Core Dynamics and the Geodynamo

地球的磁场是由流过地球熔融铁芯的电流产生的。这些电流是由自激发电机作用产生的。就像在发电站里一样，导体在磁场存在下的运动产生电流，而电流又产生磁场本身。地核流体运动的能量来源通常被认为是地球冷却时固体内核表面释放的物质的热和成分浮力，并且成功的地球动力学模拟是基于这一想法。还有另一种可能的能量来源，即地球自转轴的日-日进动。这从未被评估为地球磁力的可能来源。这项研究的目的是确定岁差是否能维持一个产生类似地球磁场的地球发电机。如果失败，其目标将是找出旋进力如何改变成功的浮力驱动地球发电机产生的磁场。

Roberts EAR-0074015 The magnetic field of the Earth is created by electric currents flowing in the Earth's molten-iron core. These currents are generated by self-excited dynamo action. As in a power station, the motion of the conductor in the presence of the magnetic field produces the currents that create the magnetic field itself. The energy source for the fluid motions in the Earth's core is commonly supposed to be the thermal and compositional buoyancy of material released at the surface of the solid inner core as the Earth cools, and successful geodynamo simulations have been based on this idea. There is also a second possible energy source, the luni-solar precession of the Earth's axis of rotation. This has never been evaluated as a possible source of the Earth's magnetism. It is the object of this investigation to determine whether precession can maintain a geodynamo that creates an Earth-like field. If it fails to do so, the aim will be to find how precessional forces alter the fields produced by the successful buoyancy-driven geodynamo.