Impurity transport study based on measurement of visible wavelength high-n charge exchange transitions at W7-X
Swee, Colin and Geiger, Benedikt and Ford, Oliver and Nornberg, Mark and O’Mullane, Martin and Poloskei, Peter and Reimold, Felix and Romba, Thilo and Wegner, Thomas, the W7-X Team (2024) Impurity transport study based on measurement of visible wavelength high-n charge exchange transitions at W7-X. Nuclear Fusion, 64 (8). 086062. ISSN 0029-5515 (https://doi.org/10.1088/1741-4326/ad5aad)
Preview |
Text.
Filename: Swee-etal-NF-2024-Impurity-transport-study-based-on-measurement-of-visible-wavelength.pdf
Final Published Version License: Download (5MB)| Preview |
Abstract
A recently installed high-speed charge exchange diagnostic at the W7-X stellarator has been used to identify several high-n Rydberg emission lines near 500 nm following impurity injections. The wavelengths of observed high-n Rydberg transitions are independent of the impurity species and originate from ions with ionization states ranging from 14+ to 45+ suggesting that this approach can be applied to a variety of heavy impurities. Moreover, little to no passive signal is observed since the high-n energy levels are unlikely to be populated by electron impact excitation. The combination of the newly developed diagnostic and the observation of high-n Rydberg states provides spatially resolved, high-speed measurements of multiple charge states which are analyzed in a Bayesian inference framework to determine both impurity diffusion and convection profiles. Measurements from the 2023 experimental campaign conclusively show high diffusion and an inward pinch in the core, well above predictions by neoclassical theory.
ORCID iDs
Swee, Colin, Geiger, Benedikt, Ford, Oliver, Nornberg, Mark, O’Mullane, Martin ORCID: https://orcid.org/0000-0002-2160-4546, Poloskei, Peter, Reimold, Felix, Romba, Thilo and Wegner, Thomas;-
-
Item type: Article ID code: 89932 Dates: DateEvent1 August 2024Published11 July 2024Published Online21 June 2024Accepted16 November 2023SubmittedSubjects: Science > Physics > Nuclear and particle physics. Atomic energy. Radioactivity Department: Faculty of Science > Physics Depositing user: Pure Administrator Date deposited: 16 Jul 2024 13:34 Last modified: 01 Oct 2024 15:21 URI: https://strathprints.strath.ac.uk/id/eprint/89932