A Fully Electromagnetic Hybrid PIC-Fluid Model for Predictive Fusion Neutron Yield in Dense Plasma Focus
While magnetic confinement fusion (MCF) and inertial confinement fusion (ICF) remain the primary routes toward controlled fusion, progress is still constrained by energy loss, plasma instabilities, and the cost and complexity of large-scale facilities. The Dense Plasma Focus (DPF) device presents a compact, pulsed-power-driven alternative for producing fusion-relevant conditions and neutron emissions. However, the quantitative prediction of neutron yield in DPF devices poses a significant numerical challenge, primarily due to the imperative of self-consistently resolving kinetic ion behavior, electromagnetic energy coupling, and vacuum field evolution. This complexity often impedes a definitive understanding of the underlying neutron production mechanisms. To address this, we develop a fully electromagnetic hybrid simulation framework: ions are advanced kinetically with particle-in-cell, electrons are a quasi-neutral fluid, and Maxwell's equations are solved in both plasma and vacuum. The generalized Ohm law includes resistive, electron pressure-gradient, and Hall terms, with a predictor-corrector update for current density. We apply the model to a non-hollow 180 kA DPF geometry similar to the LLNL configuration. The simulated ion density, ion temperature, and axial electric field reproduce sheath formation, axial rundown, radial compression, and post-pinch expansion. The outer sheath front position agrees with fully kinetic benchmarks within 10\% over the available comparison interval. With a compact fit to the D-D fusion cross section, the predicted total neutron yield is 0.296e7, comparable in order of magnitude to reported fully kinetic results at similar currents and nearly two orders of magnitude higher than earlier hybrid results.