New and improved technology is allowing for the discovery of lightning processes that were previously unable to be observed. Lightning researchers are using this new data to adjust their theories on fundamental questions related to how lightning initiates and propagates. In this award, new instrumentation will be deployed at the Lightning Observatory in Gainesville (LOG) in Florida to capture the details of lightning across a broad range of the electromagnetic spectrum, including new measurements of high-energy X-rays. Improved understanding of lightning processes are important for improved predictive capabilities and development of lightning protection options. The project will also provide training and mentorship for students and a post-doctoral research scientist. This award will address a number of open scientific questions about lightning using data across the electromagnetic spectrum. For this study, the researchers will use high-speed cameras in the visual range, an infrared camera, an ultraviolet imaging system, and a new high-speed X-ray imaging system, all deployed from a rooftop on the University of Florida campus. The specific tasks are to: 1) Study the mechanisms of leader-stepping and attachment processes in negative and positive lightning, 2) Investigate the post-return-stroke processes, including continuing current and channel decay, 3) Conduct high-speed imaging of lightning in the X-ray/gamma-ray bands, and 4) Study bipolar lightning flashes with m