LASER WAKEFIELD ACCELERATION WITH HIGH BEAM QUALITY

摘要

The dynamics of accelerated electrons in channel-guided LWFA is studied analytically and numerically with particular attention to beam quality. From the existence of adiabatic invariants for transverse motion, we deduce that the electron bunch is focused during the acceleration. This focusing strongly reduces the influence of transverse dynamics on final energy spread and makes it possible to apply a strategy of optimal phasing originally developed for one-dimensional acceleration. Using a particle code that combines linear hydrodynamic equations for the laser wakefield in the plasma channel and particle-in-cell methods for description of the electron bunch and its collective self-interactions, we have demonstrated that it is possible to produce a low-energy spread, low-emittance beam in a high beam loading regime.