On a dynamo driven by topographic precession
On a dynamo driven by topographic precession
复制标题
DOI：
10.1080/03091920903311788
复制
发表时间：
2009-11
影响因子：
1.3
通讯作者：
Cheng-Chin Wu;P. Roberts
中科院分区：
文献类型：
--
作者：
Cheng-Chin Wu;P. Roberts
半个多世纪以前，布拉德提出地球的发电机可能是由地核中日月进动产生的运动驱动的。地幔的岁差强迫运动通过粘性力驱动地核流动，同时由于地幔深处的导电性，也通过磁力驱动地核流动。这两种耦合与地核-地幔界面的扁性所造成的地形耦合相比，被认为是微不足道的。由于研究非球形导电流体中发电机作用的技术困难，这是研究地形强迫流动中发电机作用的第一次认真尝试。它描述了所采用的新的数值方法，为验证这些方法而设计的测试，以及这些测试的成功结果。给出了这些发电机的一些初步结果。结果表明，在一定的参数范围内，发电机产生的磁场增强了旋进运动的活力。
More than half a century ago, Bullard suggested that the Earth's dynamo might be driven by the motions created in the Earth's core by the luni-solar precession. The precessionally forced motion of the mantle drives core flow through viscous forces and also, because of the electrical conductivity of the deep mantle, through magnetic forces. Both these couplings are thought to be insignificant in comparison with the topographical coupling created by the oblateness of the core-mantle interface. Because of technical difficulties in studying dynamo action in non-spherical bodies of electrically conducting fluid, this is the first serious attempt to study dynamo action by topographically forced flows. It describes the novel numerical methods that were employed, the tests that were devised to validate these methods, and the successful outcome of those tests. Some preliminary results for these dynamos are presented. It is shown that, in some parameter ranges, the magnetic field produced by the dynamos enhances the vigor of the precessional motions.