Physics:Quasi-isodynamic stellarators
Quasi-isodynamic (QI) stellarators are a class of magnetic confinement fusion reactor which satisfy the property of omnigeneity, avoid the potentially hazardous toroidal bootstrap current, and have minimal neoclassical transport in the collisionless regime.[1]
Wendelstein 7-X, the largest stellarator in the world, was designed to be roughly quasi-isodynamic (QI).
In contrast to quasi-symmetric fields,[2] exactly QI fields on flux surfaces cannot be expressed analytically.[3] However, it has been shown that nearly-exact QI can be extremely well approximated through mathematical optimization,[4] and that the resulting fields enjoy the aforementioned properties.
In a QI field, level curves of the magnetic field strength [math]\displaystyle{ B }[/math] on a flux surface close poloidally (the short way around the torus), and not toroidally (the long way around), causing the stellarator to resemble a series of linked magnetic mirrors.
References
- ↑ Helander, Per; Nührenberg, Jurgen (February 2009). "Bootstrap current and neoclassical transport in quasi-isodynamic stellarators" (in en). Plasma Physics and Controlled Fusion 51 (5): 055004. doi:10.1088/0741-3335/51/5/055004. Bibcode: 2009PPCF...51e5004H. https://iopscience.iop.org/article/10.1088/0741-3335/51/5/055004.
- ↑ Boozer, Allen H. (1983). "Transport and isomorphic equilibria" (in en). Physics of Fluids 26 (2): 496–499. doi:10.1063/1.864166. Bibcode: 1983PhFl...26..496B. https://aip.scitation.org/doi/10.1063/1.864166.
- ↑ Cary, John R.; Shasharina, Svetlana G. (September 1997). "Omnigenity and quasihelicity in helical plasma confinement systems" (in en). Physics of Plasmas 4 (9): 3323–3333. doi:10.1063/1.872473. ISSN 1070-664X. Bibcode: 1997PhPl....4.3323C. http://aip.scitation.org/doi/10.1063/1.872473.
- ↑ Goodman, Alan et al. (September 2023). "Constructing precisely quasi-isodynamic magnetic fields" (in en). Journal of Plasma Physics 89 (5): 905890504. doi:10.1017/S002237782300065X. Bibcode: 2023JPlPh..89e9004G.
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