A frequency domain method for the pulse current skin effect in the passive electromagnetic armor

Abstract

To confirm the action mechanism of the passive electromagnetic armor (PEA), the pulse current skin effect in the PEA are researched. Considering the different characteristic of pulse current from the time-harmonic current, a frequency-domain analysis method of skin effect is introduced. With the background of PEA, time and frequency characteristics of pulse current are analyzed based on the equivalent circuit model, and calculation method of pulse current density distribution in SCJ is obtained. Consequently the change rule of the skin depth during the discharging is researched. The validity of the analysis method is approved by contrasting with the FEM analysis results. Finally, distribution of the specific action in the shaped charge jet elements is obtained based on action time model. The results indicate that, pulse current is broadband distribution, and its skin effect phenomena is different from unifrequent time-harmonic current. It shows that current density increases with depth decreases not all the time, but declines on the surface of the conductor at the trailing edge of the pulse current. And the specific action is concentrated on the tail of the jet whose velocity is less than 4km/s. While the action in the radius direction becomes larger as the element closer to the surface