Drop fragmentation by laser-pulse impact

TL;DR

This paper investigates how laser pulses cause liquid drops to fragment by analyzing the interplay of instabilities and deformation dynamics, revealing scaling laws and mechanisms behind ligament formation.

Contribution

It combines experimental data across different scales to identify Rayleigh--Taylor instabilities as key to laser-induced drop fragmentation and derives related scaling laws.

Findings

Rayleigh--Taylor instabilities drive fragmentation.

Scaling laws for breakup time and wavenumber are established.

Ligament web formation results from instability interplay and sheet thickness modulations.

Abstract

We study the fragmentation of a liquid drop that is hit by a laser pulse. The drop expands into a thin sheet that breaks by the radial expulsion of ligaments from its rim and the nucleation and growth of holes on the sheet. By combining experimental data from two liquid systems with vastly different time- and length scales we show how the early-time laser-matter interaction affects the late-time fragmentation. We identify two Rayleigh--Taylor instabilities of different origins as the prime cause of the fragmentation and derive scaling laws for the characteristic breakup time and wavenumber. The final web of ligaments results from a subtle interplay between these instabilities and deterministic modulations of the local sheet thickness, which originate from the drop deformation dynamics and spatial variations in the laser-beam profile.