Imaging Electrical Discharges and Lightning
High voltage discharges produce excitation of nitrogen in the air, leading to emission of a deep purple light that also has a strong UV component. Nitrogen glows brighter in the UV band than in the visible band. The Tesla coil shown below makes electrical discharges that are approximately 20″ long. This UVCorder image shows a great deal of branching structure in the discharges not apparent to the eye.
We have found that the UVCorder is not very sensitive to the UV signal from low-level corona discharge. Solar-blind UV cameras based on microchannel plate amplifiers are much better suited for this application. We recommend the excellent DayCor camera, which was specifically designed to image corona discharge. The DayCor can be found with a simple Google search.
Electrical discharge from a Tesla Coil imaged in the UV band by UVCorder™