Generation of High Brightness Electron Beams via Ionization Induced Injection by Transverse Colliding Lasers in a Beam-Driven Plasma Wakefield Accelerator

摘要

The production of ultra-bright electron bunches using ionization injectiontriggered by two transversely colliding laser pulses inside a beam-drivenplasma wake is examined via three-dimensional (3D) particle-in-cell (PIC)simulations. The relatively low intensity lasers are polarized along the wakeaxis and overlap with the wake for a very short time. The result is that theresidual momentum of the ionized electrons in the transverse plane of the wakeis much reduced and the injection is localized along the propagation axis ofthe wake. This minimizes both the initial 'thermal' emittance and the emittancegrowth due to transverse phase mixing. 3D PIC simulations show that ultra-short(around 8 fs) high-current (0.4 kA) electron bunches with a normalizedemittance of 8.5 and 6 nm in the two planes respectively and a brightnessgreater than 1.7*10e19 A rad-2 m-2 can be obtained for realistic parameters.