Influence of rotation on the (m, n) = (3,2) neoclassical tearing mode threshold in the ASDEX Upgrade

The influence of rotation on the (m, n) = (3, 2) neoclassical tearing mode onset and the marginal point at the ASDEX Upgrade is investigated. In this context, the different trigger mechanisms are identified and the influence of not only the rotation but also the rotation gradient and the differential rotation between the resonant and the triggering surface on the neoclassical tearing mode (NTM) stability is analysed. The existence of an upper NTM onset threshold can be observed in correlation with the rotation normalized to the Alfven velocity. It can also clearly be verified that at the ASDEX Upgrade the NTM onset threshold increases with co- and counter-current directed rotation and also with positive and negative rotation gradient.