Simulation of the interaction of intense ultrashort X-ray laser pulses with micro-sized Al targets

Abstract

We study the interaction of extremely short and high-intensity X-ray pulses with a 1.0μm thick Al foil. Four pulse lengths – 100 fs, 200 fs, 300 fs, and 400 fs – are considered. The photon energy is 1830 eV and the pulse intensity is 1017W/cm2. The interaction dynamics are calculated via a radiation hydrodynamic code. The X-ray laser pulse heats the target isochorically. It generates a homogeneous hot dense matter; electrons are hotter than ions. The simulation of the interaction of pump and probe pulses with a delay time in the fs scale provides that the probe pulse heats the target significantly. A Monte-Carlo method is used to provide a microscopic description; the electron distribution function shows a two-temperature system. The electron distribution has spikes at the energy difference between the k-edges of Al ions and the energy of incident photons. The energies of these spikes depend on the considered ionization depression model. The Chihara formula and the non-equilibrium random phase approximation are utilized to calculate the X-ray Thomson scattering spectrum (XRTS). For collective scattering, the plasmon peaks are a function of the pulse lengths and the electron distribution function. Therefore, when XRTS is fitted to a measured spectrum may give the target density, the target temperature, and the microscopic electron distribution function.