Spectroscopy and gain dynamics issues in inhomogeneous X-ray laser plasmas

Time- and two-dimensional spatially-resolved monochromatic imaging is performed on Ne-like germanium laser-produced line plasmas to study the behaviour of the inhomogeneities along the line created by a nonuniform irradiation. The imaging is done at the wavelengths of the 2s2p 6 3d-2s 2 2p 6 (J=2-0) E2 quadrupole line ( lambda =8.031 A) and the 2s2p 6 3p-2s 2 2p 6 (J=1-0) 3A dipole line ( lambda =8.371 A) which originate respectively from the upper and lower states of the core-excited 3d-3p X-ray laser line at 199 A. We compare the E2 and 3A results to LASNEX hydrodynamics and associated atomic physics, and investigate the problem of extracting the 3d-3p local gain dynamics along the inhomogeneous line plasma from spectroscopic imaging of the plasma. The effect of the irradiation uniformity conditions on the integrated lasing intensity is discussed.