Fig. 2.

Top view images of initial microbubble cavitation response, at t ≈ 11.4 μs, to a focused ultrasound burst of peak negative pressure = 1.5 MPa, with the propagation axis depicted by the red dashed line, for (a) a relatively isolated microbubble located centrally within the capillary, and (b) three microbubbles, two located centrally within the capillary and one closer to the wall. Flow within the capillary is left to right. Scale is provided by the internal diameter of 500 μm, and a flaw on the capillary (white arrowhead) acts as a convenient fiducial.