http://arxiv.org/abs/1909.07910
In an inhomogeneous plasma, the ideal magnetohydrodynamics model gives rise to the Alfv\'{e}n continuum, consisting of non-square-integrable improper eigenfunctions. For a gravitating slab, we calculate a Chern number for the Alfv\'{e}n continuum on a given magnetic surface. For strong magnetic shear, the Chern number is equal to $\pm 1$, depending on the sign of the shear. By appeal to the bulk-boundary correspondence, this result suggests a topological character of the reversed-shear Alfv\'{e}n eigenmode, which has been observed in tokamaks and is radially localized to layers of zero magnetic shear. As a result, the reversed-shear Alfv\'{e}n eigenmode may be topologically robust to three-dimensional perturbations such as magnetic islands.
J. Parker, J. Burby, J. Marston, et. al.
Wed, 18 Sep 19
19/64
Comments: 5 pages, 2 figures