On the Localized Afterglows Observed with Long Sparks in Various Gases

Abstract

Simultaneous photographs, taken in two perpendicular directions, have been obtained of long sparks in various gases at 1-atmosphere pressure. The experiments were undertaken in order to decide whether the localized afterglows, noticed as long streaks in rotating mirror spark photographs, were caused by some discharge mechanism or by purely geometrical effects resulting from the tortuous nature of the spark channels. The results show that the second explanation is not feasible. Some qualitative interpretations of the effects are given.

Ball lightning as a physical phenomenon

“…On the average, in about 15 msec after a stroke the electrical conductivity of the channel is reduced to such a low value that a new leader stroke is required for a second discharge to pass in the same channel, whereas in 100 msec the channel loses its ionization quite completely unless a second stroke ensues [Schonland, 1956; Malan, 1956]. Similarly, observations of afterglow phenomena in spark discharges in gases at atmospheric pressure indicate that the luminosity decays in a time of the order of I msec or less [Craggs, Hopwood, and Meek, 1947].…”