Investigation of streamer-leader transition during upward lightning

Upward lightning requires a different approach than downward (cloud-to-ground) lightning. Some of the lightning strikes are triggered by the ground object itself. Whether it happens is dependent on e.g., the geometric dimensions, the structure, and the relative location of the object in its environment, as well as the charge location and distribution in the thundercloud. A computer simulation is featured in this article to investigate the phenomenon. A realistic wind turbine model is selected for the computation along with a thundercloud. Investigation of the thundercloud model is carried out to ensure its applicability to study the streamer-leader transition process. The simulation tracks the amplitude of the electric field between the turbine and the cloud initiated by the charge of the thundercloud with respect to the above-mentioned influencing factors. This electric field leads to a corona discharge and possibly a streamer on the rotor blade tip which might evolve into an upward leader. Calculations are carried out for different cloud heights in the interest of the parameters of the upward leader. The aim of this work is to determine the possible thundercloud heights for the initiation of an upward leader.