Modelling Discharge Inception in Thunderstorms

Tuesday, 16 December 2014: 11:20 AM
Casper Rutjes1, Anna Dubinova2, Ute Ebert2, Stijn Buitink3, Olaf Scholten4 and Gia Thi Ngoc Trinh4, (1)Center for Mathematics and Computer Science, Amsterdam, 1098, Netherlands, (2)Center for Mathematics and Computer Science, Amsterdam, Netherlands, (3)Radboud University Nijmegen, Nijmegen, Netherlands, (4)University of Groningen, Groningen, Netherlands
The electric fields in thunderstorms can exceed the breakdown value locally near hydrometeors. But are fields high enough and the regions large enough to initiate a streamer discharge? And where would a sufficient density of free electrons come from to start the discharge in the humid air that rapidly binds electrons in water-clusters?

To analyse these questions, we investigate the interaction of extensive air showers (created by high energy cosmic particles) with the hydrometeors in a thunderstorm. The extensive air showers are modelled in full detail with CORSIKA ( As extensive air showers are occurring with a frequency that strongly depends on their size, proper stochastics are derived to cope with the large number of random variables in the system, such as: occurrence, primary energy, altitude of first interaction and inclination. These variables are important factors that determine the extremes of the high energy particle flux passing through a hydrometeor at a given altitude. In addition, the interaction of the high energy particle flux with the hydrometeor is modelled with EGS5 ( Finally the streamer initiation and evolution is modelled by our 2.5D streamer fluid code that now can include dielectric bodies; here we used the frequency dependent dielectric permittivity of ice, accounting for the fact that ice can not polarise instantaneously.