Excitation of stellar p-modes by turbulent convection - II. The Sun
Excitation of stellar p-modes by turbulent convection - II. The Sun
复制标题
湍流对流激发恒星 p 模式 - II。
DOI：
10.1051/0004-6361:20010213
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发表时间：
2001
影响因子：
6.5
通讯作者：
Dasgal Observatoire de Paris
中科院分区：
文献类型：
--
作者：
R. Samadi;M. Goupil;Yveline Lebreton Despa Observatoire de Paris;Dasgal Observatoire de Paris
计算的太阳模型的径向振荡的声功率和振荡幅度与太阳地震观测进行了比较。假设振荡是由湍流随机激发的。数值计算基于Samadi等人（2000）在配套论文中提出的进入类太阳振荡模式的功率的理论公式。这个公式允许调查几个假设有关的恒星湍流的属性。与Goldreich等人（1994）的研究结果一致，我们发现熵源在随机激励中起主导作用，而非熵应力源。我们考虑几个湍流动能谱建议不同的观测太阳颗粒。湍流谱之间的差异表现为在高振荡频率下计算的振荡功率的巨大差异。在湍流描述中引入的两个自由参数进入声功率的表达式。这些参数进行调整，以适应太阳观测的表面速度振荡。最好的拟合是用Nesis等人（1993）从太阳颗粒化观测中推导出的动能谱得到的;相应的调整参数被发现与可以设置在这些参数上的理论上限相一致。所采用的理论方法提高了太阳地震观测和数值计算结果之间的一致性。
Acoustic power and oscillation amplitudes of radial oscillations computed for a solar model are compared with solar seismic observations. The oscillations are assumed stochastically excited by turbulence. The numerical computations are based upon a theoretical formulation of the power going into solar like oscillation modes as proposed by Samadi et al. (2000) in a companion paper. This formulation allows to investigate several assumptions concerning properties of the stellar turbulence. We find that the entropy source plays a dominant role in the stochastic excitation compared with the Reynold stress source in agreement with Goldreich et al. (1994). We consider several turbulent kinetic energy spectra suggested by different observations of the solar granulation. Differences between turbulent spectra manifest themselves by large differences in the computed oscillation powers at high oscillation frequency. Two free parameters which are introduced in the description of the turbulence enter the expression for the acoustic power. These parameters are adjusted in order to fit to the solar observations of the surface velocity oscillations. The best fit is obtained with the kinetic energy spectrum deduced from the observations of the solar granulation by Nesis et al. (1993); the corresponding adjusted parameters are found to be compatible with the theoretical upper limit which can be set on these parameters. The adopted theoretical approach improves the agreement between solar seismic observations and numerical results.