Chapman, I. T.Walkden, N. R.Graves, J. P.Wahlberg, C.2012-05-042012-05-042012-05-04201110.1088/0741-3335/53/12/125002https://infoscience.epfl.ch/handle/20.500.14299/79966WOS:000298644000045Sheared toroidal rotation is found to increase the ideal external kink stability limit, thought to be the ultimate performance limit in fusion tokamaks. However, at rotation speeds approaching a significant fraction of the Alfv´en speed, the toroidal rotation shear drives a Kelvin–Helmholtz-like global plasma instability. Optimizing the rotation profile to maximize the pressure before encountering external kink modes, but simultaneously avoiding flow-driven instabilities, can lead to a window of stability that might be attractive for operating future high-performance fusion devices such as a spherical tokamak component test facility.text::journal::journal article::research article