Seeing the Northern Lights at the equator? Predicting the next reversal of Earth's magnetic field

地磁场是地球的基本组成部分，至少存在了35亿年。然而，磁场远不是一个常量，而是非常动态的，表现出缓慢的波动和漂移的磁极，偶尔会在极性上完全反转。在全球磁场反转期间，地球通常很强的偶极场分裂成多个磁极，每个磁极漂移到地球表面。很可能在每一个极光周围都形成了一个局部极光椭圆形，使得北极光可以出现在任何靠近极点的地方--甚至在赤道。磁场以看不见的力场的形式围绕着我们的星球，为地球表面的生命和现代技术基础设施提供长期保护，使其免受有害的太阳辐射的伤害。虽然目前的逆转速度大约是每百万年2-3次，但上一次全球逆转发生在大约78万年前，这意味着地球现在早就应该发生逆转了。不管是真是假，变化正在发生：南大西洋的一小块弱场(南大西洋异常)正在扩散；全球磁场(用偶极子强度表示)正在以每世纪5%的速度减弱；过去几十年的最新测量表明，磁北极已经开始从加拿大北部的历史位置向西伯利亚冲刺。这是否意味着全球磁场即将迎来一段显著变化的时期？预测磁场是具有挑战性的，尤其是因为我们还没有一个完整的表示来描述磁场如何变化。虽然基本的物理原理已经被理解，但地核内部的复杂性和极端条件使得它在计算上很难建模。该项目的新方面是将机器学习或深度学习的最新进展应用于地球磁场的预测。该项目背后的关键思想是，经过训练的神经网络可能能够发现数据中的模式，这些模式到目前为止要么没有被注意到，要么太复杂而无法解释；这样的网络或许能够提供对内部产生的磁场的准确的短期预测。该项目的目标之一是评估地磁场是否可能逆转以及逆转的速度有多快。

The geomagnetic field is a fundamental part of planet Earth, existing for at least 3.5 billion years. Yet far from being a constant, the field is very dynamic, exhibiting slow fluctuations and wandering magnetic poles which occasionally fully reverse in polarity. During a global magnetic field reversal, the usually strong dipolar field of the Earth fragments into multiple magnetic poles each of which drift across the planet's surface. It is likely that around every one a local auroral oval forms allowing the 'northern lights' to appear anywhere a pole was close by - even at the equator.The magnetic field wraps around our planet as an invisible force-field, providing long-term protection to life on the surface and modern technological infrastructure from harmful solar radiation. Although the current rate of reversals is about 2-3 times per million years, the last global reversal took place some 780,000 years ago, meaning that planet Earth is now well "overdue" a reversal. True or not, it is certainly the case that change is afoot: a patch of weak field in the south Atlantic (the south Atlantic anomaly) is spreading; the global field (expressed by the dipole strength) is weakening at a rate of 5% per century; and very recent measurements over the last few decades have shown that the magnetic North Pole has begun a sprint away from its historical position over northern Canada towards Siberia. Does this indicate that a period of significant change for the global field is upon us?Predicting the magnetic field is challenging, not the least because we do not yet have a complete representation that describes how the magnetic field changes. Although the basic physics is understood, the complexities and extreme conditions within the Earth's core make it computationally difficult to model. The novel aspect of this project is to apply recent advances in Machine Learning or Deep Learning to the prediction of Earth's magnetic field. The key idea behind the project is that a trained neural network may be able to spot patterns in the data that have so far either not been noticed or have been too complex to interpret; such networks may be able to supply accurate short-time forecasts of the internally generated magnetic field. One of the goals of the project is to assess the evidence for whether the geomagnetic field is likely to reverse and how fast it might do so.