Seeding the m $=$ 0 instability in dense plasma focus (DPF) Z-pinches with a hollow anode*

The dense plasma focus (DPF) is a classic Z-pinch plasma device that has been long studied as a copious source of various types of radiation. The formation of the m $=$ 0 plasma instability during the compression phase is linked to the generation of high-energy charged particle beams, which, when operated in deuterium, lead to beam-target fusion reactions and the generation of neutron yield. Here we present a novel technique of seeding the m $=$ 0 instability by varying the anode's hollow inner diameter. As the plasma sheath moves along this hollow anode structure, a low density perturbation is formed and this seeds the instability. Dynamics of the low density perturbation and seeding of the m $=$ 0 instability are studied in detail with fully kinetic plasma simulations performed in the LSP particle-in-cell code on a 60 kA device. It is discovered in the simulations that the neutron yield of the DPF may be significantly improved and made more consistent by employing an anode geometry with an appropriate inner hollow diameter.