Preliminary results of drift instability by fast optical images in KT-5D toroidal plasma

Drift instability in plasma generated by electron cyclotron resonance (ECR) in KT-5D device was investigated by using a fast camera and Langmuir probes. The similarity between the distribution of light intensity from the images and the plasma pressure indicates a nearly linear relationship. The discharge images taken by the camera and the plasma parameters measured by the probes also indicate the existence of low frequency turbulent events with a time scale less than a few mini-seconds.