Comparison of local and global gyrokinetic calculations of collisionless zonal flow damping in quasi-symmetric stellarators
| Autor: | Ivan Calvo, J. Smoniewski, Joseph Talmadge, E. Sánchez, M. J. Pueschel |
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| Přispěvatelé: | Science and Technology of Nuclear Fusion |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Physics
Flux tube Oscillation National Compact Stellarator Experiment FOS: Physical sciences Zonal flow (plasma) Mechanics Condensed Matter Physics 01 natural sciences Physics - Plasma Physics 010305 fluids & plasmas law.invention Plasma Physics (physics.plasm-ph) Helically Symmetric Experiment law 0103 physical sciences Wavenumber Symmetry breaking 010306 general physics Stellarator |
| Zdroj: | Physics of Plasmas, 28, 042503 Physics of Plasmas, 28(4):042503. American Institute of Physics |
| ISSN: | 1070-664X |
| Popis: | The linear collisionless damping of zonal flows is calculated for quasi-symmetric stellarator equilibria in flux-tube, flux-surface, and full-volume geometry. Equilibria are studied from the quasi-helical symmetry configuration of the Helically Symmetric eXperiment (HSX), a broken symmetry configuration of HSX, and the quasi-axial symmetry geometry of the National Compact Stellarator eXperiment (NCSX). Zonal flow oscillations and long-time damping affect the zonal flow evolution, and the zonal flow residual goes to zero for small radial wavenumber. The oscillation frequency and damping rate depend on the bounce-averaged radial particle drift in accordance with theory. While each flux tube on a flux surface is unique, several different flux tubes in HSX or NCSX can reproduce the zonal flow damping from a flux-surface calculation given an adequate parallel extent. The flux-surface or flux-tube calculations can accurately reproduce the full-volume long-time residual for moderate $k_x$, but the oscillation and damping time scales are longer in local representations, particularly for small $k_x$ approaching the system size. Comment: The following article has been accepted by Physics of Plasmas. After it is published, it will be found at https://aip.scitation.org/journal/php. 33 pages, 18 figures |
| Databáze: | OpenAIRE |
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