We report measurements of controlled implosion performance degradation
arising from the Rayleigh-Taylor instability in inertial confinement
fusion capsules. Using plastic capsules driven indirectly by the Nova
laser, we studied the variation in implosion performance as a function
of outer surface perturbation. Variations in both capsule x-ray and n
eutron emission are seen which are consistent with a model which descr
ibes mixing pusher material into fuel material. The model combines rep
resentative capsule surface characterization, implosion stability, and
perturbation growth saturation.