Experimental Investigation of the Three-Dimensional Interaction of a Strong Shock with a Spherical Density Inhomogeneity

Laser-driven experiments are described which probe the interaction of a very strong shock with a spherical density inhomogeneity. The interaction is viewed from two orthogonal directions enabling visualization of both the initial distortion of the sphere into a double vortex ring structure as well as the onset of an azimuthal instability that ultimately results in the three-dimensional breakup of the ring. The experimental results are compared with 3D numerical simulations and are shown to be in remarkable agreement with the incompressible theory of Widnall et al. [J. Fluid Mech. 66, 35 (1974)].