CSEDI Collaborative Research: Towards a unified model of the geomagnetic, geochemical, and thermal evolutions of Earth's mantle and core

地球的磁场是在地球铁芯的流体部分产生的，它保护地球和轨道卫星免受来自太空的潜在有害带电粒子的冲击。古代岩石的磁化向我们表明，磁场已经屏蔽地球至少35亿年了。超过这个年龄，目前还没有观测到磁场是否存在。磁场究竟是什么时候产生的，这是一个谜，也是一个具有挑战性的谜题，即它是如何持续数十亿年的。这些问题的答案将极大地影响我们对地球如何从最初的状态演变成一个能够在其表面发展和维持生命的宜居行星的理解。这项提议的研究旨在通过观察覆盖在地核上的深层岩浆海洋在帮助维持古代磁场方面可能发挥的作用，采取一种新的方法来回答这些难题。最近的实验能够模拟地球内部深处的极端压力和温度，为了解地球物质在这种条件下的行为提供了新的知识。利用最近获得的关于材料特性的信息，结合磁场产生能量学的理论考虑，该项目将建立基于物理的地球内部和随时间冷却的模型。这些努力将专门研究在地核顶部存在长期存在的岩浆海洋的情况。这些模型将测试这种情况是否可以解释古代地球磁场的产生。虽然我们将直接了解地球深处的内部，但这项工作也会影响我们对表面过程的理解，因为针对地球的高电荷粒子的磁屏蔽（或缺乏磁屏蔽）将影响地球的大气和表面。

The magnetic field of the Earth, generated inside the fluid portion of Earth's Iron core, protects the Earth and orbiting satellites from a barrage of potentially harmful charged particles streaming through space. The magnetization of ancient rocks has shown us that the magnetic field has been shielding Earth for at least 3.5 billion years. Beyond that age, there are no observations currently available to assess if a magnetic field was present. It is a mystery when exactly the magnetic field arose, and also a challenging puzzle as to how it has been sustained for billions of years. The answers to those questions will greatly impact our understanding of how our Earth evolved from its initial state into a habitable planet able to develop and sustain life on its surface. The proposed research aims to take a new approach to answer these difficult questions by looking at the role a deep magma ocean overlying Earth's core might have played in helping sustain an ancient magnetic field. Recent experiments that are able to simulate the extreme pressures and temperatures within Earth's deep interior have provided new knowledge on how Earth materials behave under such conditions. Using this recently gained information on material properties, in conjunction with theoretical considerations of the energetics of magnetic field generation, this project will build physics-based models of Earth's interior and cooling through time. These efforts will specifically investigate scenarios in which there is a long-lived magma ocean on top of the core. These models will test if this scenario can explain the generation of Earth's magnetic field during ancient times. While we will learn directly about the Earth's deep interior, this work impacts our understanding of surface processes as well, since the magnetic shielding of highly charged particles aimed at Earth (or lack thereof) will affect the atmosphere and surface of the Earth.