Particle-in-cell simulations of Raman forward scattering from short-pulse high-intensity lasers

We present one- and two-dimensional particle-in-cell simulations of short-pulse (τ<1 ps) high-intensity (I≤10¹⁸ W/cm²) laser propagation through an underdense plasma. The simulations model near-term experiments without the limitations of the fluid and quasistatic approximations. We find that Raman forward scattering plays a dominant role in the evolution of the pulse in distances less than a Rayleigh length. Raman forward scattering results in significant spectral cascading and energetic electron generation from wave breaking of the resulting plasma wave. Both of these effects should be useful as experimental diagnostics.