides evidence that the characterisation in this paper may be general.
ORCID iDs
Verhaegh, K., Lipschultz, B., Harrison, J.R., Federici, F., Moulton, D., Lonigro, N., Kobussen, S.P., O’Mullane, M. ORCID: https://orcid.org/0000-0002-2160-4546, Osborne, N., Ryan, P., Wijkamp, T., Kool, B., Rose, E., Theiler, C. and Thornton, A.J.;-
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Item type: Article ID code: 86905 Dates: DateEvent1 December 2023Published4 October 2023Published Online13 September 2023Accepted16 June 2023SubmittedSubjects: Science > Physics > Atomic physics. Constitution and properties of matter
Science > Physics > Nuclear and particle physics. Atomic energy. RadioactivityDepartment: Faculty of Science > Physics Depositing user: Pure Administrator Date deposited: 10 Oct 2023 10:36 Last modified: 30 Aug 2024 01:15 URI: https://strathprints.strath.ac.uk/id/eprint/86905