A spark gap model for LTspice and similar circuit simulation software

Abstract

In the past, the simulation of pulsed power circuits used specifically designed programs such as Sandia's SCREAMER, NRL's BERTHA, or the industry developed TL Code. These codes incorporated specialized models for many pulsed power components which captured key manifestations of the physical phenomena. Now, the simulation of pulsed power circuits is likely to be accomplished with the ubiquitous SPICE-based software. Of the available software, LTspice, a program developed by semiconductor manufacturer Linear Technology Corp, has become very prevalent due to its ease of use, continuous improvement, and free availability. However, LTspice — like all SPICE programs — does not include realistic models for key pulsed power circuit devices — including the spark gap switch. While simple switch models do exist in LTspice and other SPICE programs, these can only crudely approximate the behavior of a spark gap. This effort focuses on developing an LTspice circuit model for a gas-filled spark gap switch that is physically realistic while being simple enough as to permit simulations to run in reasonable times on typical personal computers. Efforts are made to create a model that is portable between different SPICE programs with minimal modification.