Quasi-optical electron cyclotron emission imaging diagnostic advancements on the J-TEXT tokamak

The new quasi-optical electron cyclotron emission imaging (ECEI) diagnostic system on the J-TEXT tokamak has been developed and characterized. The quasi-optical system consists of two subsystems: the major imaging optics system for plasma imaging and the local oscillator (LO) optics system to drive the mixers in the antenna array. For the updated demands, some modifications and adaptations are accomplished on the major imaging optics. The vertical zoom ratio, focus capability, and field curvature have been measured on the J-TEXT facility, with good matching with the simulation results. For the various experimental requirements on J-TEXT, the remote control system is adopted for the major imaging optics. As for LO optics systems, spherical LO optics and hyperbolic LO optics have demonstrated high performance. Uniform power deposition has been optimized to drive all mixers and minimize insertion loss.