A transition from negative to positive streamers under a guiding field

Abstract

A transition from a negative regime to positive streamers in a guiding field has been studied. The apparatus is a simple parallel plane electrode arrangement that provides the uniform guiding field. Negative streamers were generated by a pulsed negative voltage of magnitude ≈5 kV and duration ≈270 ns applied to a trigger pin electrode placed in an aperture at the centre of the grounded electrode and insulated from it by air. It has been shown that the velocities of streamers was between 4×104 and 1.5×105 m s−1 over an external guiding field range of 5.5–6.3 kV cm−1. Results have been presented showing the variation of field in the mid-gap region and the characteristics of streamers. Optical observations have shown the light emission from the developing discharge to be non-linear.