Growth rate and the cutoff wavelength of the Darrieus-Landau instability in laser ablation

TL;DR

This paper investigates the linear Darrieus-Landau instability in laser ablation flows, revealing it is significantly stronger and has a larger growth rate than in classical slow flames, with implications for experimental observation.

Contribution

It provides a numerical analysis of the dispersion relation for the instability in laser ablation, considering flow structure and specific laser ablation features.

Findings

Darrieus-Landau instability in laser ablation is much stronger than in classical flames.

Maximum growth rate in laser ablation is about three times larger.

Characteristic length scale is comparable to the distance from ablation to laser absorption zone.

Abstract

The main characteristics of the linear Darrieus-Landau instability in the laser ablation flow are investigated. The dispersion relation of the instability is found numerically as a solution to an eigenvalue stability problem, taking into account the continuous structure of the flow. The results are compared to the classical Darrieus-Landau instability of a usual slow flame. The difference between the two cases is due to the specific features of laser ablation: high plasma compression and strong temperature dependence of electron thermal conduction. It is demonstrated that the Darrieus-Landau instability in laser ablation is much stronger than in the classical case. In particular, the maximum growth rate in the case of laser ablation is about three times larger than that for slow flames. The characteristic length scale of the Darrieus-Landau instability in the ablation flow is comparable to the total distance from the ablation zone to the critical zone of laser light absorption. The possibility of experimental observations of the Darrieus-Landau instability in laser ablation is discussed.