Figure 2.

Kinetic electron temperature (a) and transient electron–ion collision time (b) as a function of time. The deposited dose was 1.2 MJ kg⁻¹. The maximum of the FEL pulse intensity is at t = 0 fs. The X-ray photon energy was 245 eV and the FWHM pulse duration of 60 fs. The peak X-ray intensity at time zero was 2.5 × 10¹² W cm⁻².