Modes of lightning attachment to aircraft at different stroke currents and relative positions of descending lightning leader

One of the major aspects of modern aircraft design is suitable protective measures against lightning which need a deeper understanding of the phenomena of a lightning strike to aircraft. Lightning attachment to aircraft can happen in two modes, aircraft-initiated and aircraft-intercepted. In the former, under the influence of thundercloud or lightning leader, the aircraft initiates stable bipolar leader discharges to complete the bridging. While in aircraft-intercepted mode, attachment takes place by direct streamer bridging between the lightning leader and aircraft. As different mechanisms are involved in the two modes of attachment, the corresponding probable initial attachment regions are also different. The mode of attachment is decided by the spatial field distribution, which mainly depends on the prospective stroke current and relative position of the descending leader. Different modes of attachment to aircraft are dominant at different stroke current ranges. The present work aims to identify the stroke-current ranges where aircraft-initiated and aircraft-intercepted modes are most probable. The investigation is carried out for small and medium-sized aircraft.