Probing ultrafast laser plasma processes inside solids with resonant small-angle X-ray scattering

TL;DR

This paper demonstrates the use of resonant small-angle X-ray scattering to probe ultrafast laser-induced plasma processes inside solids, revealing nanoscopic density, ionization, and temperature distributions in extreme states of matter.

Contribution

It introduces resonant SAXS as a novel method to characterize dynamic plasma processes in solids with femtosecond resolution.

Findings

Resonant SAXS can detect nanometer-scale density and temperature changes.

Heavy ion structures expand following heat diffusion at ultrahigh temperatures.

The technique provides insights into ultrafast plasma evolution in laboratory astrophysics.

Abstract

Extreme states of matter exist throughout the universe e.g. inside planetary cores, stars or astrophysical jets. Such conditions are generated in the laboratory in the interaction of powerful lasers with solids, and their evolution can be probed with femtosecond precision using ultra-short X-ray pulses to study laboratory astrophysics, laser-fusion research or compact particle acceleration. X-ray scattering (SAXS) patterns and their asymmetries occurring at X-ray energies of atomic bound-bound transitions contain information on the volumetric nanoscopic distribution of density, ionization and temperature. Buried heavy ion structures in high intensity laser irradiated solids expand on the nanometer scale following heat diffusion, and are heated to more than 2 million Kelvin. These experiments demonstrate resonant SAXS with the aim to better characterize dynamic processes in extreme laboratory plasmas.