地磁极反转是地球上的“常规”现象。虽然间隔模式有时是不规则的(有时变化间隔之间有数百万年的差异)，但地球在过去的2000万年中已经进入了大约每20万- 30万年一次磁极反转的模式(来源:NASA)。基于这种模式和最近一次磁极切换发生的事实~78万年前， 地球“迟了”一次磁极切换。
我的问题:磁极切换发生的速度有多快?
是瞬时的吗?这需要几年时间吗?几千年?
当前的运动是长时间开关的极点部分，还是只是“正常”的极点运动?再一次，从NASA:
自19世纪初探险家第一次精确定位它以来，磁北极一直在向北爬行——超过600英里(1100公里)。事实上，它现在移动得更快了，科学家估计，北极每年向北移动约40英里，而20世纪初每年约10英里。< / p > < /引用>
From some previous research, it seems like it doesn't always make a "clean" switch either, with multiple poles appearing globally -- would this multi-pole extravaganza increase the switching time, or is it also normal?
Better resolution of the process and the time involved will require at least a 10-fold improvement in paleomagnetic sampling resolution, the authors contend. And one of the challenges is finding suitable lava flows or sediment layers that were created during the transition(s) in question.
As for whether current fluctuations indicate the earth is about to have a reversal: We can't tell, because the recent paleomagnetic record includes similar changes (sometimes regional rather than global) that did not result in reversals, Valet and Fournier write.
The present evolution falls within the normal range of field variability that prevailed for the past 2 Ma.
http://ceas.iisc.ernet.in/~bsreeni/gji14.pdf
支撑稳定偶极子的关键参数是螺旋度。强大的浮力抵消了外核的螺旋度，从而剥夺了稳定的偶极磁场。如果你想更多地了解我正在谈论的术语，这里有一个链接到一篇优秀的综述/介绍性论文