Three-fluid magneto-hydrodynamical simulation of plasma focus discharges

A two-dimensional, three-fluid code based on the two-fluid Potter code was developed for simulating the plasma focus discharge. With this code it is possible to treat the neutral gas in addition to the plasma components and to model the ionization and recombination phenomena. Thus one can study the sheet dynamics in a plasma focus and investigate effects such as the occurrence of residual gas (or plasma) density behind the current sheet in the run-down phase. This is a prerequisite to the occurrence of leak currents, which are one of the causes limiting the performance of large plasma focus devices. It is shown that fast operating foci with small dimensions behave favourably compared with the 'classical' Mather focus with long coaxial electrodes. (orig.)