Electron injection and emittance control by transverse colliding pulses in a laser-plasma accelerator

M Chen,D L Bruhwiler,S S Bulanov,E Cormier-Michel,W P Leemans,S Rykovanov,C G R Geddes,E Esarey,L L Yu,C Benedetti,C B Schroeder

doi:10.1103/physrevstab.17.051303

Abstract

A method to inject electron beams with controllable transverse emittances in a laser-plasma accelerators is proposed and analyzed. It uses two colliding laser pulses that propagate transversely to the plasma wave. For colliding pulses with equal frequencies, a beam with very low emittance is generated when the collision is close to the density peak of the plasma wave. Electrons near the axis are accelerated longitudinally by the ponderomotive force of the colliding pulses, accelerated transversely by the beat wave, and subsequently injected into the second bucket of the wake. Ionization is used to increase the transverse injection area and the final trapped charge. Simulations show that the transverse emittance can be less than the 0.1 mm mrad level, which is important for many applications. For colliding laser pulses with different frequencies, the beat wave can produce asymmetric injection, which can enhance betatron radiation generated by the electron beam.

Highlights

Laser-plasma acceleration (LPA), where an intense laser drives a plasma wave, is an active research field due to the ability of a plasma wave to sustain accelerating gradients much greater than conventional accelerators [1]
For colliding laser pulses with different frequencies, the beat wave can produce asymmetric injection, which can enhance betatron radiation generated by the electron beam
Reduction of the electron beam energy spread and transverse emittance is critical for many applications, and significant research has focused on controlled injection of electrons into the plasma wave to improve the electron beam quality [6,7,8,9,10,11,12,13,14,15,16,17,18,19]

Summary

Introduction

Laser-plasma acceleration (LPA), where an intense laser drives a plasma wave, is an active research field due to the ability of a plasma wave (wake) to sustain accelerating gradients much greater than conventional accelerators [1]. Electron injection and emittance control by transverse colliding pulses in a laser-plasma accelerator A method to inject electron beams with controllable transverse emittances in a laser-plasma accelerators is proposed and analyzed.

Results

Conclusion