Propagation of chirped laser pulses in plasmas

Summary form only given, as follows. The propagation of chirped laser pulses in plasmas is analyzed and examined using 3D numerical simulations. Simulations are based on solving coupled fluid equations for the laser pulse envelope and wakefield which include the effects of group velocity dispersion and self-phase modulation in the weakly relativistic regime. The simulations can describe the relativistic modulation instability, forward Raman scattering, and self-modulation. The effects of chirp on these various instabilities are investigated. Results indicate that a frequency chirp, regardless of sign, can suppress the forward Raman instability. However, the modulation of the pump wave, the locations of the Stokes and anti-Stokes sidebands and the width of the sidebands are found to depend upon the sign of the chirp.