Bifurcation from bubble to droplet behavior in inviscid pinch-off.

High-speed video is used to analyze the pinch-off of xenon in water. By varying the pressure in the xenon from 0.05 to 68 atm, the mass density ratio D=rho(int)/rho(ext) of the interior gaseous xenon rho(int} to the exterior liquid water rho(ext) can be varied by over 3 orders of magnitude. Both the shape of the pinch region and the power law that governs the collapse of the minimum neck radius are distinctly different for the low D (bubblelike) and high D (dropletlike) cases. We show that there is a rather abrupt transition between these types of behavior near D approximately 0.25.