3D EM modeling of large-scale pulsed power accelerator systems

We are developing an electromagnetic (EM) wave simulation technique for full-system modeling of large-scale, pulsed-power accelerators driving z-pinch loads. The simulations utilize the time-domain, finite-difference EM particle-in-cell methodology. These large-scale numerical simulations use a multiple-region, domain-decomposition approach to treat the time-dependent generation and evolution of EM waves in vacuum and other media in wave guide structures, including transmission lines, geometrically complex post-hole convolutes, and impedance and current transformers. Individual components of the systems are already being used to provide time-accurate models of power delivery within a single numerical calculation. Combining these individual simulations enables comprehensive modeling of power delivery in full pulsed power systems and should prove to be an important pulsed power design tool. As an example, we present a case study for the design of a next generation PW-class z-pinch driver, ZX. We examine the case for a ZX accelerator design based on LTD technology driving impedance transformers. Individual transmission lines are coupled to the z-pinch load through a triple post-hole convolute and the load is modeled as a dynamic imploding liner.