The Spherical Accretion Shock Instability in the Linear Regime
The Spherical Accretion Shock Instability in the Linear Regime
复制标题
线性状态下的球形吸积激波不稳定性
DOI：
10.1086/500817
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
A. Mezzacappa
中科院分区：
文献类型：
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作者：
J. Blondin;A. Mezzacappa
我们使用时间相关的，轴对称的，流体动力学模拟研究的线性稳定性的停滞，球形吸积激波，出现在核心坍缩超新星的后反弹阶段。我们表明，这种吸积冲击是稳定的径向模式，与Houck和Chevalier的线性稳定性分析密切一致的衰减率和振荡频率。对于非球形扰动，我们发现，l = 1模式总是不稳定的参数适当的核心坍缩超新星。我们还发现，l = 2模式是不稳定的，但通常具有小于l = 1的增长率。此外，l = 1模式是唯一的模式过渡到一个非线性阶段，在我们的模拟。这一结果提供了一个可能的解释，在许多核心坍缩超新星的二维模拟中看到的l = 1“晃动”模式的主导地位。
We use time-dependent, axisymmetric, hydrodynamic simulations to study the linear stability of the stalled, spherical accretion shock that arises in the postbounce phase of core-collapse supernovae. We show that this accretion shock is stable to radial modes, with decay rates and oscillation frequencies in close agreement with the linear stability analysis of Houck and Chevalier. For nonspherical perturbations we find that the l = 1 mode is always unstable for parameters appropriate to core-collapse supernovae. We also find that the l = 2 mode is unstable, but typically has a growth rate smaller than that for l = 1. Furthermore, the l = 1 mode is the only mode found to transition into a nonlinear stage in our simulations. This result provides a possible explanation for the dominance of an l = 1 "sloshing" mode seen in many two-dimensional simulations of core-collapse supernovae.