A set of optical techniques for studying the dynamics of a discharge in millimeter-length intervals: the development of a spark discharge in air in the pin-to-plate geometry

Abstract

Techniques are described and some results of experimental studies of a spark discharge in the tip-plane geometry in air at atmospheric pressure are presented. It is shown that, at the initial stage (a few nanoseconds after breakdown), the microstructure of the discharge is formed in the form of a set of a large number of microchannels. It was found that by the moment of time 20 ns the spark channel acquires a single cylindrical boundary, the electron concentration at this moment reaches a maximum value of 2-1019 cm−3, after which an intense expansion of the channel begins, and from 60 ns a shock wave leaves its boundary.