On the Properties of Plastic Ablators in Laser-Driven Material Dynamics Experiments

TL;DR

This study uses radiation hydrodynamics simulations to analyze how plastic ablators influence laser-driven shock experiments, revealing sensitivities to composition, the importance of irradiance control, and relationships between laser parameters and pressure profiles.

Contribution

It provides new algebraic relations linking laser pulse duration, ablator thickness, and pressure duration based on shock dynamics and equations of state.

Findings

Ablation pressure sensitivity to composition and EOS is 5-10%.

Adjusting irradiance history stabilizes pressure output.

Impedance mismatch significantly increases transmitted pressure.

Abstract

Radiation hydrodynamics simulations were used to study the effect of plastic ablators in laser-driven shock experiments. The sensitivity to composition and equation of state was found to be 5-10% in ablation pressure. As was found for metals, a laser pulse of constant irradiance gave a pressure history which decreased by several percent per nanosecond. The pressure history could be made more constant by adjusting the irradiance history. The impedance mismatch with the sample gave an increase o(100%) in the pressure transmitted into the sample, for a reduction of several tens of percent in the duration of the peak load applied to the sample, and structured the release history by adding a release step to a pressure close to the ablation pressure. Algebraic relations were found between the laser pulse duration, the ablator thickness, and the duration of the peak pressure applied to the sample, involving quantities calculated from the equations of state of the ablator and sample using shock dynamics.