Interaction of ITER-like ICRF antenna with Tore Supra plasmas: insight from modelling

The non-linear interaction of ion cyclotron resonance frequency (ICRF) waves with the plasma edge is one of the challenges faced by high power wave heating systems in next step devices. Such interaction is often associated with parallel RF electric fields excited by spurious parallel RF currents flowing on the antenna front face. One way to test this conjecture is to investigate how RF-induced edge perturbations develop spatially around ICRF launchers, for a large variety of RF current flows. In 2007 a novel ICRF ITER-like (IL) antenna was tested on the TS tokamak, offering hence the unique opportunity to document wave-plasma interactions in the tokamak edge, on the same target plasmas as classical antennae, but with different patterns of RF currents on the antenna front face and different points of high RF voltage, thus imposing tighter constraints on interpretative physics models. The present paper confronts theoretical models with selected experimental results and suggests ways to decrease the wave-plasma interaction for a recessed antenna.