Investigation of process of spark discharge development in long air gaps under lightning protection testings on aircraft models

This paper presents the results of experimental investigations of process of spark discharge development on the floating aircraft models in long air gaps. Tests were fulfilled for both impulse polarities and for different gap length, impulse parameters, and model location in the gap. Analysis of received data allows the conclusion that development of the reciprocal leader from the model occurs within the limits of streamer zones of the descending leaders. Also, it was found that for development of negative leader conditions for the reciprocal leader development from aircraft model is fulfilled earlier than the boundary of streamer zone of the main descending leader as it closely approaches the aircraft. So, it can be suggested that this increases the descending lightning attraction radius by aircraft from which surfaces the reciprocal leaders are initiated