Measure variation of magnetic field waveforms above the rails of rail-gun during the launching period

The rail-gun has two rails with an armature sliding along the rails, and the armature is accelerated by the transient current. In order to analysis variation of magnetic field waveforms above rails of the rail-gun during the launching period for EMI designs, the magnetic fields are measured by loop probes, and current waveforms are measured by calibrated probes. The magnetic fields waveform besides static rails has the same raise time and width time as the main current. According to the armature movement states and measurement positions, magnetic waveforms are distinguished with each other. The experiment results show that magnetic field waveforms above the rails change for the different positions. There are narrower raise time and last time with higher velocities. The truncated waveforms introduce new spectrum signals around the rails. The waveforms at different positions are compared with each other, which can inflect the magnetic field distribution along the rails during the armature is launching. The results are useful to analysis the interference of the transient environment for the rail launcher and it is also useful for the EMI design of rail-gun systems.