Frequency redistribution effect on emissivity and intensity of Ge22+ and C5+ X-ray lasers

This work concerns the effect of frequency redistribution on X-ray laser be ams. The redistribution function, calculated by extending the frequency flu ctuation model to 2-photon processes, shows coherent scattering and a redis tributed contribution. The spectral emissivity, corrected in order to accou nt for this effect, is calculated for X-ray lasers, the amplifier plasma be ing composed either of neon-like germanium ions or hydrogen-like carbon ion s. The coupled radiative transfer equation and population equations are sol ved consistently, and the intensity of the X-ray laser output is given for two 3p-3s lines (19.6 and 23.6 nm) of neon-like germanium. We also study th e variation with plasma length (i.e. line intensity) of the emissivity of t he C5+ Balmer-a lasing line. The physical conditions of the calculations ar e obtained from a modelling of experiments conducted at the Rutherford Appl eton Laboratory.