Mechanism of the lightning flash

More than 200 years have passed since Benjamin Franklin first demonstrated that thunderclouds are electrified, but the exact mechanisms by which the charges are generated, separated, and dissipated in lightning flashes are still the cause of much research and argument. Although there has been no shortage of theories, none has withstood the test of time and the accumulation of detailed information concerning the structure and behaviour of thunderstorms as revealed by aircraft, radar and balloon-borne instruments.