Modeling of the saturated Ni-like silver x-ray laser

This paper reports on the modeling of the Ni-like silver transient x-ray laser at the wavelength of 13.9 nm. Time-dependent populations and gain are calculated consistently with the output intensity. Two-dimensional refraction, i.e., in the direction of the driving laser and parallel to the slab target surface, is modeled by a ray trace code which is a postprocessor of a hydrodynamic code. Temperatures and electron-density variations are given by the hydrocode. Our calculations show that interaction of the x-ray laser field with the amplifying medium, and refraction, affect the output intensity and reduce the gain values by a large factor: from many hundreds per cm, as predicted by collisional-radiative models ignoring the above interaction, to one hundred per cm, at most.