Lightning attraction mechanism and the problem of lightning initiation by lasers

Physical processes determining the ability of a lightning to change its tra jectory to strike the highest construction available are discussed. The lea der mechanism of lightning propagation is explained. The criterion for a vi able upward leader to start from a construction is established. The mechani sm of a weak long-distance interaction between the upward leader starting f rom a construction and the downward leader counterpropagating from a cloud is analyzed. Current problems concerning lightning protection and lightning initiation by a laser are discussed, the latter being of special interest owing to a recent successful experiment of this kind.