Initiation and development of first lightning leader: The effects of coronae and position of lightning origin

This paper addresses, by means of numerical simulations, the issues of lightning initiation near tall, grounded objects and lightning development in the cloud-to-ground gap. Taken into account is the effect of coronae on the initiation of an upward leader from the top of a fixed grounded structure that is exposed to the electric field produced by the storm-cloud and approaching downward leader. It is shown that the potential carried by a downward leader to the ground and, consequently, the return stroke current depend greatly on the position of a bi-directional leader origin inside a cloud and on the shape of the leader path.