Ball Lightning: What Nature is Trying to Tell the Plasma Research Community

Abstract

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/cm³, well above the limit of chemical energy storage of, for example, TNT at 2000 J/cm³. 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.

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Notes on contributors

J. Reece Roth

J. Reece Roth (SB, physics, Massachusetts Institute of Technology, 1959; PhD, engineering physics, Cornell University, 1963) joined the National Aeronautics and Space Administration (NASA) Lewis Research Center in Cleveland, Ohio, in 1963, where he was principal investigator of the Lewis Electric Field Bumpy Torus Project until 1978. At present he is on the faculty of the electrical and computer engineering department of the University of Tennessee, Knoxville. While at NASA, Roth pioneered in the application of superconducting magnet facilities to high-temperature plasma research. This work included a superconducting magnetic mirror machine, which was put in service in 1964, and the superconducting Bumpy Torus magnet facility, which was put in service in 1972. Roth initiated research on the electric field Bumpy Torus concept, an approach to creating a plasma of fusion interest in which strong radial electric fields are imposed on a Bumpy Torus plasma in such a way that they contribute to the heating, stability, and confinement of the plasma. Among his contributions to the understanding of basic processes in plasmas are his experimental discovery of the continuity-equation oscillation and of the geometric mean plasma frequency, a new mode of electromagnetic emission from plasmas.