Heating in multi-layer targets at ultra-high intensity laser irradiation and the impact of density oscillation

We present a computational study of isochoric heating in multi-layered (ML) targets at ultra-high intensity laser irradiation (similar to 10(20) W cm(-2)). Previous studies have shown enhanced ion heating at interfaces, but at the cost of large temperature gradients. Here, we study ML targets to spread this enhanced interface heating to the entirety of the target and find heating parameters at which the temperature distribution is more homogeneous than at a single interface while still exceeding the mean temperature of a non-layered target. Further, we identify a limiting process of pressure oscillations that causes the layers to alternate between expanding and being compressed and leads to lower ion temperatures. Based on that, we derive an analytical model estimating the oscillation period to find target conditions that optimize heating and temperature homogeneity. This model can also be used to infer the electron energy from the oscillation period which can be measured e.g. by XFEL probing.

Automated summary

This paper presents a computational study on isochoric heating in multi-layered targets under ultra-high intensity laser irradiation. The study finds that spreading the enhanced interface heating to the entirety of the target can result in a more homogeneous temperature distribution, exceeding the mean temperature of a non-layered target. An analytical model is derived to estimate the oscillation period, which can optimize heating and temperature homogeneity. The model can also infer the electron energy.