Ion heating dynamics in solid buried layer targets irradiated by ultra-short intense laser pulses

TL;DR

This study uses particle-in-cell simulations to explore how ultra-short, high-intensity laser pulses heat ions in a layered solid target, revealing enhanced deuteron heating due to pressure-driven motion.

Contribution

It demonstrates the mechanism of ion heating enhancement in a layered target geometry under relativistic laser irradiation, highlighting the role of pressure gradients and collective motion.

Findings

Enhanced deuteron ion heating observed in the compressed layer.

Heating effects are detectable at laser pulses as short as 100 femtoseconds.

Potential for experimental probing with high repetition rate laser systems.

Abstract

We investigate bulk ion heating in solid buried layer targets irradiated by ultra-short laser pulses of relativistic intensities using particle-in-cell simulations. Our study focuses on a CD2-Al-CD2 sandwich target geometry. We find enhanced deuteron ion heating in a layer compressed by the expanding aluminium layer. A pressure gradient created at the Al-CD2 interface pushes this layer of deuteron ions towards the outer regions of the target. During its passage through the target, deuteron ions are constantly injected into this layer. Our simulations suggest that the directed collective outward motion of the layer is converted into thermal motion inside the layer, leading to deuteron temperatures higher than those found in the rest of the target. This enhanced heating can already be observed at laser pulse durations as low as 100 femtoseconds. Thus, detailed experimental surveys at repetition rates of several ten laser shots per minute are in reach at current high-power laser systems, which would allow for probing and optimizing the heating dynamics.