On the second light flash emitted from a spark-generated bubble oscillating in water

Anotace: The light emitted from the spark-generated bubbles oscillating in water is studied experimentally. Attention is paid to the emission of light from bubbles in the final stages of their first contraction and in the early stages of their following expansion. In some experiments, two close flashes of light were observed. The first light flash has already been studied in earlier works. In the present work, attention is paid to the second light flash. The relations between the first and second flashes of light and the size of the bubbles are studied and discussed in detail. It is assumed that these two light flashes are caused by two different processes taking place in the bubbles. The possible nature of these two processes is briefly discussed.