Three-Dimensional Simulations of Laser–Plasma Interactions at Ultrahigh Intensities

Three-dimensional particle-in-cell simulations are used to investigate the interaction of ultrahigh-intensity lasers (>;10²⁰ W/cm^-2) with matter at overcritical densities. Intense laser pulses are shown to penetrate up to relativistic critical density levels and to be strongly self-focused during this process. The heat flux of the accelerated electrons is observed to have an annular structure when the laser is tightly focused, showing that a large fraction of fast electrons is accelerated at an angle. These results shed light into the multidimensional effects present in laser-plasma interactions of relevance to fast ignition of fusion targets and laser-driven ion acceleration in plasmas.