BALL-LIGHTNING - WHAT NATURE IS TRYING TO TELL THE PLASMA RESEARCH COMMUNITY

Ball lightning has been extensively observed in atmospheric air, usually in association with thunderstorms, by untrained observers who were not in a position to make careful observations. These chance sightings have been documented by polling observers, who constitute perhaps 5 % of the adult U.S. population. Unfortunately, ball lightning is not accessible to scientific analysis because it cannot be reproduced in the laboratory under controlled conditions. Natural ball lightning has been observed to last longer than 90 s and to have diameters from 1 cm to several metres. The energy density of a few lightning balls has been observed to be as high as 20 000 J/cm(3), well above the limit of chemical energy storage of, for example, TNT at 2000 J/cm(3). Such observations suggest a plasma-related phenomenon with significant magnetic energy storage. If this is the case, ball lightning should have very interesting implications for fusion research, industrial plasma engineering, and military applications, as well as being of great theoretical and practical interest to the plasma research community.