Scaling of neonlike lasers using exploding foil targets

We present a set of calculations for laser-gain predictions in a neonlike collisional excitation scheme using laser-driven exploding foil targets. The calculation includes three steps: the ionization balance, the neonlike excited-state kinetics, and the hydrodynamics of the exploding foil target. The ionization-balance model solves steady-state rate equations, including excited states, using scaled hydrogenic atomic physics. The model for the neonlike excited-state kinetics is also steady state and includes the ground state and the 36 n = 3 excited states, with radiative and collisional transitions connecting these states. The plasma conditions in the exploding foil targets are calculated by using the similarity model of London and Rosen [ Phys. Fluids29, 3813 ( 1986)]. For selected elements in the range 20 < Z < 56, we predict the gain for the two most prominent 2p53p to 2p53s (J = 2–1) transitions seen in experiments, the plasma conditions necessary to maximize the gain, and the specifications for the laser driver and target required to reach those plasma conditions. Our predicted gains are larger than those measured in experiments, for reasons we discuss, but our calculations agree qualitatively with the observed trends; the gain peaks for elements around selenium and falls off for both lighter and heavier ions. Neglected effects, such as time-dependent kinetics and radiation trapping, are also discussed.