Calculations of photoionization and photoexcitation of neon by X-rays from a sodium-bearing Z pinch imploded on Saturn

Summary form only given. In a recent series of experiments on Saturn (32 TW, 10 MA) at Sandia National Laboratories, a cylindrical neon gasbag was exposed to the ~300 kJ of X-rays emitted from sodium-bearing z-pinch plasmas. These experiments demonstrated that the neon was photoionized to, but not beyond, the heliumlike state and also provided considerable evidence for fluorescence of the Ne IX 1 s₂-1s4p ¹P₁ line by the well-known coincident 11-A Na X 1s²-1 s2p¹P₁ line. The authors have undertaken detailed modeling of the time-dependent behavior of the neon in these experiments using a full multifrequency radiative transfer algorithm coupled to one-dimensional cylindrical hydrodynamics. The evolution of the temperature, density, charge state, level populations, and gain was calculated as a function of time using the measured flux of pump X-rays. The dependencies of these properties on the hot-pinch/cold-gasbag separation were also determined. Neon calculations have also been performed using purely theoretical X-ray pump fluxes which may be accessible to Saturn. These latter simulations demonstrate how to optimize the gain with the proper combination of broadband ionizing flux and sodium pump line power