Nonlinear growth of dynamical overstabilities in blast waves. [effects on supernova remnants]
Nonlinear growth of dynamical overstabilities in blast waves. [effects on supernova remnants]
复制标题
爆炸波中动态超稳定性的非线性增长。
DOI：
10.1086/172506
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
M. Norman
中科院分区：
文献类型：
--
作者：
M. M. Low;M. Norman
维什尼亚克已经证明，冲击波会受到振荡不稳定性的影响，当冲击波足够薄时，就会发生增长。这种超稳定性的非线性发展尚未确定。我们使用数值气体动力学程序ZEUS-2D直接模拟超稳定性。我们确认的线性分析，通过扰动爆炸波与低振幅的本征函数的过稳定性。然后，我们增加扰动的幅度，以确定的非线性行为的超稳定性。我们发现，由于壳内的弱横向冲击，超稳定性饱和。致密壳层中的横向速度达到激波后声速，并形成壳层厚度量级的高密度区
Blast waves have been shown by Vishniac to be subject to an oscillating instability, with growth occurring when the blast wave is thin enough. The nonlinear development of this overstability has not yet been determined. We directly model the overstability using the numerical gas dynamics code ZEUS-2D. We confirm the linear analysis by perturbing a blast wave with a low-amplitude eigenfunction of the overstability. We then increase the amplitude of the perturbations to determine the nonlinear behavior of the overstability. We find that the overstability saturates due to weak transverse shocks in the shell. Transverse velocities in the dense shell reach the postshock sound speed, and high-density regions with sizes of order the shell thickness form