Bench test of phase measurement on dispersion interferometer for EAST.

Abstract

In recent years, different traditional interferometers have been the necessary diagnostic of electronic density measurement on fusion devices. Until now, two main problems always influence the density measurement: the mechanical vibration and fringe jump in the calculation. The dispersion interferometer (DI) with a long-wavelength infrared wavelength is a good choice because mechanical vibrations can be canceled and the fringe jump can be inhibited. This paper describes the bench test of phase measurement using a wedge instead of plasma on the DI. The results show good agreement with the theoretical calculations. In the background measurement, this DI without a vibration isolation system has good performance, and the drift of the baseline is less than 2 × 1017 m-2 in 3 s and less than 5 × 1017 m-2 in 400 s. Plasma data will be obtained during the next campaign on EAST (Experimental and Advanced Superconducting Tokamak).