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

Abstract

Spherical Rayleigh–Taylor (RT) growth experiments of three-dimensional (3D) broadband nonuniformities were conducted in the acceleration phase of spherical implosions on OMEGA [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The targets consisted of 20- and 24-μm-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 ∼2×1014 W/cm2, high drive intensity of ∼1×1015 W/cm2, and a shaped pulse consisting of a low-intensity foot and high-intensity drive part (peak intensity of ∼1×1015 W/cm2). 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. T...