Design principles for high quality electron beams via colliding pulses in laser plasma accelerators

Abstract

Laser plasma based accelerators have the potential to reduce dramatically the size and cost of future particle colliders and light sources. Production of high quality beams along with reproducibility, tunability, and efficiency are required for many applications. We present design principles for two-pulse colliding laser pulse injection mechanisms, which can meet these requirements. Simulations are used to determine the best conditions for the production of high quality beams: high charge, low energy spread, and low emittance. Simulations also allow access to the internal dynamics of the interaction, providing insight regarding further improvement of the beam quality. We find that a 20 pC beam can be accelerated to 300 MeV in 4 mm with only a few percent energy spread and transverse normalized emittance close to 1 mm mrad, using a 10 TW laser. We demonstrate that this design scales according to linear theory. Control of the laser pulse mode content and subsequent evolution in the plasma channel are shown to be critical for achieving the highest beam quality.