Real-Time Data Processing Method for CO₂ Dispersion Interferometer on EAST

Abstract In this paper, a real-time data processing system is designed for the carbon dioxide dispersion interferometer (CO2-DI) on EAST to measure electron density and provide real-time feedback control. The system utilizes the parallel and pipelining capabilities of Field-Programmable Gate Array (FPGA) to digitize and process the intensity of signals from the detector. Finally, the real-time electron density signals are exported through a Digital-to-Analog Converter (DAC) module in the form of analog signals. The system has been successfully applied in the CO2-DI system to provide low-latency electron density data to the plasma control system on EAST. Experimental results of the latest campaign with long-pulse discharges on EAST (2022-2023) demonstrate that the system can respond effectively in the case of rapid density changes, which means it is reliable and accurate for future electron density calculation.