Abstract:
Drops of water falling on a plane water surface are known to produce vortex rings which carry vertical momentum away from the surface. A similar phenomenon should also occur in a cavity which collapses asymmetrically: An inward jet will also produce vortex rings on impact with the opposite wall of the cavity. It is suggested that the phenomenon may be taking place on each cycle of collapse of a single sonoluminescing bubble. The transport of jet momentum away from the bubble by the vortex rings should help to restore the bubble, on rebound, to a spherical shape.