The effect of electric wakefields (generated inside the pulse) on the propagation of a short, asymmetric laser pulse in a plasma channel is analyzed. A nonlinear wave equation governing the propagation dynamics of a moderately intense laser pulse in a plasma channel along with equations describing the generation of wakefields is set up. The simultaneous evolution describing the pulse length and spot size in the presence of wakefields is derived using a variational technique. Using numerical methods the evolution of spot size, pulse length and intensity is graphically analyzed. The frequency chirp induced due to the combined effects of group velocity dispersion and self-phase modulation is also obtained. A comparative study of the propagation characteristics of two pulses, one having a fast rise and slow fall time while the other with a slow rise and fast fall time, has been presented.
Effects of laser polarization and wavelength on hybrid laser wakefield and direct acceleration