Design of real-time data acquisition system for interferometer-based electron density diagnostics on EAST

Area of Science:

• Plasma physics
• Fusion energy research
• Advanced diagnostics

Background:

• Electron density is a critical parameter for understanding plasma behavior in fusion devices.
• Laser-aided interferometers are standard tools for measuring electron density.
• The Experimental Advanced Superconducting Tokamak (EAST) utilizes multiple interferometer systems for electron density diagnostics.

Purpose of the Study:

• To develop and implement a high-precision, real-time data acquisition (DAQ) system for electron density measurements.
• To improve the accuracy and efficiency of data processing for laser-aided interferometers on EAST.
• To provide a reference data processing framework for future interferometer systems.

Main Methods:

• Implementation of a field-programmable gate array (FPGA) for real-time data processing.
• Utilization of fast Fourier transform (FFT)-based demodulation technology.
• Employing a high-precision analog-to-digital converter (ADC) for waveform digitization from Schottky mixers.

Main Results:

• Simulations demonstrate that the developed DAQ system meets the accuracy requirements for EAST interferometers.
• The system successfully processes multiple frequency signals from high-performance Schottky mixers.
• The FPGA-based system enables precise calculation of electron density values.

Conclusions:

• The developed real-time DAQ system is suitable for high-accuracy electron density measurements on EAST.
• The FFT-based demodulation and FPGA implementation provide a robust solution for interferometer data processing.
• The DAQ system's framework serves as a valuable reference for future laser-aided interferometer developments in fusion research.