Significant advancements have been achieved in facilitating high-power and long-pulse operation up to 310 s by developing novel techniques for ion cyclotron range of frequency (ICRF) wave heating systems on EAST. This paper presents an overview of the current status of the ICRF facility, spotlighting the principal modifications implemented on the original installation and the corresponding results. A new ICRF antenna has been devised, featuring an increased toroidal distance between the straps. This design reduces the parallel wave number, augments wave coupling efficiency, and boosts plasma heating performance. A novel active water-cooling mechanism for the Faraday screen (FS) has been introduced to ensure the FS temperature remains within a safe range during long-pulse and high-power operations. An impedance transformer has also been developed to diminish the voltage in the transmission line. A load-tolerant matching network with a conjugate-T configuration guarantees stable operation by maintaining low reflection across a broad spectrum of antenna loads. Moreover, a rapid and real-time impedance matching methodology has been successfully incorporated, empowering the system to adapt the matching system to the fluctuating antenna load dynamically. Thanks to these optimizations and upgrades, during the EAST experiments, we attained 2.2 MW of ICRF power for 2 s and maintained 1.2 MW for 310 s.
This paper describes advancements in the ion cyclotron range of frequency (ICRF) heating system on the EAST tokamak, enabling high-power and long-pulse operation. Key improvements include a new ICRF antenna design, active cooling for the Faraday screen, and a load-tolerant matching network with real-time impedance adjustment.