Genesis of column sprites: Formation mechanisms and optical structures

Abstract: Sprite discharges are electrical discharges that initiate from the lower ionosphere during intense lightning storms, manifesting themselves optically as flashes of light that last a few milliseconds. This study unravels sprite initiation mechanisms and evolution into distinctive morphologies like glows and beads, using direct 3D numerical simulations that capture the intricate electrical discharge processes. We clarify various morphological aspects of sprites such as the halo dynamics, column glows, branching, streamer reconnection, and bead formation. The results advance our understanding of sprites and their connection to thunderstorm dynamics, and puts quantitative analysis of their effect on Earth's climate within reach.