How lightning starts, is a major question in atmospheric electricity, in the scientific literature as well as in the media. Characterizing and understanding this process from molecular scales to millimetres to meters to hectometres is a challenge for observations, experiments and modelling. It also can provide a key to quantitative understanding of other lighting phenomena, including green house gas emissions and lightning protection questions.
In the focus session, four researchers will present their complementary methods and results on the initial stages of lightning discharges. Steve Cummer will discuss observations of very energetic “narrow bipolar events”. Brian Hare uses the Dutch-European radio telescope LOFAR to resolve lightning structures down to the meter scale. Sander Nijdam will present unique lab experiments on discharge inception and propagation with nanosecond resolution, and Ute Ebert will review the state of multiscale theory, building on simulations, model reduction and nonlinear dynamics.