Kinetics of x-ray lasing by resonant photoexcitation: Fundamentals of pumping power and gain for the Na x-Ne ix system

Two of the most fundamental aspects of the sodium-neon resonantly photopumped x-ray laser system are examined: the functional dependencies of the sodium-plasma pumping-line power output and the atomic-level kinetics in the neon which determine gain. For sodium, the growth of pumping power with size, temperature, and density of the plasma is quantified with numerical and analytic calculations. In the neon an analytic model of the gain kinetics is developed which allows quantitative assessments of the effects of each important rate and process on the gain. Both analytic models should be applicable to similar resonantly pumped systems by using the appropriate rates for those systems. In addition, a novel way of depleting the lower lasing state in an optically thick laser medium is presented.