Direct construction of optimized stellarator shapes. Part 3. Omnigenity near the magnetic axis. (December 2019)

• Record Type: Journal Article
• Authors: Plunk, Gabriel G.; Landreman, Matt; Helander, Per
• Is Part Of: Journal of plasma physics. Volume 85:Number 6(2019)
• Publication Date: 2019-12
• Subjects: fusion plasma, -- plasma confinement, -- plasma devices; Plasma (Ionized gases) -- Periodicals; 530.4405
• DOI: 10.1017/S002237781900062X
• Languages: English
• ISSNs: 0022-3778

Abstract

Abstract : The condition of omnigenity is investigated, and applied to the near-axis expansion of Garren & Boozer ( Phys. Fluids B, vol. 3 (10), 1991 a, pp. 2805–2821). Due in part to the particular analyticity requirements of the near-axis expansion, we find that, excluding quasi-symmetric solutions, only one type of omnigenity, namely quasi-isodynamicity, can be satisfied at first order in the distance from the magnetic axis. Our construction provides a parameterization of the space of such solutions, and the cylindrical reformulation and numerical method of Landreman & Sengupta ( J. Plasma Phys., vol. 84 (6), 2018, 905840616); Landreman et al. ( J. Plasma Phys., vol. 85 (1), 2019, 905850103), enables their efficient numerical construction.