Lightning discharges triggered using rocket-and-wire techniques

Classical and altitude rocket-and-wire techniques for triggering lightning discharges are described. Various characteristics of triggered lightning derived from measurements of current at the lightning channel base and from close electric and magnetic field records are reviewed. New insights into lightning processes gained from triggered-lightning experiments are discussed. Important findings include (1) evidence of independence of the return-stroke peak current of grounding conditions, (2) the characterization of the close (within tens to hundreds of meters) lightning electromagnetic environment, (3) direct evidence of the upward connecting discharge in a dart leader/return stroke sequence, and (4) discovery of the mechanism of the lightning M component.