Determination of the safety factor profile in TORE SUPRA from the largest striations observed during pellet ablation

Abstract

The largest striations in Hα(Dα) light observed across the ablation cloud of injected hydrogen pellets can be explained in most cases by the presence of resonant magnetic surfaces. The authors suggest that it is possible to identify these striations and therefore to obtain a very detailed profile of the safety factor. This q profile exhibits shear plateaus related to rational q values, thus indicating the presence of magnetic turbulence