Figure 3. Travel in capillary waves.

In a single bursting event, the travelling distance of capillary waves was graphically measured as L∼0.53πR, where R is the initial bubble radius, from the snapshots (Fig. 2b) obtained by ultrafast X-ray imaging. The blue dot indicates the wave crest. The average value from five different events is L∼0.53±0.02πR, and the approximation L≈0.5πR was used as the travelling distance in the text. Scale bar, 60 μm.