Abstract
The charaeterises of the spark discharge are studied with special reference to the action of the residual charge distributed along the traces of the brash discharge, for the cases :- (1) With a portion of a resonant wave. (2) With an uni-directional pulsating wave. The inference from the test results can be summarized as follows:- (1) The spark-over distance increases gradually as the frequency increases from 50 cycles to about 3 x 10_??_ cycles, beyond which it decreases rapidly and approaches the value fur the case of a single impulse with its tail chopped off by means of a sphere gap of the same length. (2) The positive Lichtenberg figure produced by an uni-directional pulsating potential with two voltage peaks shows that the discharge spreads radially to the extent correspondhing to the first voltage peak; but the subbequent discharge due to the next voltage peak takes place, spreading along the traces of the previous shoot for some distance, and then proceeding just between the streaks of the former discharge. (3) In the case of an uni-directional pulsating wave, the positive sparkover distance is always longer than that for a single impulse; for the negative discharge, however, it is reversed. The above results are discussed form the consideration of the phenomena such as the mobility of ions, their diffusion and the variation of potential gradient by the space charge. The characteristics of the spark discharge have been investigated, particular attention being paid to the relations between the form of the Lichtenberg figure and the wave shape of the applied voltage
