Preliminary experimental results of encapsuled pellet injection on the HL-2A tokamak

Preliminary experiments of encapsuled pellet injection are carried out on the HL-2A device. Basic construction of the encapsuled pellet and manufacture technology are introduced. The encapsuled pellet is with the diameter ∼ 0.76 mm, thickness of polystyrene shell ∼20μm and internal deuterium pressure ∼1.5 MPa. Experimental results show that the encapsuled pellet is intact during its flight path, and can be injected to the depth of ∼12 cm with the velocity of 200 m·s^-1. The fuelling efficiency is about 60%. (authors)