The physical concept of recoil leader formation

The concept of recoil leader formation is based upon their nature as bidirectional and bipolar leaders. The analogy of the unipolar leaders to free-burning arcs was applied to interpret the processes during current cutoff in individual leader branches. These processes are essential to locating the origin and the timing of recoil leader formation. The difference in the density of the branching structures of positively- and negatively charged leaders is shown as the decisive factor affecting the occurrence of recoil leaders in positively charged channels, absence of them in negatively charged channels, and the lack of multiple return strokes in positive cloud-to-ground flashes.