The existence of the Λ effect in the solar convection zone as indicated by SDO/HMI data
The existence of the Λ effect in the solar convection zone as indicated by SDO/HMI data
复制标题
SDO/HMI 数据表明太阳对流区存在 Î 效应
DOI：
10.1051/0004-6361/201424953
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发表时间：
2014
影响因子：
6.5
通讯作者：
Tereshin
中科院分区：
文献类型：
--
作者：
Rüdiger;Kueker;Tereshin
利用太阳动力学天文台（SDO）的数据，对太阳巨电池在北方（南）半球的正（负）水平雷诺应力的经验发现（海瑟薇等人，2013年）进行了讨论，讨论了其对太阳/恒星差异旋转理论的影响。在忽略纬向环流的情况下求解角速度的非线性Reynolds方程，结果表明，在Lambda效应的作用下，北方半球的水平Reynolds应力在太阳对流区的表面总是负的，而在大部分区域是正的。描述刚性旋转各向异性湍流的角动量输运的Lambda效应，避免了对流区的刚体旋转，它在旋转速率的三次方的水平方向上，并且总是指向赤道。没有Lambda效应的理论也可能仅通过纬向环流的作用提供观测到的太阳自转规律，这导致了与观测到的符号相反的水平雷诺应力。
The empirical finding with data from the Solar Dynamics Observatory (SDO) of positive (negative) horizontal Reynolds stress at the northern (southern) hemisphere for solar giant cells (Hathaway et al. 2013) is discussed for its consequences for the theory of the solar/stellar differential rotation. Solving the nonlinear Reynolds equation for the angular velocity under neglect of the meridional circulation we show that the horizontal Reynolds stress of the northern hemisphere is always negative at the surface but it is positive in the bulk of the solar convection zone by the action of the Lambda effect. The Lambda effect, which describes the angular momentum transport of rigidly rotating anisotropic turbulence and which avoids a rigid-body rotation of the convection zones, is in horizontal direction of cubic power in the rotation rateand it is always equatorwards directed. Theories without Lambda effect which may also provide the observed solar rotation law only by the action of a meridional circulation lead to a horizontal Reynolds stress with the opposite sign as observed.