Investigation on mechanisms in sprites leading to green emissions in the lower ionosphere

International audience; Green emissions produced in the upper regions of sprites discharges have been recently observed and posted publicly online. They are now commonly referred to as Green Ghosts. There is a wealth of high-quality observations of TLEs captured by enthusiasts. Newly launched NASA citizen science project "Spritacular" (spritacular.org) aims to generate a database of TLEs captured by the public and present it to the science community as a new source of ground-based observational data that can be readily utilized in scientific studies. In this presentation, we investigate how this unforeseen emission can be explained in the context of sprites using results from streamer simulations, simplified chemistry modeling of the lower ionosphere, and spectroscopic analysis. We particularly focus on reproducing the intensity and time dynamics of the phenomenon.