Development of TESPEL Configurations for Plasma Diagnostics

A Tracer-encapsulated Solid Pellet (TESPEL) injection method has been shown to be useful for many fields of plasma diagnostics. In order to provide more flexibility for such plasma diagnostics, we are developing various types of TESPELs. Here we report a new type TESPEL with a thin shell made of poly-dichlorostyrene useful for the impurity transport study. The new multilayer TESPEL configuration is also discussed. This type of TESPEL is not only useful for impurity transport study but also for the neutron observation due to the transient increase of the deuterium in the local position in the plasma for the upcoming LHD D-D experiment.