Increasing Energy Gain in Laser Wakefield Accelerators using Direct Laser Acceleration*

Laser wakefield acceleration (LWFA) in the blowout regime is a means to produce high-energy (greater than 1 GeV), monoenergetic electron bunches [1]. However, LWFA operating outside of the ideal nonlinear blowout regime parameters can have Direct Laser Acceleration (DLA) as an additional acceleration mechanism. This study examines electron spectra produced by a LWFA operating outside of the ideal blowout regime and therefore expected to have a DLA contribution to the total energy gain of the produced electron bunch. OSIRIS particle-in-cell simulations of the experiment confirm the presence of DLA leading to total electron energies greater than the energy gain due to the wake acceleration alone. \\[4pt] [1] W.Lu et al., PRSTAB 10, 061301 (2007)