Theiler, C., Lipschultz, B. orcid.org/0000-0001-5968-3684, Harrison, J. et al. (17 more authors) (2017) Results from recent detachment experiments in alternative divertor configurations on TCV. Nuclear Fusion. 072008. ISSN 1741-4326
Abstract
Divertor detachment is explored on the TCV tokamak in alternative magnetic geometries. Starting from typical TCV single-null shapes, the poloidal flux expansion at the outer strikepoint is varied by a factor of 10 to investigate the X-divertor characteristics, and the total flux expansion is varied by 70% to study the properties of the super-X divertor. The effect of an additional X-point near the target is investigated in X-point target divertors. Detachment of the outer target is studied in these plasmas during Ohmic density ramps and with the ion ∇B drift away from the primary X-point. The detachment threshold, depth of detachment, and the stability of the radiation location are investigated using target measurements from the wall-embedded Langmuir probes and two-dimensional CIII line emissivity profiles across the divertor region, obtained from inverted, toroidally-integrated camera data. It is found that increasing poloidal flux expansion results in a deeper detachment for a given line-averaged density and a reduction in the radiation location sensitivity to core density, while no large effect on the detachment threshold is observed. The total flux expansion, contrary to expectations, does not show a significant influence on any detachment characteristics in these experiments. In X-point target geometries, no evidence is found for a reduced detachment threshold despite a 2-3 fold increase in connection length. A reduced radiation location sensitivity to core plasma density in the vicinity of the target X-point is suggested by the measurements.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017, Ecole Polytechnique Federale de Lausanne. |
Keywords: | Alternative divertors,Detachment,Super-X divertor,X-divertor,X-point target divertor |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 11 Jul 2017 13:00 |
Last Modified: | 16 Oct 2024 13:54 |
Published Version: | https://doi.org/10.1088/1741-4326/aa5fb7 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1088/1741-4326/aa5fb7 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:118942 |
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