Research on the real-time signal conditioning method for dispersion interferometer in HL-2M

A new CO₂ laser dispersion interferometer has been developed in the HL-2M tokamak to measure the electron density. In order to meet the needs of high-precision measurement, a data acquisition system with real-time signal conditioning (RSC) method is proposed. It can eliminate part of the impacts of environmental factors, such as mechanical vibration, light path changes, and plasma refraction effect during experiments. In harsh environments, the system can measure the line-integrated density with a high precision of 2 × 10¹⁸ m⁻² with the RSC method. The system has been tested in a recent HL-2A experimental campaign, and the results show that the RSC method plays an important role in the plasma electron density measurement.