关键词: HCN波导激光器, 多道干涉仪, 电子密度分布

Abstract:

To measure the electron density profile, a new system of the multi-channel FIR laser interferometer has been designed and set up on HL-2A tokamak (with divertor configuration). A series of dielectric wave-guides are employed in the arrangement of long distance optic path and a high power HCN laser with six-meter cavity has been developed, in addition, the lock-in loop filter with FPGA technology has been adopted to reduce the disturb effect. The phase-comparison methods of software and hardware are simultaneously used to monitor the electron density and to display the density evolution timely. The accuracy of the multi-channel interferometer is closed to 1/33 fringe, the corresponding density is 1.3×10¹¹cm^-3, and the time resolution is 0.1ms.

Key words: HCN wave-guide laser, Multi-channel interferometer, Density profile