Path of the Trigatron Spark

Abstract

IN a recent investigation¹ into the characteristics of the trigatron² spark gap, an interesting effect was observed in connexion with the path taken by the spark discharge between the spherical electrodes. Several hundred discharges were observed and each spark appeared to consist of two parts. The first was a straight part along the axis of the gap and reaching from one electrode to a distance of 10–50 per cent of the gap-length. The remainder was of the familiar tortuous nature of a spark discharge. The discharges were photographed from two directions at right angles, using mirrors and using the camera shutter in conjunction with a relay to trigger the spark. The effect occurred with regularity and was quite definite. It was found that the straight part of the spark was always that part adjacent to the anode, whatever the polarity of the high-voltage electrode. A typical photograph illustrating the effect is shown in Fig. 1, where the straight part of the spark is 20 per cent of the total gap-length.