Fusion by beam ions in a low collisionality, high mirror ratio magnetic mirror. (1st December 2022)

• Record Type: Journal Article
• Authors: Egedal, J.; Endrizzi, D.; Forest, C.B.; Fowler, T.K.
• Is Part Of: Nuclear fusion. Volume 62:Number 12(2022)
• Publication Date: 2022-12-01
• Subjects: neutral beams -- magnetic mirror -- Fokker–Planck model; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/1741-4326/ac99ec
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: The classical problem of neutral beam ions slowing down in a magnetic mirror geometry is revisited to provide predictive capability for the new Wisconsin HTS Axisymmetric Mirror under development at the University of Wisconsin. A Fokker–Planck model named fast beam ion solver (FBIS) is developed to include the spatial non-uniformity of a physical mirror geometry. The mathematical framework allows for efficient orbit averaging of the pitch-angle scattering operator, and permits a determination of the axial profile of the ambipolar potential confining the electrons. The numerical results from FBIS are consistent with earlier work, but further show how mirror-ratio and a near square magnetic well optimizes the fusion gain. The numerical results are also applied to inform the conceptual design of WHAM++, a low capital-cost breakeven-class magnetic mirror device.