A method to achieve rapid localised deep heating in a laser irradiated solid density target

TL;DR

This paper introduces a novel resistive guiding target design that concentrates laser-generated fast electrons at specific depths, enabling rapid and localized deep heating of solid density targets for applications like XUV sources and shock experiments.

Contribution

The paper presents a new target design using principles of non-imaging optics to achieve deep localized heating by guiding fast electrons, improving upon previous non-structured target methods.

Findings

Global temperature maximum at 50 μm depth achieved

Large angular spread reduces electron confinement efficiency

Optimal laser intensity identified for maximum heating ratio

Abstract

Rapid heating of small buried regions by laser generated fast electrons may be useful for applications such as XUV radiation sources or as drivers for shock experiments. In non-structured targets the heating profile possesses a global maximum near the front surface. This paper presents a new target design that uses resistive guiding to concentrate the fast electron current density at a finite depth inside the target. The choice of geometry uses principles of non-imaging optics. A global temperature maximum at depths up to 50{\mu}m into the target is achieved. Although theoretical calculations suggest that small source sizes should perform better than large ones, simulations show that a large angular spread at high intensities results in significant losses of the fast electrons to the sides. A systematic parameter scan suggests an optimal laser intensity. A ratio of 1.6 is demonstrated between the maximum ion temperature and the ion temperature at the front surface.