A wide-viewing-angle visible light imaging system （VLIS） was mounted on the Joint Texas Experimental Tokamak （J-TEXT） to monitor the discharge process. It is proposed that by using the film data recorded the plasma vertical displacement can be estimated. In this paper installation and operation of the VLIS are presented in detailed. The estimated result is further compared with that measured by using an array of magnetic pickup coils. Their consistency verifies that the estimation of the plasma vertical displacement in J-TEXT by using the imaging data is promising.
To improve the understanding of the turbulence intermittency, a detailed investigation of the intermittency of the density fluctuations has been performed in the boundary of J-TEXT. The intermittency of the density fluctuations and its influence on the radial transport are reported. The probability distribution functions of the density fluctuations are not scale-invariant, being inconsistent with the self-organized criticality hypothesis. The underlying dynamics of the intermittency are detected using the quiet-time statistical method. The probability distribution function of the quiet times shows double-power-law regions, indicating the existence of correlations between the successive burst events.
Joint-TEXT （J-TEXT） is a medium-sized tokamak constructed at Huazhong University of Science and Technology. At present, the poloidal field power supply consists of three subsystem sets, namely Ohmic heating field power supply, vertical field power supply, and horizontal field power supply. The structure and function of the poloidal field （PF） power supply as well as the updated control system of the power supply is described. The new scheme uses the realtime feedback control method for the poloidal field power supply. The experimental results show that the poloidal field energized by poloidal field power supply meets the J-TEXT operational requirement perfectly.
