Figure 6
From: High-charge electron beams from a laser-wakefield accelerator driven by a CO2 laser
(a) Mean energy and (b) charge of electron beams produced in a pre-ionised plasma of varying density by a laser pulse with duration of 500 fs (FWHM), energy of 100 J, wavelength of \({10.6}\,\upmu \hbox {m}\) and varying waist size. Vertical lines mark the plasma wavelength \(\lambda _p\). Error bars correspond to the r.m.s. energy spread.
