Z-pinch double-ended hohlraum energetics, coupling, and symmetry modeling compared with Z data

Symmetry tuning in the pulsed-power driven double-ended vacuum hohlraum allows highly symmetric capsule implosions, aided by the separation of the capsule from the z-pinch and its associated instabilities, spatial variations, and non-thermal spectral components. X-ray backlit capsule experiments at Z have demonstrated the ability to predictably nullify and control time-integrated P$_{2}$ asymmetry [1], and have measured the sensitivity of P$_{2}$ and P$_{4}$ asymmetry to hohlraum geometric parameters (hohlraum length, case-to-capsule ratio, etc.). Detailed two-dimensional Lasnex hohlraum simulations of these experiments will be presented. These simulations include: hohlraum radiation transport, time-dependent asymmetry due to z-pinch source motion, hohlraum absorption/re-emission, wall plasma motion, and the capsule ablation and implosion process. The measured trends in P$_{2}$ and P$_{4}$ can be generally understood using these simulations, although quantitative uncertainties remain as to the precise sources of these modes within the hohlraum. [1] G. R. Bennett \textit{et al}., Phys. Plas. \textbf{10}, 3717 (2003), R. A. Vesey \textit{et al}., Phys. Plas. \textbf{10}, 1854 (2003).