Acceleration of electrons to the 100 GeV range in laser wakefield accelerators using multi-petawatt lasers is numerically modelled. It is demonstrated that an externally injected electron bunch with an initial energy of 50 MeV can achieve an energy gain of 100 GeV in the weakly non-linear regime of laser wakefield acceleration. The guiding of the laser is achieved by a plasma channel having a parabolic radial density profile. A comparative study of plasma channels (matched and unmatched) is performed to investigate the sensitivity of electron acceleration to the matching condition in this regime. It is found that unmatched channels restrict energy gain to ∼60 GeV and lead to radial loss of injected charge due to the oscillation of the spot size of the laser inside the channels.
Laser particle acceleration: beat-wave and wakefield experiments