K-shell Yield Performance Assessment of Argon Gas Puff Loads Imploded on Double-Eagle, Z, and Decade Quad

Abstract

The K‐shell yield performance of Titan double‐shell argon gas puff loads imploded on the Z machine and Decade Quad (DQ) is compared to the performance of Double‐Eagle loads employing the same nozzle configuration. Specifically, the K‐shell yields obtained on the Z and DQ machines are compared with I4, I2, and I0 current scaling projections made from Double‐Eagle yields, where I is the peak load current. This analysis allows initialization and multidimensional effects to be factored out of the scaling behavior. This projection analysis is useful for evaluating argon gas‐puff load performance because it relates I4, I2, and I0 K‐shell yield scaling transitions that a load, of a given specific energy, is predicted to undergo as the total load mass increases. Our analysis shows that the maximum K‐shell yields were near optimum for the nozzle configuration used and the energy coupled to the load in the Z and Decade Quad experiments. At present it is not understood why an additional 22 nH of inductance for DQ, 6 nH for the Z machine, and 8 nH for Double‐Eagle is required in their respective equivalent circuit models to reasonably match measured peak currents and implosion times. Note, we do not think that there is extra inductance in the real circuit; it is included in the modeled equivalent circuit as a method to account for the possible anomalous effects that are reducing the current from its expected value. These effects may include: multidimensional effects, current losses, and anomalous resistivity.