Time-Resolved Polar X-Ray Images of Capsule Implosions on the NIF*

Key experiments leading to ignition at the National Ignition Facility (NIF) involve measuring the symmetry of imploding capsules using images recorded by x-ray framing cameras. Recent polar x-ray images display a wide variety of interesting features including four-fold azimuthal symmetry. We describe techniques that have been developed to quantify the azimuthal shape and explain the physical phenomena associated with features observed in the images.