Pulse Compression in Staged Laser Wakefield Acceleration*

Laser Wakefield Acceleration (LWFA) enables orders of magnitude higher acceleration gradients than a conventional electron accelerator. We present numerical studies of a two stage LWFA. In particular, we studied the impact of a high density gas stage as a pulse compressor and electron injector, followed by a lower density acceleration stage. 2.5D Particle In Cell simulations of the laser evolution and the wakefield were performed in WarpX. Simulations were performed to understand the influence of the density profile, stage transition, and pulse evolution on the injection of electrons into the bubble.