Electromagnetic field measurements near a railgun

Electromagnetic (EM) field measurements were conducted near a 15 mm square-bore railgun accelerating a metal armature. Under shorted rail conditions, the EM environment is quasi-static and directly related to the rail current distribution. Under operational conditions the EM environment is more complex and can include nonlinear effects such as muzzle arcing. Electric and magnetic field measurements were designed to characterize the transient EM environment external to a capacitor-based railgun. Selected data are presented to demonstrate the time history and the spatial variation of the measured EM environment. Analytical results, assuming a quasi-static armature acceleration, are included for comparison. Good agreement in amplitude, waveform, and spatial variation is obtained with a filament current model.<>