Ablation front Rayleigh-Taylor growth experiments in spherically convergent geometry

Experiments were performed on the Nova laser [E. M. Campbell et al., Rev. S ci. Instrum. 57, 2101 (1986)], using indirectly driven capsules mounted in cylindrical gold hohlraums, to measure the Rayleigh-Taylor growth at the ab lation front by time-resolved radiography. Modulations were preformed on th e surface of Ge-doped plastic capsules. With initial modulation amplitude o f 2-2.5 mu m, growth factors of about six in optical depth were seen, in ag reement with simulations using the radiation hydrocode FCI2 [G. Schurtz, La fusion thermonucleaire inertielle par laser, edited by R. Dautray et al. ( Eyrolles, Paris, 1994), Vol. 2]. With initial modulation amplitude of 0.5 m u m and a longer drive, growth factors of about 100-150 in optical depth we re seen. Comparable planar experiments showed growth factors of about 40 in optical depth. Analytical models predict the observed growth factors. (C) 2000 American Institute of Physics. [S1070-664X(00)94605-6].