Advanced diagnostics on streamers and an outlook on lightning in a bottle.

This contribution is split into two topics. Both focus on streamer-like discharges, with the first part presenting recent results, while the second part is an outlook for our new set-up.

Firstly, we discuss recent results using advanced diagnostics on streamer discharges. These diagnostics include E-FISH and fast imaging. We look at the limits of measuring the electric field strength by E-FISH when investigating repetitive single channel streamer discharges in air-like gas mixtures at reduced pressures and the application of E-FISH on single filament dielectric barrier discharges (DBDs) in N₂-O₂ gas mixtures at atmospheric pressure. We use fast imaging to study streamers in more challenging gas mixtures like CO₂ and C₄F₇N which have a much more stochastic behavior than air-like mixtures, with the primary application as insulating gas in high voltage circuit breakers.

Secondly, we discuss a new set-up currently being built for laboratory experiments on the fundamentals of lightning. This set-up consists of a large (> 6 m³) discharge vessel in which long streamer discharges (i.e. about 1 m long) can be made in a controllable way with optical access to the discharge path. Furthermore, a full electrical characterization is planned, i.e. the proper measurement of applied voltage and discharge current, which is a challenging task, since we will eventually use > 500 kV pulses with rise-times of order 10 ns and repetition rates of tens of Hz. With this we will investigate how lightning initiates, how it propagates (including the evolution from streamers to leaders) and how it can emit x-rays and other high-energy radiation.