Development of railgun pellet injector using a laser-induced plasma armature

The application of the electromagnetic railgun system for pellet injection into fusion plasmas is one of the most feasible technologies for accelerating a brittle, solid hydrogen-isotope pellet to a high speed (up to 5 km/sec or over) without a sabot (protector of the pellet). In our system, the plasma armature is induced optically by an intense laser beam and accelerated by the electromagnetic force in the railgun. The plasma armature then accelerates the pellet to high velocity. A series of experiments using dummy (plastic and wooden) pellets (10-33 mg) has been conducted to examine the system. In addition, the hydrogen pellet acceleration tests have been initiated. The current experimental results indicate that the railgun system can be one of the optimal methods to provide higher speed pellets for fusion plasmas