Hot-spot mix in large-scale HDC implosions at NIF
A. B. Zylstra, D. T. Casey, A. L. Kritcher, L. Pickworth, B. Bachmann, K. L. Baker, Juergen Biener, T. Braun, D. S. Clark, V. Geppert-Kleinrath, M. Hohenberger, C. Kong, S. Le Pape, A. Nikroo, N. Rice, M. S. Rubery, Michael Stadermann, D. J. Strozzi, C. A. Thomas, P. L. Volegov, C. R. Weber, C. Wild, C. H. Wilde, D. A. Callahan, O. A. Hurricane
Abstract
Mix of high-Z material from the capsule into the fuel can severely degrade the performance of inertial fusion implosions. On the Hybrid B campaign, testing the largest high-density-carbon capsules yet fielded at the National Ignition Facility, several shots show signatures of high levels of hot-spot mix. We attribute a ∼40% yield degradation on these shots to the hot-spot mix, comparable to the level of degradation from large P2 asymmetries observed on some shots. A range of instability growth factors and diamond crystallinity were tested and they do not determine the level of mix for these implosions, which is instead set by the capsule quality.