Journal article
High-definition velocity-space tomography of fast-ion dynamics
Department of Physics, Technical University of Denmark1
Plasma Physics and Fusion Energy, Department of Physics, Technical University of Denmark2
Max Planck Institute for Plasma Physics3
Department of Applied Mathematics and Computer Science, Technical University of Denmark4
Scientific Computing, Department of Applied Mathematics and Computer Science, Technical University of Denmark5
University of California at Irvine6
University of Milan - Bicocca7
Velocity-space tomography of the fast-ion distribution function in a fusion plasma is usually a photon-starved tomography method due to limited optical access and signal-to-noise ratio of fast-ion Dα (FIDA) spectroscopy as well as the strive for high-resolution images. In high-definition tomography, prior information makes up for this lack of data.
We restrict the target velocity space through the measured absence of FIDA light, impose phase-space densities to be non-negative, and encode the known geometry of neutral beam injection (NBI) sources. We further use a numerical simulation as prior information to reconstruct where in velocity space the measurements and the simulation disagree.
This alternative approach is demonstrated for four-view as well as for two-view FIDA measurements. The high-definition tomography tools allow us to study fast ions in sawtoothing plasmas and the formation of NBI peaks at full, half and one-third energy by time-resolved tomographic movies.
Language: | English |
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Publisher: | IOP Publishing |
Year: | 2016 |
Pages: | 106024 |
ISSN: | 17414326 , 00295515 and 10185577 |
Types: | Journal article |
DOI: | 10.1088/0029-5515/56/10/106024 |
ORCIDs: | Salewski, Mirko , Hansen, Per Christian , Korsholm, Søren Bang , Leipold, Frank , Madsen, Jens , Nielsen, Stefan Kragh , Rasmussen, Jesper and Pedersen, Morten Stejner |