Journal article
Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade
Department of Physics, Technical University of Denmark1
Plasma Physics and Fusion Energy, Department of Physics, Technical University of Denmark2
University of Seville3
Max Planck Institute for Plasma Physics4
Dutch Institute for Fundamental Energy Research5
Budapest University of Technology and Economics6
Sawtooth instabilities can modify heating and current-drive profiles and potentially increase fast-ion losses. Understanding how sawteeth redistribute fast ions as a function of sawtooth parameters and of fast-ion energy and pitch is hence a subject of particular interest for future fusion devices. Here we present the first collective Thomson scattering (CTS) measurements of sawtooth-induced redistribution of fast ions at ASDEX Upgrade.
These also represent the first localized fast-ion measurements on the high-field side of this device. The results indicate fast-ion losses in the phase-space measurement volume of about 50% across sawtooth crashes, in good agreement with values predicted with the Kadomtsev sawtooth model implemented in TRANSP and with the sawtooth model in the EBdyna_go code.
In contrast to the case of sawteeth, we observe no fast-ion redistribution in the presence of fishbone modes. We highlight how CTS measurements can discriminate between different sawtooth models, in particular when aided by multi-diagnostic velocity-space tomography, and briefly discuss our results in light of existing measurements from other fast-ion diagnostics.
Language: | English |
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Publisher: | IOP Publishing |
Year: | 2016 |
Pages: | 112014 |
ISSN: | 10185577 , 00295515 and 17414326 |
Types: | Journal article |
DOI: | 10.1088/0029-5515/56/11/112014 |
ORCIDs: | Rasmussen, Jesper , Nielsen, Stefan Kragh , Pedersen, Morten Stejner , Korsholm, Søren Bang , Leipold, Frank and Salewski, Mirko |