含地面反射效應之高空電磁脈波模擬

Abstract

本論文分析並模擬核爆產生之高空電磁脈波。首先依相關動態方程式計算初級及次級感應電流分佈，並代入Jefimenko 方程式以計算地面附近之入射電場，再根據地面介質頻域特性計算反射電場。數值模擬結果顯示高空電磁脈波包含一個脈衝和一個脈波，並可由理論推論其成因。模擬結果呈現反射場可能在某些情況下使脈衝時變率增加。

High-altitude electromagnetic pulses (HEMP’s) caused by a nuclear explosion is analyzed and simulated. The primary and the secondary electron currents induced by an explosion are calculated by solving relevant dynamic equations, involving the geomagnetic field. These currents in the deposition region are substituted into the Jefimenko’s equation to calculate the incident electric field near the ground, and the reflected fields are calculated considering the frequency-dependent properties of the ground medium. The characteristics of impulse and pulse are simulated and analyzed. By simulations, the reflected field may cause a faster change of impulse field in certain cases.