TY - JOUR
T1 - Preheating ablation effects on the Rayleigh-Taylor instability in the weakly nonlinear regime
AU - Wang, L. F.
AU - Ye, W. H.
AU - Sheng, Z. M.
AU - Don, Wai Sun
AU - Li, Y. J.
AU - He, X. T.
N1 - Funding Information:
The author (L.F.W.) would like to thank Professor S. Atzeni (Università di Roma “La Sapienza” and CNISM) and Professor K. Nishihara (Osaka University) for their helpful discussions and the anonymous referee for suggestions that have improved the paper. This research was supported by the National Basic Research Program of China (Grant No. 2007CB815100) and the National Natural Science Foundation of China (Grant Nos. 10935003, 11075024, 10905006, and 11074300). Both authors (W.S.D. and L.F.W.) would like to thank the support provided by the RGC grant from Hong Kong Research Grants Council. The author (L.F.W.) also would like to acknowledge the hospitality of the Department of Mathematics at Hong Kong Baptist University during his visit while conducting the research reported here.
PY - 2010/12
Y1 - 2010/12
N2 - The two-dimensional Rayleigh-Taylor instability (RTI) with and without thermal conduction is investigated by numerical simulation in the weakly nonlinear regime. A preheat model κ (T) = κSH [1+f (T)] is introduced for the thermal conduction [W. H. Ye, W. Y. Zhang, and X. T. He, Phys. Rev. E 65, 057401 (2002)], where κSH is the Spitzer-Härm electron thermal conductivity coefficient and f (T) models the preheating tongue effect in the cold plasma ahead of the ablation front. The preheating ablation effects on the RTI are studied by comparing the RTI with and without thermal conduction with identical density profile relevant to inertial confinement fusion experiments. It is found that the ablation effects strongly influence the mode coupling process, especially with short perturbation wavelength. Overall, the ablation effects stabilize the RTI. First, the linear growth rate is reduced, especially for short perturbation wavelengths and a cutoff wavelength is observed in simulations. Second, the second harmonic generation is reduced for short perturbation wavelengths. Third, the third-order negative feedback to the fundamental mode is strengthened, which plays a stabilization role. Finally, on the contrary, the ablation effects increase the generation of the third harmonic when the perturbation wavelengths are long. Our simulation results indicate that, in the weakly nonlinear regime, the ablation effects are weakened as the perturbation wavelength is increased. Numerical results obtained are in general agreement with the recent weakly nonlinear theories as proposed in [J. Sanz, J. Ramírez, R. Ramis, Phys. Rev. Lett. 89, 195002 (2002); J. Garnier, P.-A. Raviart, C. Cherfils-Cĺrouin, Phys. Rev. Lett. 90, 185003 (2003)].
AB - The two-dimensional Rayleigh-Taylor instability (RTI) with and without thermal conduction is investigated by numerical simulation in the weakly nonlinear regime. A preheat model κ (T) = κSH [1+f (T)] is introduced for the thermal conduction [W. H. Ye, W. Y. Zhang, and X. T. He, Phys. Rev. E 65, 057401 (2002)], where κSH is the Spitzer-Härm electron thermal conductivity coefficient and f (T) models the preheating tongue effect in the cold plasma ahead of the ablation front. The preheating ablation effects on the RTI are studied by comparing the RTI with and without thermal conduction with identical density profile relevant to inertial confinement fusion experiments. It is found that the ablation effects strongly influence the mode coupling process, especially with short perturbation wavelength. Overall, the ablation effects stabilize the RTI. First, the linear growth rate is reduced, especially for short perturbation wavelengths and a cutoff wavelength is observed in simulations. Second, the second harmonic generation is reduced for short perturbation wavelengths. Third, the third-order negative feedback to the fundamental mode is strengthened, which plays a stabilization role. Finally, on the contrary, the ablation effects increase the generation of the third harmonic when the perturbation wavelengths are long. Our simulation results indicate that, in the weakly nonlinear regime, the ablation effects are weakened as the perturbation wavelength is increased. Numerical results obtained are in general agreement with the recent weakly nonlinear theories as proposed in [J. Sanz, J. Ramírez, R. Ramis, Phys. Rev. Lett. 89, 195002 (2002); J. Garnier, P.-A. Raviart, C. Cherfils-Cĺrouin, Phys. Rev. Lett. 90, 185003 (2003)].
UR - http://www.scopus.com/inward/record.url?scp=78650859957&partnerID=8YFLogxK
U2 - 10.1063/1.3517606
DO - 10.1063/1.3517606
M3 - Journal article
AN - SCOPUS:78650859957
SN - 1070-664X
VL - 17
JO - Physics of Plasmas
JF - Physics of Plasmas
IS - 12
M1 - 122706
ER -