Kinetic-ballooning-limited pedestals in spherical tokamak plasmas
| Autor: | J.F. Parisi, W. Guttenfelder, A.O. Nelson, R. Gaur, A. Kleiner, M. Lampert, G. Avdeeva, J.W. Berkery, C. Clauser, M. Curie, A. Diallo, W. Dorland, S.M. Kaye, J. McClenaghan, F.I. Parra |
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| Jazyk: | angličtina |
| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | Nuclear Fusion, Vol 64, Iss 5, p 054002 (2024) |
| Druh dokumentu: | article |
| ISSN: | 1741-4326 0029-5515 |
| DOI: | 10.1088/1741-4326/ad39fb |
| Popis: | A theoretical model is presented that for the first time matches experimental measurements of the pedestal width-height Diallo scaling in the low-aspect-ratio high- β tokamak NSTX. Combining linear gyrokinetics with self-consistent pedestal equilibrium variation, kinetic-ballooning, rather than ideal-ballooning plasma instability, is shown to limit achievable confinement in spherical tokamak pedestals. Simulations are used to find the novel Gyrokinetic Critical Pedestal constraint, which determines the steepest pressure profile a pedestal can sustain subject to gyrokinetic instability. Gyrokinetic width-height scaling expressions for NSTX pedestals with varying density and temperature profiles are obtained. These scalings for STs depart significantly from that of conventional aspect ratio tokamaks. |
| Databáze: | Directory of Open Access Journals |
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