Model calculations of extreme-ultraviolet gain in rapidly expanding cylindrical carbon plasmas

The development of gain by recombination on the 182-A H-α line of the hydrogenlike carbon for C vi is investigated theoretically. The plasma is produced by laser heating a thin carbon fiber. Quasi-analytic scaling laws are derived from earlier relations for expanding cylinders and for laser ablation from solid cylinders. The criterion for an ideal (optimal) gain mode is specified. Less stringent operating conditions are identified for a lower-gain, outer-zone mode of operation by means of a full hydrocode simulation.