The project is divided into experimental, observational and theoretical work.
Out of 15 student projects, 5 started their projects in modelling, 6 on observations and 4 on laboratory experiments. During the first two years, three schools were organized training new, upcoming researchers and fostering collaborations between all participating partners.
Observational students started working on ground-based as well as on satellite data. Satellite data was explored using the Atmosphere-Space Interactions Monitor (ASIM) together with the Lightning Imaging Sensor (LIS) on the International Space Station. The analysis of terrestrial gamma-ray flashes (TGFs) relative to lightning activity required microsecond accuracy between the optical and x- and gamma-ray instruments which is now completed. More than 50 TGF events with simultaneous optical observations of lightning activity have been analysed and hundreds of events are ready for further studies allowing the identification of the lightning process that generates TGFs.
Parallel to the work with satellite data, observational campaigns were started. The first campaign was conducted in January 2018 by the University of Bath in collaboration with the South African National Space Agency at the Square Kilometre Array (SKA) site near Carnavon in the Karoo desert in South Africa. It was found that the site offers excellent optical observation opportunities for thunderstorms occurring in the north-east of South Africa near Losotho. In addition, the electromagnetic environment was found to be of an outstanding quality which offers novel opportunities for array measurements to be conducted during field work to study transient luminous events planned for 2020. Some first observations of TLEs with high speed cameras have been conducted.
In addition to observations, laboratory experiments were conducted. A set-up has been built which is able to measure discharge inception from metal and dielectric materials in unprecedented detail. It comprises of a vacuum vessel, a photo-multiplier, a high voltage pulse source, an ICCD-camera and electronics and software to enable automated measurements. Custom dielectric particles mimicking ice have been produced.
On the simulation side, a model to understand lightning attachment to wind turbines is developed. The emphasis of the study is in particular on density variations of the air flow near the blades, that can have an impact on the discharge evolution and hence on lightning inception. Another approach is to develop a computational model based on GPUs (Graphics Processing Units) rather than on CPUs (Central Processing Units) in order to simulate discharge processes. The new approach shows first promising results that can be tested against codes of other groups.
