PPPS-2013: Importance of laser rise-time on relativistic electron dynamics in dense targets

We report on experiment with the Z-Petawatt laser at Sandia National Laboratories and with the Trident laser at Los Alamos National Laboratory using mm-sized foils and mass-limited targets of various thicknesses. Rear side accelerated proton beam measurements, in combination with simulation results, were used to infer hot electron transport in presence of preplasma. Full-scale, 3D radiation-hydrodynamics simulations of the ns to ps prepulse were performed. Preplasma properties (density profiles, temperatures, charge states) and laser pulse parameters (ps temporal pulse shape, focal spot size, energy, etc) were then imported into a fully explicit and kinetic 2D particle-in-cell code to simulate >10 ps of the main laser pulse interaction with the preplasma and target at full scale. A comparison of experimental data and numerical data shows outstanding agreement in all measured proton beam parameters and K-alpha x-ray yield, and gives confidence in the simulation results of hot electron transport.