Moulton, D., Harrison, J., Lipschultz, B. orcid.org/0000-0001-5968-3684 et al. (1 more author) (2017) Using SOLPS to confirm the importance of total flux expansion in Super-X divertors. Plasma Physics and Controlled Fusion. 065011. ISSN 1361-6587
Abstract
We show that a central characteristic of Super-X divertors, total flux expansion f R (defined as the ratio of the elementary area normal to the magnetic field at the target to that at the X-point), significantly changes the characteristics of the target plasma for fixed upstream conditions. To isolate the effect of total flux expansion from other effects, we utilise SOLPS-5.0 simulations of an isolated slot divertor leg in a minimally complex, rectangular geometry. The grid is rotated outwards about a fixed X-point in order to perform a scan in which only the total flux expansion increases, by means of a decrease in the target magnetic field at higher major radius. We find that if the SOL remains in the attached, conduction-limited regime throughout the scan, the target electron density scales approximately as , while the target electron temperature scales approximately as , in good agreement with the modified two-point model presented in Petrie et al (2013 Nucl. Fusion 53 113024). If, however, the SOL transitions from the sheath-limited regime to the conduction-limited regime during the scan, the simulated scalings of target electron temperature and density are weaker than predicted by the modified two-point model. The upstream density for transition from sheath- to conduction-limited regimes is found to scale approximately with , in agreement with the modified two-point model. Assessing upstream-density-driven detachment onset, we find that the target electron temperature at which target density rollover occurs (∼0.6 eV) is independent of f R. Given this, the modified two-point model predicts a halving of the upstream (and target) densities at which rollover occurs when f R is doubled, in good agreement with the simulation results.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017, IOP Publishing Ltd. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details. |
Keywords: | simplified geometry,SOLPS,Super-X |
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 13:49 |
Published Version: | https://doi.org/10.1088/1361-6587/aa6b13 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1088/1361-6587/aa6b13 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:118941 |
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