Skin Effect Analysis for Pulse Current in the PEA Based on Frequency Domain Method

Abstract

To study some of the mechanisms in passive electromagnetic armor (PEA), the pulse current skin effect and the action of the current along the length of a shaped charge jet as it passes through PEA are researched. Considering the different characteristic of the pulse current from the alternating current, a frequency domain analysis method of skin effect is introduced. With the background of PEA, time and frequency characteristics of the pulse current are analyzed based on the equivalent circuit model, and calculation method of the pulse current density distribution in shaped charge jet is obtained. Consequently, the skin depth during the discharge is researched. The validity of the method is approved by contrasting it with the Finite Element Method analysis results. Finally, a distribution of the specific action in the shaped charge jet elements is obtained based on the action time model. The results indicate that pulse current has a broadband, and its skin effect phenomenon is different from that of an alternating current. It shows that current density increases with the decrease in depth 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 4 km/s. While the action in the radial direction becomes larger, the element gets closer to the surface.