EMPPIC: A PIC Code for Nuclear Electromagnetic Pulse

Abstract

The nuclear electromagnetic pulse (NEMP) is a pulsed electromagnetic wave generated by the prompt gamma emitted from a nuclear explosion. In the 1970s, Longley and Longmire proposed a simulation method for the NEMP, which has been widely used in the NEMP simulation such as the widely used code CHAP. Constrained by the computational capabilities of the time, the CHAP program relied on numerous assumptions, which have been scrutinized in recent years. In addition to the CHAP method, in 2016, Friedman et al. proposed the idea of constructing a NEMP program based on the Particle-in-Cell (PIC) method. The PIC method not only accurately simulates the dynamics of electrons but also self-consistently simulates the influence of pulsed electromagnetic fields on electrons, and requires fewer assumptions. Unfortunately, due to the excessively computational consuming of the PIC method, Friedman et al. couldn't simulate the full-scale NEMP spanning tens of kilometers. In this paper, we present the first full-scale simulation program for the NEMP based on the PIC-fluid coupling method. By utilizing the moving window method, double-grid methods and linked list storage techniques, we significantly reduce the computational consuming. Additionally, a mixed scattering collision method is used to efficiently simulate elastic collisions between Compton electrons and atmospheric molecules. Detailed discussions of the relevant simulation results are also provided.