A device has been constructed to study the behavior of high-current, high-velocity plasma arcs, similar to those present in plasma-driven electromagnetic launchers. An electromagnetic launcher plasma armature is a magnetically driven arc with a current of several hundred kiloamps and a velocity of a few km/s. The device described in this paper is designed to produce such a plasma, with a peak current of 300 kA and a variable linear velocity. The current is produced by pulse-forming networks (PFN’s) placed at each end of the device, and the arc velocity is varied by adjusting the currents delivered to the arc from each PFN. The device is used to study the behavior of the moving arc and to develop diagnostic techniques that may be applied to such systems.