Soft X-ray imaging diagnostic system on the J-TEXT tokamak

A soft X-ray (SXR) imaging system composed of three miniature SXR pinhole array camera designed and installed on the joint texas experimental tokamak (J-TEXT) for the study of plasma equilibrium and fluctuation properties during ohmic discharges. The imaging system functions well, giving good resolution and maneuverability. Combined with the use of the biorthogonal decomposition technique, it helps us to analyze the sawtooth crashes and their basic parameters such as reversal surface and modes. Furthermore, the plasma displacement is measured using SXR emission and the results are compared with those from magnetic diagnostic tools. The comparisons verify that the SXR imaging system is a legitimate alternative for non-magnetic plasma offset observation. In addition, it can form the basis of a real-time feedback control system for magnetic-confined plasma.