Modelling of NTM stabilization by RF heating and current drive in plasma with a stiff temperature profile

Neoclassical Tearing Modes (NTM) must be controlled or suppressed to prevent a degradation of the energy confinement for future devices. This can be done applying RF-current (ECCD) and -heating (ECRH) at the rational surface where the instability appears. The response of the plasma to a localised heating applied for the NTM control is sensitive to the stiffness of the temperature profile, behavior resulting from magnetised plasmas turbulent transport properties.[1] A new criterium for the minimum EC current required to stabilize an NTM is determined from a generalized Rutherford equation that includes heat. A lower ECCD current threshold is obtained when heat is considerd compared to pure ECCD criterion[7]. Background plasma heating decreases, however, the advantage of ECRH. Nonlinear simulations with the XTOR code [6] where a stiff plasma model and RF heating and current drive are implemented confirm the main properties of heating sources on saturation and stabilization, but also the moderate advantage of RF heating in the ITER case.