Implications of rail electrodynamics

Summary form only given, as follows. A model was developed to investigate possible effects of rail electrodynamics on the performance of railguns. This model describes the oscillatory nature of the rail motion in response to the Lorentz force and the compressive restoration force of material which is behind the rails. In this model, the rails are found to oscillate with a frequency of β. The rail dynamic behaviour induces local electric fields. The effect of these electric fields on stationary particles (lab frame) and on particles moving at the velocity of the plasma/projectile system (projectile frame) was investigated. In the lab frame, rail dynamics induce local electric fields which have maxima periodically spaced behind the projectile at locations where βt_P is an odd multiple of π where t_p is the time since the projectile has passed a location of the rails. Consequently, if restrike occurs, it is likely to occur at locations where βt_P is an odd multiple of π. When the projectile is accelerating, rail dynamics induce electric fields in the projectile frame which have maxima where βt_P is an even multiple of π. As the projectile velocity increases, the locations of the peak voltages move farther behind the projectile, which can enhance armature separation. For the CHECMATE railgun, calculations indicate that the rail displacement in on the order of 2 mm, the rail velocity is on the order of 50 m/s, and the voltages induced in the projectile frame are on the order of 20-40 V