Pairwise Strength Determination from Rayleigh-Taylor Instability Growth Designs for Laser Driven Experiments

Probing material strength at high-pressures by the suppression of Rayleigh-Taylor (RT) growth is complicated by numerous experimental and material concerns required to achieve specific conditions in a sample. Among these concerns is the requirement to maintain ripple growth within a band of measurable, linear response while ensuring sufficient sensitivity to material strength beyond the experimental error bars. One solution is to use a combination of low, medium, and high-density materials as pusher-sample pairs, from which the strength of each may be determined from measurements made using a combination of at least three of these pairs. The loading path of these pairwise combinations, however, must be sufficiently similar in all cases. This work describes the use of shaped laser pulses to induce the desired compression path in pairwise combinations of materials, along with an appropriate common ablator layer, ablation X-ray shield and tamper. Ripple growth is measured and subsequently, strength is inferred from face-on radiographs that are compared to simulated growth factors using different strength models. The pairwise designs employ a combination of 1D and 2D simulations where the growth factor is calculated through an areal density integration method. We report simulation designs using Epoxy, Al, Sn, Cu, and Au pairs to investigate and establish a set of consistent strength models and explore the sensitivity of the method to the relative strengths of each pair.