Electron-ion spatiotemporal relaxation behavior of laser heated iron nano-foil studied by time resolved XANES and ab-initio simulations*

Thermophysical properties such as specific heat, electron-phonon coupling, thermal conductivity under electron-ion non-equilibrium condition in warm dense matter regime (T ~ a few eV) are largely unknown mainly because of the lack of well-established experimental methods. In recent years, significant progresses have been made in both theoretical and experimental techniques that allow us to access to such information. In this presentation, we will discuss an experiment using time resolved XANES that allows us to extract sufficient information for constraining the thermophysical properties of our interest, where ab-initio derived two-temperature model is used to simulate the spatiotemporal electron-ion relaxation behavior of nano-meter thin iron foil that is exposed to femto second laser pulse, which in turn is used to simulate temporal behavior of XANES spectrum. Importance of the choices of geometrical design of target as well as corresponding laser fluece will also be discussed in detail.