Vortex stability and clumping along a shocked high-energy-density cylinder*

The formation of mass clumps in circumstellar environments has been theorized to result from a hydrodynamic mechanism known as the Crow instability. Specifically, shear from solar wind induces the formation of a counter-rotating vortex pair, which supports the growth of symmetric perturbations that eventually pinch off into the observed clumps. An analogous flow may be examined by generating the vortex pair with a shock wave passing laterally through a heavy gaseous cylinder. Our objective is therefore to examine the feasibility of an experiment on clumping induced by the Crow instability along a shocked cylinder. A scaling law is developed to determine the spatiotemporal scales of the instability development, which suggests that a shocked cylinder with an initial diameter of 100 micrometers consisting of a radial perturbation of approximate wavelength and amplitude of 600 and 10 micrometers, respectively, is expected to form clumps resulting from the Crow instability approximately 40 nanoseconds after it is shocked, with dynamics which can be readily visualized on the Omega EP laser facility.