Measurement of the mechanical vibration and its impact on the magnetic diagnostics in the J-TEXT tokamak

The mechanical vibration and its profound impacts on the magnetic diagnostic measurement have been observed on the J-TEXT tokamak. To explain the low frequency magnetic oscillation induced by the vibration, an analytical model has been developed. The comparisons between the experimental results and the analytical model indicate that the vibration of the vacuum vessel is along two keystones of J-TEXT. Through vibration measurements of J-TEXT components, we have identified that the origin of vibration is the rapid change of the pre-magnetization field. Additionally, it is found that the relative vibrations between magnetic diagnostics and toroidal magnetic fields contribute to the low frequency magnetic oscillation. The results obtained in this work are not only important for the prediction of vibration in fusion devices, but also helpful for experimenters to input corrections in obtained diagnostic results.