DIRECT-DRIVE HYDRODYNAMIC INSTABILITY EXPERIMENTS ON THE GEKKO XII LASER

Hydrodynamic instabilities, such as the Rayleigh-Taylor (R-T) instabil ity, play a critical role in inertial confinement fusion as they final ly cause fuel-pusher mixing that potentially quenches thermonuclear ig nition. Good understanding of the instabilities is necessary to limit the mixing within a tolerable level. A series of experiments has been conducted on the GEKKO XII laser facility [C. Yamanaka et al., IEEE J. Quantum Electron. QE-17, 1639 (1981)] to measure hydrodynamic instabi lities in planar foils directly irradiated by 0.53 mu m laser light. I t has been found that (1) the imprint is reasonably explained by an im print model based on the equation of motion with the pressure perturba tion smoothed by the cloudy-day effect, and (2) the experimental R-T g rowth rate is significantly reduced from the classical growth rate due probably to ablative stabilization enhanced by nonlocal heat transpor t. (C) 1997 American Institute of Physics. [S1070-664X(97)0-2811-5].