Recent analysis of the ITER ion cyclotron antenna with the TOPICA code

Plasma heating in the Ion Cyclotron Range of Frequencies (ICRF) is adopted in most of the existing nuclear fusion experiments and is also one of the three auxiliary heating systems of ITER. Two identical ICRF antennas will be installed in ITER with the aim of delivering 10MW per antenna to the plasma for the baseline design configuration (upgradable to 20 MW/antenna). In order to optimize the feeding circuit and to evaluate and predict the overall performances of an ICRF launcher it is fundamental to perform radio-frequency simulations of the antenna detailed geometry loaded with a realistic plasma, and to extract the antenna input parameters, the electric current on conductors and the radiated field. In this work, we analyze the current ITER ICRF launcher, for the first time including the surrounding cavity between the port plug and the port extension, and a portion of the blanket tiles in the TOPICA code; the geometrical description of the antenna has reached an unprecedented level of accuracy. The ITER ICRF antennas have been the object of a comprehensive analysis, varying the working frequency, the plasma conditions and the poloidal and toroidal phasings between the feeding transmission lines. The performances of the antennas have been documented in terms of input parameters, power coupled to plasma and electric fields, for a reference set of ITER plasma equilibria and assuming a maximum voltage on the system.