Fig. 4: Simulated electron bunch propagation and energy spectra.
From: Unforeseen advantage of looser focusing in vacuum laser acceleration
Simulated electron distribution from all angles: a Side view of f#1 case, with laser electric field plotted over the electron density in (x-y) space, b top view of the same in (x-z) space. Each individual electron bunch is labelled from A to D and the shaded gray line marks one Rayleigh length (ZR) from the focus at nanotip (where the solid yellow lines cross). c Total moving electron density in (y-z) space, plotted over the average laser intensity. d Energy distribution of individual electron bunches. All the panels are plotted at 16t0 when all electron bunches have already crossed a Rayleigh length.
