Parameter study of acceleration of externally injected electrons in the linear laser wakefield regime

A parameter study for laser wakefield acceleration is presented, in which externally injected electrons are accelerated in low amplitude plasma waves, represented by an analytical two-dimensional description. Results have been obtained for plasma densities up to 2.6×1024 m-3, plasma lengths up to 300 mm, laser intensities up to 3.5×1021 W/m2, and injection of Gaussian model bunches at energies up to 12 MeV. For the range of parameters studied, effects of laser depletion and the influence of the electron bunch on the plasma can be ignored. In the parameter space, a region is identified where final energies of over 100 MeV are reached, at an energy spread of less than 5% and a rms emittance of a few micrometers.