Growth rates of the ablative Rayleigh–Taylor instability in inertial confinement fusion
نویسندگان
چکیده
A simple procedure is developed to determine the Froude number Fr, the effective power index for thermal conduction n, the ablation-front thickness L0 , the ablation velocity Va , and the acceleration g of laser-accelerated ablation fronts. These parameters are determined by fitting the density and pressure profiles obtained from one-dimensional numerical simulations with the analytic isobaric profiles of Kull and Anisimov @Phys. Fluids 29, 2067 ~1986!#. These quantities are then used to calculate the growth rate of the ablative Rayleigh–Taylor instability using the theory developed by Goncharov et al. @Phys. Plasmas 3, 4665 ~1996!#. The complicated expression of the growth rate ~valid for arbitrary Froude numbers! derived by Goncharov et al. is simplified by using reasonably accurate fitting formulas. © 1998 American Institute of Physics. @S1070-664X~98!00705-8#
منابع مشابه
Growth Rates of the Ablative Rayleigh–Taylor Instability in Inertial Confinement Fusion
20 LLE Review, Volume 73 In recent years, several authors1–14 have studied the linear growth of the Rayleigh–Taylor (RT) instability in ablation fronts accelerated by laser irradiations. The determination of the instability growth rate is crucial to the success of inertial confinement fusion (ICF)15,16 because an excessive distortion of the front could lead to a severe degradation of the capsul...
متن کاملBubble acceleration in the ablative Rayleigh-Taylor instability.
The highly nonlinear evolution of the single-mode Rayleigh-Taylor instability (RTI) at the ablation front of an accelerated target is investigated in the parameter range typical of inertial confinement fusion implosions. A new phase of the nonlinear bubble evolution is discovered. After the linear growth phase and a short constant-velocity phase, it is found that the bubble is accelerated to ve...
متن کاملTheory of the Ablative Richtmyer–Meshkov Instability
30 LLE Review, Volume 77 In inertial confinement fusion (ICF) implosions, a laser irradiation induces a shock wave propagating through the target. During the shock transit time, the ablation front travels at a constant velocity, and any surface perturbations could grow due to the Richtmyer-Meshkov (RM)–like instability.1–5 Later, when a rarefaction wave reaches the ablation surface, the acceler...
متن کاملStabilizing effect of anisotropic thermal diffusion on the ablative Rayleigh-Taylor instability.
Linear theory of the ablative Rayleigh-Taylor instability in anisotropic diffusive materials is presented. This analysis indicates that enhancing diffusion in a plane transverse to the mean longitudinal flow can strongly reduce the growth of the instability. In the context of inertial confinement fusion, it is shown that anisotropic diffusion can be achieved using a laminated ablator made of su...
متن کاملSingle-mode Rayleigh–taylor Growth-rate Measurements
106 LLE Review, Volume 71 Understanding the growth of perturbations due to hydrodynamic instabilities is important to the design of direct-drive targets for the National Ignition Facility (NIF). Direct-drive inertial confinement fusion (ICF) has the potential to be more efficient than indirect-drive ICF; however, there is the potential for greater growth of hydrodynamic instabilities due to the...
متن کامل