Study on the development process of ejected plasma used as a trigger method in gas spark switch

Abstract

Ejected plasma used in gas spark switch has been proved efficient as a trigger method. However, the development and trigger mechanism are still to be revealed. In this paper, an experimental platform was built to investigate the influence of trigger pulse energy and polarity on the space-time shape evolution characteristics and the ejecting characteristic of ejected plasma. The results indicate that the head of the plasma would depart from its body leading to the separation of the head and tail. Furthermore, some branches could be observed in the following few microseconds. Especially when negative pulses with higher energy were applied onto a gas gap, the ejected plasma seemed to be brighter and larger. As for the ejecting characteristics of the plasma, the height of the plasma was of the order of mm, and the velocity was of the order of 105mm/μs. Not only the height but also the velocity was higher when larger pulse energy and negative pulse were applied.