Field-Circuit Coupled Simulation With an Equivalent Circuit Model for High-Voltage Spark Gaps

This study addresses the complexities of designing and implementing high-performance, high-voltage (HV) switches for large-scale, high-energy-density physics (HEDP) research facilities. While spark gap switches are a conventional choice in pulsed power systems such as Marx generators and linear transformer drivers (LTDs), meeting criteria such as low jitter, a low prefire rate, low inductance, and low cost remain challenging. This article emphasizes that HV spark gap switches in a large system can interact electrically, leading to operational issues such as prefire, delayed-fire, or no-fire events. To mitigate these challenges, this study aims to develop a modeling and simulation (M&S) workflow that is extendable to a multiswitch system, focusing on a 3-D electromagnetic field interacting with spark gap switches. Drawing inspiration from previous work that employed the SPICE algorithm for spark gap modeling, this article introduces a dynamic model for pulsed breakdown (BD) in spark gaps using nonlinear circuit elements. A novel algorithm based on the energy absorbed by the streamer channel is proposed for the accurate prediction of BD delay. The commercial software CST Studio Suite is employed for 3-D field-circuit coupled simulations. This study also outlines the implementation of SPICE elements in CST and validates the model using a simple capacitor discharge circuit.