Temporal and far-field characterisation of the transient Ni-like Ag X-ray laser under traveling-wave irradiation

This paper summarises our recent progress achieved in the characterisation and understanding of the Ni-like Ag transient X-ray laser pumped under traveling wave irradiation. At the Rutherford Laboratory CPA laser facility, we measured the temporal history of the 13.9 nm laser pulse with a high-resolution streak camera. A very short, ∼2 ps X-ray laser pulse was directly demonstrated for the first time. More recently we carried out an experiment at the LULI CPA laser facility. Several diagnostics that recorded the plasma emission at the XRL wavelength or in the keV range indicate the presence of small-scale spatial structures in the emitting XRL source. Single-shot Fresnel interferograms at 13.9 nm were successfully obtained with a good fringe visibility. Strong lasing was also observed on the Ni-like 4f-4d line at 16 nm.