ON LIMITING THE THICKNESS OF THE SOLAR TACHOCLINE
ON LIMITING THE THICKNESS OF THE SOLAR TACHOCLINE
复制标题
论限制太阳速斜线的厚度
DOI：
10.1088/0004-637x/733/1/12
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
T. Rogers
中科院分区：
文献类型：
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作者：
T. Rogers
为了研究太阳辐射内部的角动量演化，我们提出了太阳内部对流和辐射耦合区域的轴对称模拟。运行了流体力学和磁流体力学模型。我们发现了一个初始的快速调整，其中对流区的微分旋转粘性地扩散到辐射内部，从而形成了一个“速斜”。在极地地区，塔切斜随后的扩散被在塔切斜中形成的一个反向旋转的经向环流细胞所阻止。在赤道附近，这种反向旋转的环流更加断断续续，速斜穿透深度继续增加，尽管比先前预测的要慢。在磁性模型中，我们施加了一个最初局限于辐射内部的偶极场。磁性模型的行为与非磁性模型非常相似。尽管与对流区相连，但很少有角动量在对流区和辐射区之间传递。因此，虽然磁场似乎不是阻止速斜传播的必要条件，但如果与对流区相连，磁场也不会促进这种传播。
We present axisymmetric simulations of the coupled convective and radiative regions in the Sun in order to investigate the angular momentum evolution of the radiative interior. Both hydrodynamic and magnetohydrodynamic models were run. We find an initial rapid adjustment in which the differential rotation of the convection zone viscously spreads into the radiative interior, thus forming a “tachocline.” In polar regions, the subsequent spread of the tachocline is halted by a counterrotating meridional circulation cell which develops in the tachocline. Near the equator such a counterrotating cell is more intermittent and the tachocline penetration depth continues to increase, albeit more slowly than previously predicted. In the magnetic models, we impose a dipolar field initially confined to the radiative interior. The behavior of the magnetic models is very similar to their non-magnetic counterparts. Despite being connected to the convection zone, very little angular momentum is transferred between the convective and radiative regions. Therefore, while it appears that a magnetic field is not necessary to stop the tachocline spread, it also does not promote such a spread if connected to the convection zone.