Advances and Prospects of ECRH System on EAST

The Experimental Advanced Superconducting Tokamak (EAST) electron cyclotron resonance heating (ECRH) is an important auxiliary heating method, helping EAST achieve 1056 s of super I-mode discharge. There are currently four subsystems with six gyrotrons on EAST. At present, the EAST ECRH system can stably output 3.2-MW radio frequency (RF) power at 140 GHz with long pulses above 100 s (up to 1000 s) and can output 1.3-MW RF power at 105 GHz with long pulses above 100 s. Using ECRH as one of the main heating methods, EAST has made a series of experimental progress in recent years. In April 2023, the steady-state H mode plasma of 403 s was obtained. In the next two years, we plan to develop #5 and #6 systems. After the development, the total RF power can reach 5 MW at 140 GHz. In this article, the composition and operation of the EAST ECRH system were introduced, and the development advances of gyrotrons, transmission lines (TLs), and antennas were discussed. We analyzed the key characteristics related to the long-term operation instability of gyrotrons, which is an important reference for the operation of future gyrotrons.