A novel method to simulate the high-altitude nuclear electromagnetic pulse under the asymmetrical situation

The zero-order integral equation method (IEM) and the second-order IEM were introduced to simulate the high-altitude electromagnetic pulse (HEMP) in our former reports, where the planar gamma radiation model and the point gamma radiation model were utilized, respectively. Herein, the equation of the IEM is analyzed and simplified, after which the fifth-order method is introduced. Several asymmetric gamma radiation patterns are employed to simulate the asymmetric environments. The results show that the fifth-order method can well describe the tendency of the variation of the electric current source in the deposition region and that the HEMP radiating onto the ground not only depends on the electric current source along the line of sight (LOS) but also depends on the distribution of the electric current source around the LOS.