  We measure the emission of energetic electrons from the interaction between
ultrashort laser pulses and a solid density plasma in the relativistic regime.
We detect an electron beam that only appears with few-cycle pulses (< 10 fs)
and large plasma scale lengths ($L > \lambda_0$). Numerical simulations, in
agreement with the experiments, reveal that these electrons are accelerated by
a laser wakefield. Plasma waves are indeed resonantly excited by the few-cycle
laser pulses in the near-critical-density region of the plasma. Electrons are
then injected by ionization into the plasma waves and accelerated to
relativistic energies. This study provides an unprecedented insight into the
physics happening in the few-cycle regime.
