Assessment of SGEMP Responses in Gapped Multi-Core Shielded Cables Using FDTD and Monte-Carlo Method

X-ray illumination on shielded cables induces large currents in their core conductors, a phenomenon known as cable System Generated Electromagnetic Pulse (SGEMP) effects. These large currents potentially disrupt the normal operation of electronics connected to these cables. In this study, we present a numerical method integrating FDTD and Monte-Carlo techniques to evaluate SGEMP responses in multi-core shielded cables with gaps. Initially, the problem is modeled as a network of multi-conductor transmission lines with distributed parameters and distributed current sources. These sources are excited by deposited charges generated through X-ray interaction with shielded cable materials. The charge distribution across the cable cross-section is calculated using the Monte Carlo method, determining the distributed current sources. Subsequentially, the SGEMP responses at the core conductor terminals is computed using the Finite Difference Time Domain (FDTD) method. The approach proposed is then applied to analyze the SGEMP responses of a seven-core shielded cable with vacuum gaps, and the impact of gaps on the terminal responses. The study would guide the radiation hardening design for satellite cables, enhancing their reliability in space environments.