Signatures of flows in ion-temperature, areal-density and x-ray imaging data obtained in asymmetrically driven OMEGA DT implosions

Ion temperatures (T_ion) in Inertial Confinement Fusion (ICF) experiments are inferred from the broadening of primary neutron spectra. Directional motion (flow) of the fuel at burn, originating from asymmetries imposed by e.g. engineering features or drive non-uniformity, also impacts the broadening and may lead to artificially inflated “T_ion” values. Flow due to low-mode asymmetries is expected to give rise to line-of-sight variations in measured T_ion, as observed in OMEGA cryogenic DT implosions but not in similar experiments at the NIF. In this presentation, we report on OMEGA implosions intentionally driven asymmetrically to test the ability to predict and measure line-of-sight differences in apparent T_ion due to low-mode asymmetry-seeded flows. Neutron peak shift, areal-density asymmetry and x-ray imaging measurements are also brought to bear. These measurements are contrasted to CHIMERA, xRAGE and ASTER simulations, providing insights into implosion dynamics and the interplay between different asymmetry sources, including laser drive non-uniformity, stalk and capsule offset. The results highlight the complexity of hot-spot dynamics, which is a problem that must be mastered to achieve ICF ignition. This work was supported in part by the U.S. DOE, NLUF and LLE.