On the different stages in the breakdown phase in plasma focus devices

Summary Form only given, as follows. The spatial location and the time evolution of the voltage between the electrodes in the so-called breakdown phase in plasma focus devices are currently being studied in the authors´ laboratory. A simple analysis of experimental data obtained so far with different electrode geometries has shown that this phase can be divided into three stages: (1) the breakdown proper, in which no measurable current flows; (2) a resistive stage of the discharge in which dI/dt rises to its first maximum and the ionization degree of the gas in the current circulating zone reaches approximately=1%; and (3) a sheath-formation stage, in which the ionization proceeds through thermal electron collisions and ends with the sheath take-off.<>