Linear railguns consist of two flat plate electrodes separated by insulating spacers and accelerate sheet armatures.
Additionally, a complex triple joint seal may exist at the breech of the bore, which can often pose an extreme engineering challenge.
This is an instability in which the magnetic pressure front can out-run or "blow-by" the plasma armature due to the radial dependence of acceleration current density, drastically reducing device efficiency.
Controlled jets from plasma rail guns can have peak densities in the 1013 to 1016 particles/m3 range, and velocities from 5 to 200 km/s, depending on device design configuration and operating parameters, and the upper limits may be higher.
[citation needed] Plasma rail guns are being evaluated for applications in magnetic confinement fusion for disruption mitigation and tokamak refueling.