Dynamics of femtosecond heated warm dense copper with time-resolved L3-edge XANES

Abstract

Combining experimental set up and ab initio molecular dynamics simulations, we were able to follow the time evolution of the X-ray absorption near edge spectrum (XANES) of a dense copper plasma. This provides a deep insight into femtosecond laser interaction with a metallic copper target. This paper presents a review of the experimental developments we made to reduce the X-ray probe duration, from approximately 10 ps to fs duration with table-top laser systems. Moreover, we present microscopic scale simulations, performed with Density Functional Theory, as well as macroscopic simulations considering the Two-Temperature Model. These tools allow us to get a complete picture of the evolution of the target at a microscopic level, from the heating process to the melting and expansion stages, with a clear view of the physics involved during these processes. This article is part of the theme issue ‘Dynamic and transient processes in warm dense matter’.

Dynamic and transient processes in warm dense matter

“…Interest in the issue of electron–ion equilibration is further motivated by the fact that short-pulse laser systems have also been used to extend WDM experiments to the other end of the temporal scale, for example, Lecherbourg et al [ 46 ] will present results on the evolution of solid copper into a warm dense matter state, in this case, after excitation with a femtosecond laser pulse. More recently, and of particular significance to the work in this issue, the advent of X-ray free-electron lasers has made it possible to achieve volumetric heating on sub-picosecond timescales [ 45 , 47 ].…”