Fig. 4: Data with pump-probe delay Δt = 0.7 ns.
From: Recovery of hydrogen plasma at the sub-nanosecond timescale in a plasma-wakefield accelerator
a Mean energies for the spectra containing both the pump and probe (blue) and the two alone (red and yellow). The dashed green line shows the mean energies of the perturbed probe, obtained by subtracting to the pump and probe spectra the ones containing only the pump. The error bars are computed as the standard deviations of 20 consecutive shots. b Single-shot probe energy spectra with (red) and without (blue) the pump at initial plasma density np ≈ 1016 cm−3 (τD ≈ 1 μs, top) and np ≈ 1014 cm−3 (τD ≈ 4 μs, bottom). The dashed green line shows the probe spectrum with plasma turned off.
