Image processing system for plasma position control on TRIAM-1M

In TRIAM-1M, at the time of the long hour discharge of plasma, the hot spots of concentrating thermal load occur frequently on the limiter, and the brightness of those hot spots increases gradually, and these are observed by photographing the poloidal limiter with a CCD camera. The concentration of thermal load to one place must be avoided. In this study, the image processing system which detects the positions of hot spots by processing the plasma section images photographed with a CCD camera, and controls the position of plasma to the direction of reducing thermal load, was developed. As the prior stage of applying it to plasma discharge, the simulation experiment of changing the brightness and position of the light source simulating a hot spot was carried out, and the reliability of the image processing system developed this time was confirmed. The control of plasma position is one of the problems of the steady operation of tokamak. The new system of measuring plasma position using Hall element, which can measure directly magnetic field, was developed. The feedback control system for plasma position control in TRIAM-1M and the image processing system are described. The simulation experiment method and the results of the output from the image processing system in relation to the changes of brightness and position are reported. (K.I.)