Betatron oscillations of electrons accelerated in laser wakefields characterized by spectral x-ray analysis.

Relativistic electrons accelerated by laser wakefields can produce x-ray beams from their motion in plasma termed betatron oscillations. Detailed spectral characterization is presented in which the amplitude of the betatron oscillations r is studied by numerical analysis of electron and x-ray spectra measured simultaneously. We find that r reaches as low as 1 mum in agreement with previous studies of radiation based on coherence and far-field spatial profile.

Imaging electron trajectories in a laser-wakefield cavity using betatron X-ray radiation.

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 microm+/-0.