Imaging Electron Trajectories in a Laser-Wakefield Cavity Using Betatron X-Ray Radiation

Abstract

We demonstrate that betatron x-ray radiation accurately provides direct imaging of electrons trajectories accelerated in laser wakefields. Experimental far field x-ray beam profiles reveal that electrons can follow similar transverse trajectories with typical excursions of $1.5\mu \mathrm{m}\pm 0.5\mu \mathrm{m}$ in the plane of laser polarization and $0.7\mu \mathrm{m}\pm 0.2\mu \mathrm{m}$ in the plane perpendicular.