Research and Developments of Advanced Pellet Injector

点击翻译按钮获取中文摘要

A pellet injector of repetitive pneumatic pipe-gun type has been designed for advanced plasma fueling applications. This new concept is estimated to be able to reduce the time for pellet formation by an in situ technique from 3-5 minutes to 2-10 seconds. The basic idea of the new approach to pellet formation is to supply a hydrogen isotope pellet through a copper porous unit into a pipe-gun-type barrel. Two modes are possible : (1) to push liquid hydrogen isotope through a porous unit and re-freezing inside of the barrel, (2) to push solid hydrogen isotope through porous unit to the inside of the barrel. This principle provides a continuous injection of an unlimited amount of pellets. For demonstration of the proof-of-principle, several experiments have been carried out. Hydrogen pellets of 3 mm in diameter and 3 to 10 mm in length were accelerated to 1.2 km/s at rate of pellet per 10-34 s with a manually controlled injector operation. On the basis of this experience, we succeeded in 3 to 4 seconds repetition with high reliability.