Lawrence Livermore National Laboratory (LLNL) researchers have developed a new simulation capability to model a classic plasma configuration. They have demonstrated for the first time a fully kinetic model of the dense plasma focus (DPF) Z-pinch device, including the electrodes, in a realistic geometry. Fully kinetic calculations allow for the physical quantities to be tracked at the particle level. Many previous calculations took a "fluid" approach, averaging physical quantities over many particles, which washes out beam formation and non-classical plasma resistivity effects.
The Z-pinch is a classic, and arguably the first, plasma configuration but it still defies scientists' ability to fully predict and understand its behavior. In a Z-pinch, a pulsed high current arc discharge between two electrodes causes a plasma column to implode under its immense self-generated magnetic pressure. Yet scientists still do not fully understand how these devices emit such high energy (multi-MeV) charged particle beams.
The new simulations have reproduced key features of these plasmas, including the ion beam and neutron outputs. In addition, the team observed signatures of a type of instability that has always been postulated to fundamentally drive the dynamics in these plasmas.
The team's results show initial kinetic simulations, which reproduce experimental neutron yields and high-energy beams for the first time. This simulation tool will be used to further unravel the unknowns of this age-old plasma configuration.
