HED same-sided successive-shock instability experiments at the NIF *

The presence of multiple shocks interacting with multiple material interfaces is ubiquitous in ICF, but is often poorly validated in these complex systems. The LANL NIF MShock campaign is developing a capability to study RM/RT growth in a multiple layer, multiple-shock regime. We previously demonstrated the novel ability to generate 2 successive shocks from the same direction in a planar target. The physics of successive shocks accesses a much richer space than a single shock or an opposite reshock, not easily accessed in classical shock tubes. Idealized fluid theory [Mikaelian, PRA 1985] predicts 15 different growth cases for a single mode under successive shocks. Mshock single-mode and two-mode experiments demonstrate that perturbations can re-invert, freeze, or continue to grow based the experiment initial conditions, as predicted by theory. We are able to vary both the initial perturbation and the relative strengths and timings of the two shocks to vary the instability growth. Shock strength and timing experiments take advantage of a new simultaneous VISAR and imaging target that allows acquisition of a drive measurement and completed image data set in a single 3 shot, 24 hour sequence.