Optimizing Dense Plasma Focus Neutron Yields via Kinetic Simulations

We report on a study using the particle-in-cell code Chicago(C. Thoma, Phys. Plasmas 24, 062707 (2017)) to perform fully kinetic simulations of dense plasma focus (DPF) with a variety of anode and target configurations. The evolution of a DPF is broken into several phases. The first phase involves a plasma sheath being formed from the electrical breakdown of fill gas along the insulator. JxB forces then accelerate this plasma along the anode and then inwards towards the axis. The final phase occurs when the plasma implodes on axis and pinches to high density and temperature. During this final phase DPFs can accelerate MeV ion beams and the interaction of these beams and the target formed can produce neutrons. In order to optimize the neutron yield during this final phase simulations are performed modeling the The MegaJOuLe Neutron Imaging Radiography (MJOLNIR) DPF with a variety of anode configurations. Variations on the anode length, shape, and the inclusion of a high density on axis gas jet are explored in order to find the configuration that provides the optimal target density and temperature for neutron production during the high-density pinch phase.