A fully electromagnetic hybrid PIC-fluid model for predictive fusion neutron yield in dense plasma focus

Abstract A fully electromagnetic hybrid ion-PIC/electron-fluid framework is developed for the implosion-to-pinch phase of dense plasma focus (DPF) discharges. Ions are advanced kinetically, electrons form a charge-neutralizing fluid under the quasi-neutral approximation, and the full Maxwell equations are solved in both plasma and vacuum. The generalized Ohm law includes resistive, electron pressure-gradient, and Hall terms. Applied to a non-hollow 180 kA geometry initialized from a pre-ionized end-of-rundown state, the framework reproduces the axial rundown, radial compression, and pinch stages. The sheath front trajectory agrees with fully kinetic benchmarks within 10%, and a pinch-radius comparison captures the radial collapse. A beam-target neutron diagnostic applied to the simulated ion distribution gives a yield of 0.296e7, at the same scale as the fully kinetic reference. The ion spectrum develops a non-Maxwellian suprathermal tail to about 0.25 MeV. The yield remains sensitive to the electron-temperature closure and anode geometry. The framework captures relevant macroscopic observables and ion-kinetic diagnostics at a computational cost roughly 1e5-1e6 times lower than comparable fully kinetic electromagnetic PIC simulations.