Hot-electron generation from laser-pre-plasma interactions in cone-guided fast ignition

Two-dimensional particle-in-cell (PIC) simulations were performed for the cone-in-shell integrated fast-ignition experiments at the Omega Laser Facility [W. Theobald et al., Phys. Plasmas 18, 056305 (2011)]. The initial plasma density profile in the PIC simulations was taken from hydrodynamic simulations of the prepulse interaction with the gold cone. Hot-electron generation from laser-pre-plasma interactions and transport up to 100 x the critical density (n(c)) was studied. The simulation showed a mean divergence half-angle of 68 degrees and 50% absorption for the hot electrons. The simulation results show that the generated hot electrons were dominated in number by low-energy electrons but in energy by multi-MeV electrons. Electron transport between 5 and 100 nc was ballistic. In the late stage of the simulation, all the results were largely independent of polarization, indicating a stochastic hot-electron-generation mechanism. (C) 2013 AIP Publishing LLC.