On laser wakefield acceleration in plasma channels

The structure of the laser wakefield is analyzed for wide and narrow (in comparison with plasma wavelength) plasma channels with parabolic in radial direction plasma density distributions. The results of analytical theory are confirmed by the self-consistent nonlinear numerical modeling of laser pulse propagation and wakefield generation. In narrow plasma channels the accelerating longitudinal component of the wakefield decreases rapidly with the distance from a laser pulse. This makes possible a short single electron bunch acceleration even if the injected electron beam is much longer than a plasma wavelength.