Observed transition from Richtmyer-Meshkov jet formation through feedout oscillations to Rayleigh-Taylor instability in a laser target

TL;DR

This paper experimentally investigates the evolution of hydrodynamic instabilities in laser-driven targets, observing a transition from Richtmyer-Meshkov jets to Rayleigh-Taylor instability as shock pressure increases.

Contribution

It provides the first detailed experimental observation of the transition from Richtmyer-Meshkov to Rayleigh-Taylor instability in laser-irradiated targets at different shock pressures.

Findings

Planar jets form at sub-megabar pressures indicating Richtmyer-Meshkov instability.

At pressures above 1 Mbar, oscillatory expansion waves and feedout lead to Rayleigh-Taylor instability.

Target breakup occurs due to the development of Rayleigh-Taylor instability.

Abstract

Experimental study of hydrodynamic perturbation evolution triggered by a laser-driven shock wave breakout at the free rippled rear surface of a plastic target is reported. At sub-megabar shock pressure, planar jets manifesting the development of the Richtmyer-Meshkov-type instability in a non-accelerated target are observed. As the shock pressure exceeds 1 Mbar, an oscillatory rippled expansion wave is observed, followed by the "feedout" of the rear-surface perturbations to the ablation front and the development of the Rayleigh-Taylor instability, which breaks up the accelerated target.