Numerical simulation of mixing in supernova ejecta

超新星喷射物混合的数值模拟

基本信息

批准号：
02640204
负责人：
HACHISU Izumi
金额：
$ 1.02万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02640204/
关键词：
Hydrodynamics SN 1987A Supernovae Instabilities Mixing レイリ-テイラ-不安定光度曲線 X線ガンマ線

项目摘要

Observations of SN 1987A strongly suggest the occurrence of large scale mixing during the explosion. The most promising mechanism to mix the ejecta is the Rayleigh-Taylor(R-T)instability so that we have numerically follow a nonlinear growth of the R-T instability using a much more refined two-dimensional(2-D)axisymmetric hydrodynamic code than in our previous work. The growth of the R-T instability depends strongly on the amplitude of the initial perturbation. It is found that the instabilities grow considerably even if we perturb the velocity field by 1%. The HE/C+O interface is not so unstable while the instability is pronounced at the H/He interface. Eventually the core material(inside the carbon-oxygen layer)is mixed up to the layer having an expansion velocity of - 2000 km s^<-1> for a 5% random perturbation. At the same time, hydrogen is mixed down to the core having an expansion velocity of - 500 km s^<-1> for the 5% random perturbation. Heavy elements are preferentially concentrated into the high-density fingers and mushroom heads with a density contrast of - 5-6. These results are essentially the same as in our previous results obtained by a more diffusive hydrodynamic code. However, we have failed to mix ^<56>Ni into the envelope having an expansion velocity of 3000-4000 km s^<-1>. The R-T instability alone may not convey ^<56>Ni into the very surface layer.

SN 1987a的观察结果强烈表明爆炸过程中发生了大规模混合。混合喷射的最有希望的机制是雷利 - 泰勒（R-T）的不稳定性，因此我们使用更精致的二维（2-D）轴对称水动力学代码的数值遵循R-T不稳定性的非线性生长。 R-T不稳定性的生长在很大程度上取决于初始扰动的幅度。发现即使我们将速度场扰动1％，不稳定性也会大大增长。 HE/C+O接口在H/HE接口处发音时不那么不稳定。最终，对于5％的随机扰动，将核心材料（在碳氧层内部内部）混合到其膨胀速度为-2000 km S^<-1>的层。同时，对于5％随机扰动，将氢混合到其膨胀速度为-500 km S^<-1>的核心。重元素优先集中在高密度的手指和蘑菇头上，密度为-5-6。这些结果基本上与我们先前通过更扩散的流体动力代码获得的结果相同。但是，我们未能将 ^<56> Ni混合到包络中，其膨胀速度为3000-4000 km s ^<-1>。仅R-T不稳定性可能不会将 ^<56> Ni传递到非常表面的层中。