Repeating pneumatic pipe-gun for plasma fueling

A pellet injector of the repeating pneumatic pipe-gun type has been designed for plasma fueling applications. Its use reduces the time for pellet formation by an in situ technique from 2 to 3 min to 2-10 s. The basic idea of the proposed approach to pellet formation is to melt prefrozen solid fuel and to admit it through a porous unit into a barrel for refreezing. The injector provides for a continuous injection of an unlimited number of pellets. Over 250 hydrogen and deuterium pellets of 3 mm diameter and 3-10 mm in length were accelerated to 1.2 km/s at a rate of 1 pellet per 10-34 a by manually controlled injector operation. An automatically controlled multishot pellet injector (>10 barrels) is capable of providing a continuous and reliable fueling of large fusion devices such as the large helical device and the International Thermonuclear Experimental Reactor (ITER). (C) 1997 American Institute of Physics.