A possible scheme of electron beam bunching in laser plasma accelerators

A possible scheme for increasing the injection efficiency in laser plasma accelerators is proposed. It allows an improvement of both the number of captured electrons and the energy spread. The operation in linear regime is discussed. The plasma channel is divided into two stages: the modulating stage with a variable plasma density for pre-bunching the beam and the accelerating stage with a constant plasma density. The variation of the plasma density in the bunching stage and the matching between the stages are discussed.