Intense electron and proton beams from PetaWatt laser–matter interactions

Recent experiments at the LLNL Petawatt Laser have demonstrated the generation of intense, high-energy beams of electrons and ions from the interaction of ultra-intense laser light with solid targets. The focused laser intensities are as high as 6×1020 W/cm2, at which point the quiver energies of the target electrons extend to ∼10 MeV. In this new, fully relativistic regime of laser–plasma interactions, nuclear processes become important and nuclear techniques are required to diagnose the high-energy particle production. We describe recent experiments in which we have observed electrons accelerated to 100 MeV, photo-nuclear fission, positron–electron pair creation, monoenergetic electron jets and intense beams of protons emitted from the back surface of a laser-irradiated target.