Effects of sawtooth activity in Ignitor

The expected performance of the Ignitor experiment has been investigated by a 1 1/2-D transport code using a profile consistent diffusion model for electron and ion thermal energy. By considering the flattop situation for plasma current and toroidal magnetic field, the influence of the central region behaviour on the fusion prospects has been specifically analyzed. The simulation results, besides confirming the requirement of long sawtooth periods, put in evidence the strong effect of the involved region size: sawteeth can prevent ignition if this region is not sufficiently small. On the other hand this situation should be a degraded scenario as Ignitor is designed to operate under conditions where the n = 1/m = 1 modes, associated with sawtooth crashes, are stable.