Semi-Analytical model of Ion Cyclotron Resonance Heating antenna-plasma coupling and wave propagation in hot magnetized plasma

A simple model of coupling an electromagnetic wave in the Ion Cyclotron (IC) frequency domain with a plasma in tokamak configuration is presented and solved in a simplified Cartesian geometry. The electromagnetic field radiated by the antenna is accurately described by the CST Studio Suite ® that shows the electromagnetic field radiated by the antenna but does not consider the load due to the plasma just in front of the antenna itself. The Ion Cyclotron Resonance Heating (ICRH) antenna consists of several metallic straps (accommodated in a tokamak port), on which a current flows that varies sinusoidally with time. The spectrum of the electromagnetic field radiated by the antenna acts as boundary condition for the solution of the wave equation inside the plasma. A simplified equation for the IC mode inside the plasma is derived and solved in straight Cartesian geometry by considering a simplified model of the space variation of the plasma density, temperature and magnetic field profiles. In deriving the simplified wave equation, a complex dielectric tensor has been considered by separating the Hermitian (essentially given in the cold plasma approximation) from anti-Hermitian part (temperature effects and wave absorption). This model results are relevant for the Divertor Tokamak Test facility (DTT), a new tokamak device under construction at ENEA research center in Frascati (Italy). DTT will be equipped with an ICRH system, whose construction is ongoing.