Exploring Ways to Improve Z-Pinch Calculations

Recent two-dimensional radiation magnetohydrodynamic (2-D RMHD) calculations of radiating Z-pinches agree well with integral data (current waveform, yield and power). The agreement between these calculations and detailed data, such as time-resolved X-ray images, is generally not as good. Improved physics models of Z-pinches, which better match detailed data, are needed to have true predictive capability. Furthermore, a better understanding of small-scale features may be crucial in designing and evaluating application experiments that use central targets. To address these problems, we first determine which integral data are most sensitive to the details in the models. This information is then used to investigate aspects of the pinch to which the data is sensitive, using non-standard techniques. For example, the pinch is calculated in (x,y) coordinates to investigate how a non-symmetric implosion affects the simulated data and whether the simulated data can be made to match the X-ray images as well as the integral data.