Surface plasmon-driven electron and proton acceleration without grating coupling

Surface plasmon (SP) excitation in intense laser interaction with solid target can be exploited for enhancing secondary emissions, particular efficient acceleration of high charge electron bunches. Previous studies have mostly used grating coupling to allow SP excitation, which requires stringent contrast conditions preserve the structural integrity target. Here we show via simulations that currently available short pulse lasers occur a flat foil irradiated at parallel or grazing incidence ($\sim 5^\circ$ surface) without surface modulation. In turn, accelerated electrons effective generating proton beams narrow spectra peaked $>$100 MeV energies drivers.