A sequential plasma focus

Abstract

Shadowgraph studies suggest that a target disk placed downstream of the anode of a plasma focus may become an auxiliary anode producing a second focusing event when the current sheet climbs over it after the first focus event. A model is put forth in which each event is assumed to comprise three phases: an axial phase, a radial phase, and a radial extension or expanded column phase. This model produces the current dip, voltage spike, and high radial speeds characteristic of a plasma focus. With two separated disks acting as auxiliary anodes downstream of the usual anode, there are three focus events with nine phases in the computation. The results of the model indicate that each anode produces sequentially the current dip, voltage spike, and high radial speeds characteristic of the plasma focus. These computations suggest the possibility and design of a sequential or cascading plasma focus. >