Based on the models describing the behaviour of neoclassical tearing modes (NTMs), fits for the seed-island triggered excitation and disappearance of these modes at small β-values have been tested for an extended parameter range in the ρpi*–ii plane in ASDEX Upgrade.The disappearance of NTMs at the marginal βp,marg during power ramp-down phases provides input for a direct comparison with models without the influence of the seed-island size. It has been found that for low q95 the NTM remains present until the HL-transition, whereas for higher q95 the mode decays well in H-mode. Scalings for the onset and the marginal βp for the (3/2)-NTM and the analysis of marginal βp for the (2/1)-NTM are presented.
Cross–machine benchmarking for ITER of neoclassical tearing mode stabilization by electron cyclotron current drive