Beat-wave excitation of plasma wave and observation of accelerated electrons.

The simultaneous observations of a beat-wave-excited plasma wave and of energetic electrons are reported. A plasma wave is excited when the beat-wave frequency of a laser with two wavelengths 10.6 and 9.57 μm equals the plasma frequency. The Stokes sideband measurement gives a wave amplitude δn/n 0 of ∼5%. Plasma electrons with the energies of more than 10 MeV are observed at the resonant density