Investigating Richtmyer-Meshkov Instabilities at High Energy Densities on the Z Machine*

Hydrodynamic instabilities are ubiquitous in inertial confinement fusion implosion scenarios, leading to loss of energy for compression and to mix of dissimilar materials. In order to study them and assess their impact, dedicated instability experiments have been performed using the Z Machine at Sandia National Laboratories. Complementary to laser-driven instability experiments, pinch-driven experiments naturally drive interfaces in their light-to-heavy configuration and include the effects of cylindrical convergence. We present experimental results and simulations of a suite of platforms investigating the Richtmyer-Meshkov (RM) process and interfacial feedthrough. Liners filled with liquid deuterium are magnetically imploded, driving a converging shock to the central axis and creating a magnetically isolated region suitable for studying hydrodynamic processes. The first platform investigates the interaction of this shock with a solid beryllium rod machined with sinusoidal perturbations that then grow under RM. The second replaces the on-axis rod with another cylindrical liner, enabling investigation of the feedthrough of these instabilities to the inner surface.