On the Development of Upward Streamers from a Tree-shaped Multi-needle Arrangement during Progress of a Downward Leader

This paper is aimed at investigating the development of an upward streamer from a grounded tree-shaped
multi-needle arrangement during the progress of a downward leader. The downward leader is simulated by a point charge at tip and a finite line charge extending along the leader length. The field enhancement in the vicinity of the needle arrangement in presence of the downward leader is assessed using the charge simulation method. The onset condition of the upward streamer is formulated under the prevailing electric field. The temporal development of the streamer during the progress of the downward leader is assessed and the streamer current waveform is predicted. The current waveforms agreed reasonably with those recorded previously for positive streamers emanating from sharp points. The obtained results are discussed in the light of air discharge physics.