Prediction of Lightning Inception by Large Ice Particles and Extensive Air Showers

We derive that lightning can start if the electric field is 15% of the breakdown field, and if elongated ice particles of 6 cm length and 100 free electrons per cm³ are present. This is one particular example set from a parameter range that we discuss as well. Our simulations include the permittivity ε(ω) of ice. 100 free electrons per cm³ exist at 5.5 km altitude in air showers created by cosmic particles of at least 5×10¹⁵ eV. If the electric field zone is 3 m high and 0.2 km² in the horizontal direction, at least one discharge per minute can be triggered. The size distribution of the ice particles is crucial for our argument; more detailed measurements would be desirable.