Spherical Rayleigh-Taylor growth of three-dimensional broadband perturbations on OMEGA

Spherical Rayleigh-Taylor (RT) growth experiments of three-dimensional (3131) broadband nonuniformities were conducted in the acceleration phase of spherical implosions oil OMEGA [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The targets consisted of 20- and 24-mu m-thick plastic spherical shells having diagnostic openings for backlighter x rays to image shell modulations. Experiments were conducted with square laser pulses at a low drive intensity of similar to 2 x 10(14) W/cm(2), high drive intensity of similar to 1 x 10(15) W/cm(2) and a shaped pulse consisting of a low-intensity foot and high-intensity drive part (peak intensity of similar to 1 x 10(15) W/cm(2)). In low-intensity experiments, large RT growth was measured, resulting in shells being broken up by 3D modulations at the end of the drive. In the high-intensity experiments, no RT growth of the 3D modulations was detected. In the shaped-pulse experiments, perturbations grew during the low-intensity part of the drive and were stabilized later during the high-intensity part of the drive. The measured RT growth stabilization with the high-intensity drive was similar to previous observations in planar geometry [V. A. Smalyuk et al., Phys. Rev. Lett. 101, 025002 (2008)]. (C) 2009 American Institute of Physics. [doi:10.1063/1.3253321]