Plasma waveguide control of low divergence, high charge multi-GeV electron beams*

The first demonstrations of fully optical multi-GeV laser wakefield acceleration (LWFA) have been enabled by the advent of low density (~10¹⁷ cm^-3), meter-scale plasma waveguides generated in supersonic gas jets [1-7]. I will present recent experiments and a new propagation model [5,6] demonstrating how control of plasma waveguide properties leads to multi-GeV electron bunches with nC-level charge and sub-milliradian divergence. Specifically, I will discuss experimental data from a scan of the plasma waveguide matched mode waist radius and corresponding simulations to illustrate how beam propagation in each channel results in control over electron beam charge, energy, divergence, energy spread, and beam profile. Finally, I will share demonstrations of custom waveguide features including tailored plasma waveguides to improve coupling and counteract dephasing.