| 太阳5分钟振荡的激发机制 |
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| 引用本文： | 熊大闰,邓李才.太阳5分钟振荡的激发机制[J].天文学报,2009,50(4). |
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| 作者姓名： | 熊大闰 邓李才 |
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| 作者单位： | 1. 中国科学院紫金山天文台,南京,210008
2. 中国科学院国家天文台,北京,100012 |
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| 基金项目： | 国家自然科学基金(10773029、10573022)项目和中国科技部2007CB815406项目共同资助 |
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| 摘 要： | 1 引言 太阳5分钟振荡是上世纪1个重要的发现1],它使得人们可以通过观测太阳表面的振动来探测其内部的结构,日震学已取得了巨大的进展,然而我们至今仍不了解其脉动的激发机制,它依然是1个存在争议的问题.太阳位于造父变星脉动不稳定区之外,所以大多数人都相信,由于对流的阻尼,太阳是脉动稳定的,太阳和太阳型恒星的振荡都是由所谓的湍流随机激发机制所激发2-8].
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| 关 键 词： | 对流 太阳 振荡 |
On the Excitation Mechanism of Solar Five-minute Oscillations |
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| XIONG Da-run,DENG Li-cai.On the Excitation Mechanism of Solar Five-minute Oscillations[J].Acta Astronomica Sinica,2009,50(4). |
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| Authors: | XIONG Da-run DENG Li-cai |
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| Abstract: | The excitation mechanism of solar five-minute oscillations is studied in this paper. We calculated the non-adiabatic oscillations of low- and intermediate-degree (l= 1-25) g4-p39 modes for the Sun. Both the thermodynamic and dynamic couplings are taken into account by using our non-local and time-dependent theory of convection. The results show that all the low-frequency f- and p-modes with periods P > 5.4 minutes are pulsationally unstable, while the coupling between convection and oscillations is neglected. However, when the convection coupling is taken into account, all the g- and low-frequency f- and p-modes with periods longer than ～16 minutes (except the low-degree pl-modes) and the high frequency p-modes with periods shorter than ～3 minutes become stable, and the intermediate-frequency p-modes with period from～3 to ～16 minutes are pulsationally unstable. The pulsation amplitude growth rates depend only on the frequency and almost do not depend on l They achieve the maximum at v ~ 3700 μHz (or P ~ 270 seconds). The coupling between convection and oscillations plays a key role for stabilization of low-frequency f- and p-modes and excitation of intermediate-frequency p-modes. We propose that the solar 5-minute oscillations are not caused by any single excitation mechanism, but they are resulted from the combined effect of "regular" coupling between convection and oscillations and turbulent stochastic excitation. For low- and intermediate-frequency p-modes, the coupling between convection and oscillations dominates; while for high-frequency modes, stochastic excitation dominates. |
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| Keywords: | Convection Sun:Oscillations |
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