On-the Lichtenherg's Figure of the Damped Oscillatory Discharge Obtained by Using Rotary Film

Abstract

The Lichteinberg's figure produced by the damped oscillatory discharge is investigated, by arranging electrode to act on the rotary sensitive photographic film, and following facts are observed.
I. Case with a needle electrode placed on the rotary drum acting as an another electrode.
(1) When the first half wave is positive, the neg. figure of the next half wave, loses its characteristic form and creeps over the same bath as the previous pos. one.
(2) When the first half wave is negative, the pos. figure of the next half wave, maintains its characteristic form, but its path is not straight and proceede tangentially near the extremity of the previous neg. charge.
(3) The ratio of the radius of the pos. and neg. figure of the first half wave, is far greater than that of the next half wave.
(4) Connecting the two electrodes placed on the rotary film to the lead wires different inductances the figure produced by the electrode with the greater inductance is larger than that produced by the electrode wish the smaller one.
II. Case with the needle electrodes placed on the opposite sides of a rotary insulator disc.
While the discharge is in the state of pole-brush, the pos. figure obtained on one surface has longer creeping distance, compared with the neg. one on the opposite surface, but the pos. figure in the state of surface-spark-co one has the same creeping distance with the neg. one, and the discharges of both sides seem to restrain each other.
Examining the spark by means of a rotating mirror, the lowest frequency of damped oscillatory discharge obtained in these arrangement was ascertained to be the order of about 1.1×105 cycles per sec.