Minimization of the edge modes and near fields of a travelling wave array antenna for WEST

The travelling wave array (TWA) antenna has been proposed as a promising alternative for ion cyclotron resonant heating in future fusion reactors. In this study, the possibility to make a TWA compatible with a tungsten environment like the WEST tokamak is assessed. For this purpose, two aspects of the antenna are investigated: the power spectrum and the near fields excited by the antenna. The sensitivity of these parameters to load and capacitor layout variations is taken into account while satisfying a proper antenna frequency response. The sensitivity of the power spectrum to frequency variation is also investigated to allow the possibility of fast feedback of the power deposition into the core plasma of WEST. The high resilience of the TWA to these variations is demonstrated and the main parameters of the TWA expected in WEST are compared to a current WEST antenna for the same loading. Possible optimizations of the TWA antenna are discussed. The present study is fully transferable to a fusion reactor like DEMO or ARC.