On the Self-Consistent Simulation of High-Altitude Electromagnetic Pulse

Self-consistency between Compton electrons and electromagnetic (EM) fields is an important physical mechanism in the generation and propagation of early-time high-altitude EM pulse (HEMP). This article develops an iterative self-consistent HEMP simulation scheme based on high-frequency approximation (HFA) algorithms. The self-consistent effect between electrons and fields is decoupled and neglected in the first iteration and then is taken into account by considering the results of the field as the independent fields, which affect electrons in the next iteration. The computation can be improved up to tens of times faster than the existing non-iterative method. This article provides a detailed study about self-consistent HEMP with regard to the influence of prompt gamma yield and various prompt gamma ray spectra. The saturation phenomenon caused by secondary electrons is considered as well. The self-consistent effect is significant in the source region. At ground level, it shortens the duration and reduces the amplitude of HEMP. Numerical results showed that the differences caused by self-consistency are significant in the simulation with different prompt gamma yields and prompt gamma ray of monoenergetic and spectrum.