Pellet acceleration study with a railgun for magnetic fusion reactor refueling

Design, construction, and preliminary testing of a two-stage pellet injection system capable of achieving hydrogen pellet velocities of 5–10 km/s are described. The system, which is intended for the refueling of magnetic fusion devices, combines a gas gun with a small-bore, plasma-arc-driven electromagnetic railgun. The gas gun uses hydrogen gas as the propellant and injects a medium-velocity pellet into the railgun. Once inside the railgun, the propellant gas following the pellet is electrically broken down forming a plasma arc armature. The propulsive force of this plasma arc armature further accelerates the pellet to higher velocities.