Multi-GeV electron bunches from an all-optical laser wakefield accelerator

• Main Authors: Miao, B, Shrock, J. E, Feder, L, Hollinger, R. C, Morrison, J, Nedbailo, R, Picksley, A, Song, H, Wang, S, Rocca, J. J, Milchberg, H. M
• Format: Journal Article
• Language: English
• Published: 06.12.2021
• Subjects: Physics - Accelerator Physics; Physics - Optics; Physics - Plasma Physics
• DOI: 10.48550/arxiv.2112.03489

We present the first demonstration of multi-GeV laser wakefield acceleration in a fully optically formed plasma waveguide, with an acceleration gradient as high as 25 GeV/m. The guide was formed via self-waveguiding of <15 J, 45 fs (<~300 TW) pulses over 20 cm in a low density hydrogen gas jet, with accelerated electron bunches simultaneously driven up to 5 GeV in a milliradian divergence quasi-monoenergetic peak of relative energy width ~15% and charge of at least ~10 picocoulombs. Energy gain is inversely correlated with on-axis waveguide density in the range N_e0=(1.3-3.2)x10^17 cm^(-3). We find that shot-to-shot stability of bunch spectra and charge are strongly dependent on the pointing of the injected laser pulse and gas jet uniformity. We also observe evidence of pump depletion-induced dephasing, a consequence of the long optical guiding distance.