A simple and decoupled beam stability control method for gyrotron long pulse operation

• A decoupled beam stability control method for gyrotron long-pulse operation. • Dynamically regulate filament power via PI control to stabilize beam current. • Modular design decouples DAQ, feedback, and beam control for robustness. • Enhance output power stability in ECRH systems without pre-installed feedback. Gyrotrons are widely used in ECRH (Electron Cyclotron Resonance Heating) systems for plasma heating in nuclear fusion experimental devices. Due to the radiation cooling effect of the gyrotron electron gun, the beam current gradually decreases during long-pulse operation, leading to unstable output power. This paper presents a long-pulse gyrotron beam current control method that regulates the beam current by adjusting the filament power supply, thereby stabilizing the gyrotron output power. The method comprises three decoupled modules: data acquisition, feedback control, and filament power control. Data acquisition is implemented via PXI, feedback control adopts a PI (Proportional-Integral) algorithm, and filament power control is realized through SCPI (Standard Commands for Programmable Instruments) over Ethernet. This approach enhances output power stability and is particularly suitable for ECRH systems without pre-installed beam current feedback mechanisms.