Evolution of the gray opacity κ_gray for a sampling of fluid elements across all angles and depths, from simulations using different opacity models. Top row: Runs using the analytical expression from Wu et al. (2022, left) or the prescription from Just et al. (2022, right). Central row: Simulations with Rosseland (left) or Planck (right) gray opacities computed from the LANL data for neodymium as representative of the lanthanides. Bottom row: Rosseland mean opacity from the multigroup models using only neodymium to represent lanthanides (left) or also uranium as representative of actinides (right). The color bar is cut at κ_gray = 10⁻² cm²g⁻¹ for easier visualization. For each simulation, the top and bottom subpanels show the trajectories of the fluid elements in the density-temperature and density-cumulative lanthanides mass fraction (X_lan) planes, respectively. Markers indicate different orders of magnitudes of X_lan, with circles for X_lan < 5 × 10⁻⁵, downward triangles for 10⁻⁵ < X_lan < 10⁻³, upward triangles for 10⁻³ < X_lan < 5 × 10⁻², and stars for X_lan > 5 × 10⁻². For the simulations using only neodymium data, the background shows the single-element mean opacity κ_el calculated from the LANL tables (Rosseland for GK and Nd300, Planck for GKPl). Similarly, the uranium Rosseland mean opacity is shown in the NdU300 panel.