MEASUREMENTS OF RAYLEIGH-TAYLOR GROWTH-RATE OF PLANAR TARGETS IRRADIATED DIRECTLY BY PARTIALLY COHERENT-LIGHT

We report the first measurements of laser-driven Rayleigh-Taylor insta bility at the linear growth regime in an imprint-free condition. Initi ally rippled polystyrene foils were irradiated by the partially cohere nt light. We measured temporal evolution of areal-density perturbation by the face-on x-ray backlighting technique. The observed maximum gro wth factor was nearly 50. We also measured the acceleration of the irr adiated foil. The growth rate was approximately 50% of the classical g rowth rate. These experimental results were well reproduced by a two-d imensional simulation coupled with the Fokker-Planck treatment of elec tron heat transport.