Effects of ablation and mode coupling on the deeply nonlinear stages of the Rayleigh-Taylor instability

The Rayleigh-Taylor Instability (RTI) can be found at the interface of a light fluid pushing against a heavy fluid, causing any surface perturbations to grow exponentially in time. It occurs at all scales of the universe and is one of the canonical hydrodynamic instabilities leading to turbulence. Despite its prevalence, a great deal of uncertainty still surrounds its nonlinear stage of evolution. A recent experiment at the National Ignition Facility (NIF) explored the ablative form of this phenomenon and demonstrated that its nonlinear development is strongly influenced by the interface’s initial conditions [1]. However, while this behavior is well explained by recent theoretical work at the early stages of nonlinearity [2], its latest-time behavior deviates significantly from expectations. To address this, a new experiment has been designed at the NIF both to examine the cause of this disagreement and to explore the role of ablation in the system’s overall development. The first day of shots is scheduled for October 2021 and will provide valuable insights into the dynamic interplay of multimode bubble evolution.

[1] L. Ceurvorst et al, High Energy Density Physics 37, 100851 (2020).

[2] H. Zhang et al, Physical Review Letters 121, 185002 (2018).