Hydrodynamic instability growth of the fuel–ablator interface induced by rippled rarefaction waves in inertial confinement fusion implosion experiments

Hydrodynamic instability growth at the deuterium–tritium (DT) fuel–ablator interface plays a critical role in determining the performance of inertial confinement fusion implosions. During the late stages of implosion, insufficient doping of the ablator material can result in high-energy X-ray preheat, which may trigger the development of a classical-like Rayleigh–Taylor instability (RTI) at the fuel–ablator interface. In implosion experiments at the Shenguang 100 kJ-level laser facility, the primary source of perturbation is the roughness of the inner DT ice interface. In this study, we propose an analytical model to describe the feed-out process of the initial roughness of the inner DT ice interface. The perturbation amplitude derived from this model serves as the initial seed for the late-time RTI during the acceleration phase. Our findings confirm the presence of classical-like RTI at the fuel–ablator interface. Numerical simulations conducted using a radiation hydrodynamic code validate the proposed analytical model and demonstrate the existence of a peak mode number in both the feed-out process and the classical-like RTI. It provides an alternative bridge between the current target fabrication limitations and the unexpected implosion performance.