Study of Ultraviolet Emission and Visible Discharge along an Ice Surface

The propagation characteristics of an electric arc on an ice surface have been investigated using high-speed imaging technique. The light emission in both UV and visible regions under ac voltage during the arc propagation has been recorded using an ultra high-speed camera and an image intensifier. The initiation and propagation of discharge in the air gap and along the ice surface were observed, and the discharge propagation velocities at different stages were recorded. These studies have revealed, beyond the main discharge, the presence of luminous spots which determine the path of discharge and accelerate its extension. The effect of surface conductivity on the propagation velocity has been evaluated for different water conductivities used to form the ice. The mechanism of energy supply to the arc which could describe the propagation velocities in different stages has been discussed.