Numerical investigation on the stabilization of the deceleration phase Rayleigh-Taylor instability due to alpha particle heating in ignition target
Institute of Applied Physics and Computational Mathematics - P.O. Box 8009, Beijing 100088, PRC
Received: 30 May 2012
Accepted: 23 August 2012
Tritium-hydrogen-deuterium (THD) target is adopted in order to experimentally diagnose the properties of the ignition hot spot and the highly compressed main fusion fuel (Edwards M. J. et al., Phys. Plasmas, 18 (2011) 051003). As compared with deuterium-tritium (DT) target, the thermonuclear alpha particles which are needed to heat the fusion fuel, are much less in the THD target. In the present paper, the effect of alpha particle heating on the deceleration phase Rayleigh-Taylor instability (dp-RTI), which is one of the key problems in hot spot formation, is investigated systematically through numerical simulations. It is found that the mass ablation at the hot spot boundary is greatly increased due to the direct alpha particle heating. As a result, the dp-RTI growth rates are greatly reduced and the cut-off mode number decreases greatly from about 33 to 17. This explains why the hydrodynamic instability in the THD target grows more severely than in the DT ignition target.
PACS: 52.57.Fg – Implosion symmetry and hydrodynamic instability (Rayleigh-Taylor, Richtmyer-Meshkov, imprint, etc.) / 52.35.Py – Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.) / 47.20.Ma – Interfacial instabilities (e.g., Rayleigh-Taylor)
© EPLA, 2012