A ring carbon plasma gun for the plasma opening switch

Summary form only given, as follows. A variety of quite different plasma sources are used with plasma opening switches to inject dense plasma into the region between the coaxial electrodes, with those normally used including flashboards, gas puff guns and the carbon plasma gun. The plasma produced when a laser beam impacts on a material such as carbon is also frequently used. The performance of the switch is characterised by the threshold current at which the opening mechanism begins and the duration of the conduction phase. Plasma parameters such as the distribution, concentration, electron temperature and ion species all contribute towards the switch performance. The carbon gun produces dense plasma by surface flashover of an insulator, although an even distribution is difficult to achieve when space restrictions limit the number of guns. The novel ring gun presented overcomes this problem and enhances the switch performance, by producing a surface flashover of the insulator between the electrodes that travels along a circular path. A study is presented of an experimental gun, using measured data provided by electrical probes and optical techniques. Supporting theoretical explanations are given.