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