Fig. 2: Intensity effects on 1D X-ray spectra.
From: Above-threshold ionization with X-ray free-electron lasers
Results of strong-field ionization by X-ray drivers at 125 eV (a–c) and at 250 eV (d–f). Panels a and d indicate the total ionization rate w (blue line). Panels b, e and c, f give partial rates into each ATI peak as a heat map, where b, e is on a log scale and c, f is on a linear scale. Additional dashed black lines indicate w ∝ I scaling in a, d and εk ∝ Up scaling in b, e. Vertical lines are included for intensity parameters at \({{{\mathcal{Z}}}}=0.1\) (light blue) and \({{{{\mathcal{Z}}}}}_{1}=0.1\) (green). The vertical pink line labeled T1/2 = 50 as corresponds to a limit where 50% of the ground-state is depleted after 50 as. For 125 eV this curve is located behind the \({{{{\mathcal{Z}}}}}_{1}=0.1\) mark.
