X-ray line emission from laser-produced spherical plasma flows

A numerical model has been developed for calculating x-ray line emission from spherical plasma flows and has been applied to a laser-heated, ablating aluminum target. The results are in good agreement with previous experimental work. The intensity ratios of the dominant lines are predicted in good agreement with experiment. A novel effect, not yet observed, is predicted in the interaction of nearby lines, here an Hα doublet: through Doppler shift caused by plasma flow one line absorbs the other. This line obscuring effect has potential applications to diagnosing details of ablative flows in x-ray lasing and inertial confinement fusion experiments. The main features of the model are plasma parameters obtained through a Lagrangian hydrodynamics model, radiative transport by multienergy and multi-impact parameter ray groups, and self-consistent, time-dependent computation of ion and ion energy-level populations. Approximately 100 energy groups per line resolve line structure and show Doppler effects. The scalings involved in extending this work to other plasma conditions and materials are discussed. © 1989 American Institute of Physics.