Field-enhanced propagation of corona streamers

Abstract

Experiments are described in which the lengths of positive and negative streamers, propagating within a region characterized by a uniform electric field, are determined as a function of field strength. Streamers were generated from the application of a short rise‐time voltage pulse to a point electrode and from field‐induced hydrodynamic instability of a falling water drop. Positive streamers display marked length enhancement with ambient electric fields in the direction of propagation greater than about 6×105 v m−1 and lengths apparently limited only by the spatial extent of the field above about 7×105 v m−1, depending somewhat upon the absolute humidity of the air. Negative streamers show only a small length enhancement with ambient fields as high as 8×105 v m−1. The results with positive streamers are discussed in terms of a model in which the propagating tip becomes isolated from its anode source and derives energy from interaction with the ambient electric field. Since the ambient field within an active thundercloud may reasonably attain the necessary strength for long‐range propagation, these results suggest that positive streamer processes may be very important in charge drainage and in altering the droplet charge spectrum.

Fundamental processes in long air gap discharges

“…It has been shown that the stability field is equivalent to the average field along the streamer extension [20]; therefore, if the average field is fixed, the corona length is directly given by the geometric construction of Fig. 6.…”

Measurements of lightning rod responses to nearby strikes

“…Our assessment of the experience gained since Franklin's time is that sharp rods exposed in isolation on church steeples and other high towers are often struck by lightning whereas similarly sharp Franklin rods installed with lesser isolation are sometimes not struck, other objects in the vicinity being the strike receptors. Phelps [1971] a radioactive "ESE" device and two strikes were also adjacent to a sharp, high-tech, French "air terminal" (which was tested for only a three year period).…”

Electrical Balance in the Lower Atmosphere

“…This equipment has given values in excess of 4 x 105 V 1m (Winn & Moore, personal communication) a value appreciably larger than that obtained by Gunn and one that, when corrected for atospheric pressure, closely approaches the value of electric fields observed by Phelps (41) to be necessary to sustain positive streamer development.…”