Spectroscopic Measurements of Light Emissions from High Current Arcs

Due to the destructive impact of lightning, and the risk of increasing strikes attributed to climate change on the natural and built environment, work has been carried out to study the temperature and light emitted by laboratory generated lightning using non-invasive light-based instrumentation, which will allow optimisation of lightning protection. Using spectroscopy, the optical emission spectrum of a 55 kA lightning arc with a copper fuse wire was obtained for study. The results showed the light radiated in the visible and infrared range, with strong copper emission lines seen, and determined a temperature of the arc of 8,531±577 K. This is in preparation for subnanosecond resolution data to be recorded using a new streak spectrograph to create temporal data of lightning arcs. A new laboratory experimental set up is being developed to explore further electromagnetic emissions in the infrared, ultraviolet and x-rays, to derive other useful information about lightning phenomena.