Buffett BA
Department of Earth and Ocean Sciences, University of British Columbia, 2219 Main Mall, Vancouver, BC, Canada V6T 1Z4. E-mail:
Science. 2000 Jun 16;288(5473):2007-12. doi: 10.1126/science.288.5473.2007.
Earth's magnetic field is generated by fluid motion in the liquid iron core. Details of how this occurs are now emerging from numerical simulations that achieve a self-sustaining magnetic field. Early results predict a dominant dipole field outside the core, and some models even reproduce magnetic reversals. The simulations also show how different patterns of flow can produce similar external fields. Efforts to distinguish between the various possibilities appeal to observations of the time-dependent behavior of the field. Important constraints will come from geological records of the magnetic field in the past.
地球磁场是由液态铁核中的流体运动产生的。关于这一过程如何发生的细节，现在正从实现自持磁场的数值模拟中显现出来。早期结果预测，地核外部存在一个占主导地位的偶极场，一些模型甚至能再现磁场反转。模拟还展示了不同的流动模式如何产生相似的外部磁场。区分各种可能性的努力诉诸于对磁场随时间变化行为的观测。重要的限制将来自过去磁场的地质记录。
