Diagnosis of the periodic vibration using laser interferometry

Abstract

Temporal phase-shifting interferometry (TPSI) has been proposed for morphology monitoring of Plasma-Facing materials (PFMs) in Tokamak due to its high precision and far-field online capability. However, this monitoring method is sensitive to vibrational environment and the mechanical vibration in Tokamak, such as the Experimental Advanced Superconducting Tokamak (EAST), would lead to a decrease in the accuracy of the measurement or even wrong results.Real-time detection of the vibration parameters of the Tokamak during the plasma operation to compensate for the error of the TPSI measurement is a solution to improve the accuracy. In this paper, a laser interferometry platform for diagnosing and measuring vibration amplitude and frequency adopting the fringe-counting (FC) method has been introduced. We measured the different vibration amplitudes and frequencies using the proposed approach. The results show that the method has a potential application for in-situ measurement of surface morphology of PFMs in Tokamak like EAST.