Rayleigh-Taylor (RT) instability is one of the most important physical issues in the inertial confinement fusion research. The reduction of its growth rate due to laser-driven ablation, which is described by the modified Takabe formula, is of great importance for-a precise understanding of the target physics. We have developed various diagnostic techniques for the measurement of the parameters appearing in the Takabe formula, such as the growth rate, the acceleration, the mass ablation rate, and the density structure including ablation density and density scalelength. Face-on and side-on x-ray backlighting were coupled with moire interferometry imaging, penumbral imaging, and Fresnel zoneplate imaging. All the physical parameters related to RT instability were measured experimentally, and compared with simulation results. (C) 2003 American Institute Of Physics.