Filamentary structure of streamers in Transient Luminous Events

The subject of the seminar will be a numerical modelling of instabilities in a weakly-ionized plasma with a use of kinetic theory plasma models. The natural phenomenon being treated is the process of branching (filamentation) of a sprite's streamer. Sprite is a visual phenomenon of Transient Luminous Events (TLE) family which occurs above large and intensive thunderstorms. Its filamentary structure tends to branch in a way similar to the lightning channel, but the underlying mesospherical environment is different. A possible kinetic plasma instability related to this branching was analysed by Błęcki & Mizerski (2018), however the modelling revealed that non-linear effects set on early in the simulations. Other possible filamentation instabilities will be also elaborated.