Three-dimensional simulations of RF wave propagation and power coupling in cold magnetized plasma near an ICRF antenna

The electromagnetic wave propagations and their coupling characteristics in magnetized plasma near the antenna of ion cyclotron range of frequencies (ICRF) is studied based on self-developed 3DFEM-IA code. This code effectively resolves the three-dimensional (3D) geometry and the electromagnetic field using the finite element method. Our findings reveal that the distributions of electromagnetic fields and energy flow density significantly depend on the antenna phases, surface current density on the antenna straps, and background plasma density. Notably, the non-uniform surface current density on the antenna straps, resulting from the presence of induced currents, contributes to a reduction in coupling power within the edge plasma. Furthermore, the calculated coupling impedance increases with plasma density, corroborating well with experimental measurements.