Supernova-relevant hydrodynamic instability experiments on the Nova laser

Abstract

Observations of Supernova 1987A suggest that hydrodynamic instabilities play a critical role in the evolution of supernovae. To test the modeling of these instabilities, and to study instability issues which are difficult to model, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. We use the Nova laser to generate a 10–15 Mbar shock at the interface between an 85 μm thick layer of Cu and a 500 μm layer of CH2; our first target is planar. We impose a single mode sinusoidal material perturbation at the interface with λ=200 μm, η0=20 μm, causing perturbation growth by the RM instability as the shock accelerates the interface, and by RT instability as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few ×103 s. We use the supernova code PROMETHEUS and the hydrodynamics codes HYADES and CALE to model the experiment. We are designing further experiments to compare results for 2D vs. 3D single mode perturbations; high resolution 3D modeling requires prohibitive time and computing resources, but we can perform and study 3D experiments as easily as 2D experiments. Low resolution simulations suggest that the perturbations grow 50% faster in 3D than in 2D; such a difference may help explain the high observed velocities of radioactive core material in SN1987A. We present the results of the experiments and simulations.