The rise of carbon fibre materials
Carbon fibre composite materials are now common within the aviation industry, including cabins for the latest generation of aircraft. Their electric conductivity is generally smaller and more anisotropic than in metals, but lightning safety must remain at the same level as for fully metallic aircraft, creating new challenges for aircraft construction and subsequent testing.
Gamma-rays
The high-energy radiation of gamma-rays, electrons and positrons in lightning discharges (discovered as TGFs), could pose completely new lightning protection problems for aircraft, due to the eventual delivery of a large dose to aircraft electronic equipment within a few milliseconds. The radiation inside aircraft has been measured in recent aircraft experiments.
Lightning networks
Lightning detection systems on the ground rely on the electromagnetic (EM) radiation from the lightning where a group of sensors measures the waveform and a common predefined signature identifies a lightning event. Operational grade networks are typically only sensitive to cloud-to-ground lightning and give the time, location, peak current and the multiplicity of strokes. Recent advances in network techniques include denser networks with ~25 km baselines that measure the full lightning discharge in 3 dimensions, including intra-cloud lightning, and networks with long distances (~1000 km) between sensors that measure global lightning activity, notably also over oceans and in less-industrialized countries without national networks. For all networks, considerable effort goes into the determination of their sensitivities.
Detection from satellites
A technique has also been developed that detects lightning optically from satellites. The vantage point of space gives a high detection efficiency of intra-cloud lightning and captures most lightning to ground. Optical detectors are planned for the next generation geostationary meteorological satellites of EUMETSAT and NOAA, building on the ISS-LIS technology. It is therefore of considerable interest to characterize the strong and weak points of lightning detection systems from ground and space and to study the potential which lies in their combination. It is also of interest to push the boundaries of current scientific knowledge further to identify underlying micro-processes of lightning and their signatures in sensitive detection systems.
High voltage technology
Discharges play a key role in plasma technology and in high-voltage engineering. The conversion of electric energy into chemical reactants within a discharge is widely used in spark plugs of car engines and in ozone generators for disinfection. Very actively investigated topics include plasma medicine, plasma assisted ignition and combustion, plasma processing and plasma assisted conversion of solar power into liquid fuel. In high voltage technology, corona discharges dominate energy losses along high voltage electricity lines and they are detrimental when short-circuiting insulating layers. They are also the key ingredient in electrical circuit breakers in our electricity nets where important questions are now how to replace the highly insulating SF6 gas by a less polluting medium and how to design circuit breakers for possible future dc electricity nets.