X-ray emission from laser-heated spherical plasmas

A model was developed for calculating x-ray line emission from spherical plasmas. The main features of this method are: (1) Plasma parameters are obtained from a one-dimensional Lagrangian hydrodynamics and heat-flow code. (2) Multi-frequency groups: the line structure can be reproduced with the desired accuracy by adjusting the number of frequency groups. (3) Self consistent, time dependent excited level populations and radiation fluxes: the code starts with coronal populations, calculates the ensuing radiation flux, and then recalculates the populations and so on, iterating until convergence is reached. (4) Geometrical groups of ray groups by spherical impact parameters. (5) Line broadening due to ionic thermal agitation and Doppler shift due to the net plasma flow velocity. Inclusion of the flow velocity shift would be different without the multi-frequency group treatment. The method was applied to an aluminum target, and the results are in good agreement with previous experimental work. The total energy, summed over all lines, as well as the line intensity ratios (which are a sensitive measure of agreement with experiment) were predicted with good accuracy. The pictures that would be seen by a pinhole camera are also calculated by the code