The NIF Re-Shock platform for studying Rayleigh-Taylor and Richtmyer-Meshkov instabilities in a planar geometry*

We discuss experiments at the National Ignition Facility (NIF) studying the nonlinear Richtmyer-Meshkov and Rayleigh-Taylor instabilities of a multiply-shocked plasma interface in a planar geometry.¹  Similar “re-shock” experiments have been done in classical shock tubes for many years. Laser-driven systems present new opportunities for this type of experiment, in particular the ability to precisely vary a range of parameters, including the strengths of the shockwaves, the initial perturbation of the unstable interface, and the densities of the mixing materials.  This talk will describe design and optimization studies of a double-ended shock tube target for the NIF capable of generating and characterizing the hydrodynamic instability growth of both single- and re-shocked perturbed planar interfaces.  The platform includes the ability to diagnose both the extent of the penetration of the heavy fluid into the light fluid as well as the light fluid into the heavy through a novel combination of target materials.  We present data from the NIF on a variety of experimental conditions, and discuss the computational hydrodynamics simulations that have been developed to simulate these experiments.

 

1. Nagel, S.R. et. al.  2017.  A platform for studying the Rayleigh–Taylor and Richtmyer–Meshkov instabilities in a planar geometry at high energy density at the National Ignition Facility. Physics of Plasmas, 24(7), p.072704.