Reemission Ball and Symmetry-Capsule diagnostics for symmetry measurements

The most recent Livermore NIF design is a gas filled hohlraum without shine shields [1]. Two symmetry diagnostics, reemission ball and symmetry-capsule, are examined using the new ignition design. Both reemission ball and symmetry-capsules have been used in the past to measure capsule symmetry on NOVA experiments. [2-5] Livermore and Los Alamos scientists are now pursuing both concepts to study symmetry on NIF. [6] Here we compare the predicted symmetry for the two techniques. Issues related to the three-dimensional nature of the reemit diagnostic will be discussed. Issues such as the viewing holes in the hohlraum wall will be addressed by applying a three-dimensional view-factor code. \newline [1] Steve Haan et al., private communication \newline [2] Magelssen et al., Phy. Rev. E 57, 4663 (1998). \newline [3] Delamater et al., Phy. Rev. E 53, 5240 (1996). \newline [4] Hauer et al., Phys. Plasmas 2 (6), 2488 (1995). \newline [5] Harris et al., Bull. Am. Phys. Soc. 38, 1885 (1993). \newline [6] Don Meeker private, communication and Nels Hoffman, private communication