Dynamics of the solar tachocline - III. Numerical solutions of the Gough and McIntyre model
Dynamics of the solar tachocline - III. Numerical solutions of the Gough and McIntyre model
复制标题
DOI：
10.1093/mnras/stt1065
复制
发表时间：
2013-09-01
影响因子：
4.8
通讯作者：
Wood, T. S.
中科院分区：
文献类型：
--
作者：
Acevedo-Arreguin, L. A.;Garaud, P.;Wood, T. S.
我们提出了第一个太阳内部的数值模拟，显示了与Gough和McIntyre模型一致的速斜。我们找到了非线性、轴对称、稳态的数值解，其中：(1)大尺度的原始场被下行的经向流限制在辐射区内，这些流在对流区被陀螺仪泵送；(2)辐射区基本均匀旋转，旋转速率与观测值一致；(3)高纬速斜的大部分处于热风平衡状态，洛伦兹力对其动力学的影响可以忽略不计；(4)磁场与流动之间的相互作用发生在一个非常薄的磁边界层内，即速层顶，位于速斜的底部。我们表明，高纬速斜的厚度与经向流的振幅完全符合Gough和McIntyre的预测。我们还确定了可以获得此类解的参数范围，并为先前在重现Gough和McIntyre模型的数值尝试的失败提供了简单的解释。最后，我们讨论了我们的发现对未来太阳内部数值模型的影响，以及对未来太阳和其他恒星观测的影响。
We present the first numerical simulations of the solar interior to exhibit a tachocline consistent with the Gough and McIntyre model. We find non-linear, axisymmetric, steady-state numerical solutions in which: (1) a large-scale primordial field is confined within the radiation zone by downwelling meridional flows that are gyroscopically pumped in the convection zone; (2) the radiation zone is in almost uniform rotation, with a rotation rate consistent with observations; (3) the bulk of the high-latitude tachocline is in thermal-wind balance, and the Lorentz force plays a negligible role in its dynamics; (4) the interaction between the field and the flows takes place within a very thin magnetic boundary layer, the tachopause, located at the bottom of the tachocline. We show that the thickness of the high-latitude tachocline scales with the amplitude of the meridional flows exactly as predicted by Gough and McIntyre. We also determine the parameter range in which such solutions can be obtained, and provide a simple explanation for the failure of previous numerical attempts at reproducing the Gough and McIntyre model. Finally, we discuss the implications of our findings for future numerical models of the solar interior, and for future observations of the Sun and other stars.