Calculations of a high-gain recombination x-ray laser at 4.55 nm

Detailed theoretical investigations of a hydrogenlike magnesium recombination laser at 4.55 nm (the n=3→2 Balmer α transition) produced by psec and sub-psec laser pulses irradiating fiber targets are presented. Shorter pulses are shown to produce larger x-ray laser gain with less pumping laser energy.