RF, disruption and thermal analyses of EAST antennas

CAS IPP and MIT PSFC are collaborating on Experimental Advanced Superconducting Tokamak (EAST), the first tokamak with superconducting toroidal and poloidal magnets and a testbed for technologies proposed for the ITER project. Presented in this paper are RF, disruption and thermal analyses of EAST antennas. All were performed by COMSOL commercial software package Version 5. Analyzed are the I port 4 strap and B port 2 × 2 strap antennas, which are currently installed on EAST. RF analysis over the Ion Cyclotron Range of Frequencies (ICRF) gets insight into the coupling mechanism to optimize antenna plasma coupling. A lossy dielectric model was created which loads the antenna. The Scattering parameters (Sparameter) were extracted. Peak electric field parallel to the magnetic field of the straps, coaxes and other components were determined. Parametric analysis of the operation frequencies on the electric field are also performed. Disruption analysis addresses the impact of the magnetic field and plasma. Temporal currents of poloidal field and plasma as well as the spatial toroidal field were imported into the electromagnetic (EM) model. The structural analysis afterwards determined the stress due to antenna loads generated during the disruption. The loads resulted from the reaction of circulating eddy currents in the antennas with the toroidal and poloidal magnetic fields. Thermal analysis, a fluid - heat transfer - structural multiphysics analysis, performed for the strap and Faraday rod by applying heat loads from the plasma, ripple trapped particles and RF heating for steady state, are also presented. Finally, benefits of a future field-aligned 4 strap antenna were discussed.