Hydrogen pellet injector for plasma fueling experiment

At present, one of the most promising methods of plasma refueling in plasma fusion devices is frozen pellet injection. This method has some advantages. That is, by choosing the pellet size and velocity in an appropriate way, 1) It is easy to deposit the particles into the plasma center. 2) It is easy to control the plasma density profile to an optimal one. 3) Consequently, it is possible to improve plasma confinement characteristics. Therefore, frozen pellet injection has been adopted for many plasma fueling applications. Recently, a pneumatic multiple pellet injector has been developed by Kobe Steel Ltd. in collaboration with Kyoto University and installed on HELIOTRON-E for advanced pellet injection experiments. In this paper, we will present the configuration of the injection and basic performance. (author)