Generation and pointing stabilization of multi-GeV electron beams from a laser plasma accelerator driven in a pre-formed plasma waveguide

• Published in: Physics of plasmas 2015-05, Vol.22 (5)
• Main Authors: Gonsalves, A. J., Nakamura, K., Daniels, J., Mao, H.-S., Benedetti, C., Schroeder, C. B., Tóth, Cs, Tilborg, J. van, Vay, J.-L., Geddes, C. G. R., Esarey, E., Mittelberger, D. E., Bulanov, S. S., Leemans, W. P., Department of Physics, University of California, Berkeley, California 94720
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CAPILLARIES; ELECTRON BEAMS; FLUCTUATIONS; GEV RANGE; LASERS; PEAK LOAD; PLASMA DENSITY; PLASMA GUNS; PULSES; SIMULATION; STABILIZATION; WAVEGUIDES
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.4919278

Laser pulses with peak power 0.3 PW were used to generate electron beams with energy >4 GeV within a 9 cm-long capillary discharge waveguide operated with a plasma density of ≈7×10{sup 17} cm{sup −3}. Simulations showed that the super-Gaussian near-field laser profile that is typical of high-power femtosecond laser systems reduces the efficacy of guiding in parabolic plasma channels compared with the Gaussian laser pulses that are typically simulated. In the experiments, this was mitigated by increasing the plasma density and hence the contribution of self-guiding. This allowed for the generation of multi-GeV electron beams, but these had angular fluctuation ≳2 mrad rms. Mitigation of capillary damage and more accurate alignment allowed for stable beams to be produced with energy 2.7±0.1 GeV. The pointing fluctuation was 0.6 mrad rms, which was less than the beam divergence of ≲1 mrad full-width-half-maximum.