Unique diagnostic developments with tracer-encapsulated pellet injection

Summary form only given, as follows. Unique diagnostic method has been developed with using tracer-encapsulated pellet (TESPEL) injection. TESPEL; consists of polystyrene as an outer shell and of specific material as a tracer. The amount of the trace varies from on ball with diameter of 100 /spl mu/m to 8 balls with the same diameter each. The special features of TESPEL injection into the plasma are(a) local deposition inside the plasma, (b) the deposited amount of the tracer in the plasma can be known precisely, (c) relatively wide selection of tracer material is possible. The achievements of TESPEL experiments on LHD are: impurity transport properties such as diffusion coefficient inward pinch velocity were obtained for the various conditions of the plasma.