Bright x-ray radiation from plasma bubbles in an evolving laser wakefield accelerator

Abstract

We show that the properties of the electron beam and bright x rays produced by a laser wakefield accelerator can be predicted if the distance over which the laser self-focuses and compresses prior to self-injection is taken into account. A model based on oscillations of the beam inside a plasma bubble shows that performance is optimized when the plasma length is matched to the laser depletion length. With a 200 TW laser pulse, this results in an x-ray beam with a median photon energy of 20 keV, > 6 × 10 8 photons above 1 keV per shot, and a peak brightness of 3 × 10 22 photons s − 1 mra d − 2 mm − 2 ( 0.1 % BW ) − 1 .