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

Abstract. The influence of rotation on the (m,n)=(3,2) neoclassical tearing mode onset and the marginal point at ASDEX Upgrade is investigated. In this context the different trigger mechanisms have been 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 NTM stability has been analysed. The existence of an upper NTM onset threshold can be observed in correlation with the rotation normalised to the Alfvén velocity. It can also clearly be verified that at ASDEX Upgrade the NTM onset threshold increases with co-and counter-current directed rotation and also with positive and negative rotation gradient. Submitted to: Plasma Phys. Control. Fusion Influence of rotation on the (m,n)=(3,2) NTM threshold in ASDEX Upgrade