Laser-Plasma-Based Generation of Ultra-Bright Electron Beams

Abstract

Laser-driven plasma-based accelerators are a compact method to accelerate electron beams, and accelerating gradients of 1–100 GV/m, several orders of magnitude larger than conventional accelerators, have been experimentally demonstrated. These high accelerating gradients combined with space charge shielding provided by the background plasma ions allow for the generation of high brightness electron beams. Plasma-based accelerators also naturally produce ultra-short beams, a fraction of the plasma wavelength. Controlled injection techniques, such as density gradient injection and laser-triggered injection, enable control over the electron beam production and phase space distribution. Two-color ionization injection, where one long-wavelength laser pulse generates a plasma wave for acceleration, and a second short-wavelength laser pulse is used to ionize and trap electrons, is capable of generating multi-kA electron beams with sub 100 nm normalized emittances. These laser-plasma-based methods of ultra-bright electron beam generation will be discussed, and progress toward experimental demonstration of two-color ionization injection will be reported.