Passive freeze-out of the Richtmyer-Meshkov instability

TL;DR

This paper demonstrates a novel passive method to suppress the Richtmyer-Meshkov instability in inertial confinement fusion using additively manufactured voids, achieving over 70% suppression without changing the driving pulse.

Contribution

First experimental demonstration of passive freeze-out of RMI via temporal shaping using engineered voids, offering a new pathway for instability control in ICF.

Findings

Over 70% suppression of RMI upstream of the surface.

Passive suppression achieved without modifying the pressure pulse or surface geometry.

Temporal shaping is the primary mechanism for instability suppression.

Abstract

The Richtmyer-Meshkov instability (RMI) poses a major challenge in inertial confinement fusion (ICF) due to its role in mixing and performance degradation. We report the first experimental observation of passive freeze-out of RMI in a low-pressure surrogate regime; an instability stagnation effect induced without modifying the driving pressure pulse or the target surface geometry. Using additively manufactured sub-surface voids in a sinusoidal target, we convert a single shock into a sequence of weaker shocks that suppress instability growth upstream of the surface by over 70%. High-speed X-ray imaging and hydrodynamic simulations suggest that this suppression arises primarily from temporal shaping, with lesser contributions from spatial curvature and shock weakening. Our results demonstrate a driver-independent pathway for controlling shock-driven hydrodynamic instabilities relevant to ICF and other high energy density systems.