Analysis of striking distances of lightning strokes to vertical towers

The two criteria (E- and V-criterion) concept is proposed for estimating the striking distance of a stepped leader to a vertical tower. The tower was modelled as a stack of ring charges by charge simulation method. It was found that the radial striking distance to a vertical tower varied with the lateral distance of the descending stepped-leader tip from the struck object. The lateral striking distance is defined as the farthest lateral distance of the stepped-leader tip from the vertical tower that produces a strike. The stepped-leader parameters, such as the height, charge distribution and polarity, affect the striking distance to the tower. Because of the stochastic nature of these parameters, the statistical variations of these parameters must be known. The tower height and radius also affect the striking distance to the tower.