Study of an Ellipsoidal Mirror for the ECRH Antenna System on EAST

Electron Cyclotron Resonance Heating (ECRH) is the key auxiliary heating system in Experimental Advanced Superconducting Tokamak (EAST). The function of the ECRH antenna is to inject the high RF power into plasma resonance layer for heating, electron cyclotron current drive (ECCD), stabilization of magneto hydrodynamics (MHD) modes and other physics applications. The focusing mirrors of the antenna are very important to achieve the fine localized power deposition. In order to further improve the ability of Gauss beam focusing in the antenna, a new ellipsoidal reflector is studied to replace the spherical focusing mirror in this paper.