Nonlinear Theory of the Ablative Rayleigh-Taylor Instability

Journal Article · Fri Dec 03 04:00:00 EST 2004 · Plasma Physics and Controlled Fusion

DOI:https://doi.org/10.1088/0741-3335/46/12B/032· OSTI ID:834812

Sanz, J ^[1]; Betti, R; Ramis, R; Ramirez, J

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1. Laboratory for Laser Energetics, University of Rochester, Rochester, NY

Here, a model for the nonlinear Rayleigh-Talyor instability (RTI) of a steady ablation front based on a sharp boundary approximation is presented. The model includes the effect of mass ablation and represents a basic tool for investigating many aspects of the nonlinear ablative RTI relevant to inertial confinement fusion. The single mode analysis shows the development of a nonlinear exponential instability for wave numbers close to the linear cutoff. Such a nonlinear instability grows at a rate faster than the linear growth rate and leads to saturation amplitudes significantly larger than the classical value 0.1 lambda. We also found that linearly stable perturbations with wave numbers larger than the linear cutoff become unstable when their initial amplitudes exceed a threshold vlaue. The shedding of long wavelength modes via mode coupling is much greater than predicted by the classical RTI theory. The effects of ablation on the evolution of a front of bubbles is also investigated and the front acceleration is computed.

• Research Organization: Laboratory for Laser Energetics
• Sponsoring Organization: USDOE
• DOE Contract Number: FC52-92SF19460
• OSTI ID: 834812
• Report Number(s): DOE/SF-19460-571; 1496; 2004-141
• Journal Information: Plasma Physics and Controlled Fusion, Journal Name: Plasma Physics and Controlled Fusion Vol. 46
• Country of Publication: United States
• Language: English