Analysis of a possible laser at 230 Å in Be-like MgIX, resonantly photoexcited by the 48.338 Å line of AlXI

Summary form only given. An analysis of the MgIX laser at 230 Å, resonantly photoexcited by the 48.338-Å line of AlXI, was performed. The AlXI pump line could be produced by an imploding plasma z-pinch. The MgIX lasant could be produced adjacent to the z-pinch by a line-focused. ~3-J/3-ns pulsed glass laser. For a 2-cm separation between the Al z-pinch and the Mg lasant, a simple model predicts a gain of 1 cm^-1 at 230 Å. when the AlXI pump line radiates 1 GW and the lasant conditions are optimal. An analysis of the expected power in the AlXI, 48.338-Å line in an optimized z-pinch yields an estimated maximum pump line power density of ≈100 GW/cm³, which, for a typical z-pinch 2.5 mm in diameter and 3-4 cm in length, gives a line power of 15-20 GW. Analysis of Al line spectra obtained from 3.5-MA implosions on the ≈5-TW DNA/Double-EAGLE generator gives a measured 48.338-Å line power >2.5 GW. These 3.5-MA implosions were optimized for Al K-shell X-ray yield, rather than for the AlXI lines. A lower-current, lower-temperature, optimized z-pinch might therefore produce line powers at 48.338-Å that approach the theoretical estimates of 15-20 GW. Since the line power required for unity gain is only ≈1 GW, a very-high-gain laser at 230 Å is thus possible, using an ≈1-TW pulsed power driver