title: Loss of second-ballooning stability in three-dimensional equilibria.
abstract: The effect of three-dimensional geometry on the stability boundaries of ideal ballooning modes is investigated. In particular, the relationship between the symmetry properties of the local shear and the magnetic curvature is addressed for quasisymmetric configurations. The presence of symmetry breaking terms in the local shear can produce localized ballooning instabilities in regions of small average magnetic shear which lower first-ballooning stability thresholds and can potentially eliminate the second stability regime.
authors.affiliation: Department of Physics, University of Wisconsin, Madison, Wisconsin 53706-1687, USA.
authors.forename: C C
authors.initials: CC
authors.lastname: Hegna
authors.forename: S R
authors.initials: SR
authors.lastname: Hudson