Experimental study on effect of the toroidal magnetic field ripple on the ECR layer in TABAN tokamak

摘要

The study of ECR assisted breakdown on TABAN tokamak (B-T = 7000 G, R = 45 cm, a = 15 cm) has been directed to find the best conditions for ECR pre-ionization and plasma generation. The toroidal magnetic field ripple (8) was investigated to obtain optimum pressure at pre-ionization phase. The internal chamber can be divided into two areas considering the 8 value: underneath and between the coils.The toroidal magnetic field ripple was used to determine the moment of the Electron Cyclotron Resonance (ECR) layer entrance into the chamber, and consequently, calculate the accurate breakdown time and then optimum pressure range (3 x 10(-2) Pa similar to 5 x 10(-2)Pa) was obtained at pre-ionization phase. In addition, the toroidal magnetic field and its ripple have been experimentally measured using magnetic probes and simulated by COMSOL software as well.