The Effect of the Initial Density Profile on K-Shell Emission in Two-Dimensional Simulations of Argon Gas-Puff z Pinches

Summary form only given. In order to implode enough mass to the high specific energies necessary to produce K-shell emission from high Z elements like krypton, large-diameter Z-pinch loads will be required for short current rise time machines, like Z and ZR. For long pulse rise time machines, such as Decade Quad, large diameters are needed for the same reason and, in addition, they are needed to effectively couple the electrical energy that is delivered over a long current rise time to the load. The amount of K-shell emission produced from a large-diameter load has experimentally been shown to depend critically on the initial density distribution. In the work presented here, we investigate the initial gas-puff density distribution´s effect on the ability of the plasma to radiate in the K-shell. This study is performed using a modified version of the Air Force´s MACH2 magnetohydrodynamic code. The principal modification is the self-consistent addition of a state-of-the-art, computationally efficient, and reasonably accurate equation of state (EOS) and radiation transport model to MACH2. This EOS/radiation model is designed for modeling K-shell emitting plasmas and it is called the tabular collisional radiative equilibrium (TCRE) model. In this study comparisons are made between simulations of, and results obtained from, large-diameter load experiments on the Decade Quad and Double-EAGLE pulsed power generators.