Simulation of recombination-pumped soft-x-ray lasers in wall-confined laser-produced plasmas

We describe the physical mechanisms of the recombination-pumped laser action of the carbon vi Balmer-α line (18.2 nm), which is expected to have a gain duration of as long as 10 nsec in the cylindrical-wall-confinement plasmas produced by a CO2 laser. We present the modeling of the laser action with the combination of the one-dimensional hydrodynamic code and the multilevel atomic rate equation code. The gain coefficient derived from the calculated dynamics of the level populations is somewhat smaller than the experimental data. Additional expansion cooling may account for the discrepancy. The higher gain coefficient of the order of 5 cm−1 is expected when we irradiate a high-Z doped cylinder-type target.