Impact of magnetic X-points on the vertical stability of tokamak plasmas. (1st October 2021)

• Record Type: Journal Article
• Authors: Yolbarsop, A.; Porcelli, F.; Fitzpatrick, R.
• Is Part Of: Nuclear fusion. Volume 61:Number 11(2021)
• Publication Date: 2021-10-01
• Subjects: tokamak plasma macroscopic stability -- axisymmetric MHD modes -- magnetic X-points in tokamaks -- vertical plasma displacements; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/1741-4326/ac27c5
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: The ideal-magneto-hydro-dynamic (MHD) theory of axisymmetric modes with toroidal mode number n = 0 in tokamak plasmas is developed. These modes are resonant at the magnetic X-points of the tokamak divertor separatrix. As a consequence, current sheets form along the separatrix, which profoundly affect the stability of vertical plasma displacements. In particular, current sheets at the magnetic separatrix lead to stabilization of n = 0 modes, at least on the ideal-MHD time scale, adding an important ingredient to the mechanism of passive feedback stabilization.