Overview of recent progress for high power and long pulse operation of ICRF heating system in EAST Tokamak

Significant advancements have been achieved in facilitating high-power and long-pulse operation up to 310 seconds 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 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 seconds and maintained 1.2 MW for 310 seconds.