论文标题
发电机模拟产生土星样的小磁偶极子倾斜
A dynamo simulation generating Saturn-like small magnetic dipole tilts
论文作者
论文摘要
在行星发电机中，土星的磁场在其轴对称的特殊水平上脱颖而出。它的特殊特征之一是，相对于行星旋转轴倾斜的磁偶极模式仅$ \ \ \ of $ \大约0.007^{\ circ} $。在这种情况下执行的数值发电机模拟在产生如此小的偶极倾斜角方面遇到了很大的困难，而无需引入临时成分，例如外层中的纬度变化的热通量图案或稳定分层层（SSL）。在这里，我们提出了一个数值发电机模拟，该仿真可以平均生成高度轴对称的发电机，偶极式倾斜约为$ \ of $ \ of约0.0008^{\ circ} $。该模型由一个深的发电机层和上覆的低导电层组成，但没有任何SSL。我们强调了一种新型机制，其中大气层中产生的强差旋转渗透到发电机区域，有助于保持很小的磁偶极子倾斜。
Among planetary dynamos, the magnetic field of Saturn stands out in its exceptional level of axisymmetry. One of its peculiar features is that the magnetic dipole mode is tilted with respect to the planetary rotation axis by only $\approx 0.007^{\circ}$ or less. Numerical dynamo simulations performed in this context have had great difficulty in producing such small dipole tilt angles without introducing ad hoc ingredients such as a latitudinally varying heat flux pattern in the outer layers or stably stratified layers (SSL). Here we present a numerical dynamo simulation that generates a highly axisymmetric dynamo with a dipole tilt of about $\approx 0.0008^{\circ}$ on average. The model consists of a deep dynamo layer and an overlying low-conductivity layer but without any SSL. We highlight a novel mechanism where strong differential rotation generated in the atmospheric layer penetrates into the dynamo region, helping to maintain a very small magnetic dipole tilt.
