Effects of cold neutral gases on the high density plasma

Summary form only given, as follows. In order to simulate the radiation cooling effect at tokamak edge plasma, we construct a plasma-material interaction chamber installed various plasma sources such as filament, LaB/sub 6/ (DC), ICP, and helicon plasma, whose diameter is 20cm and length is 150cm. To measure the plasma density, potential, electron and ion temperature variation during the gas injection, a scanning hybrid probe consisting of electric and optical probes is developed. This hybrid probe will be installed at the ´Hanbit´ device to monitor the normal mirror plasma and to study the radiation cooling effect during the simulated divertor experiment.