EAR-PF: Thermochemical Convection Dynamics in Earth's Core

Michael a . Calkins博士被授予美国国家科学基金会地球科学博士后奖学金，在科罗拉多大学博尔德分校开展一项研究和教育计划。这项研究将采用计算效率高的二维数值模拟来提高我们对地球液态外核热化学对流动力学的理解。这项工作的目标是确定当热浮力和化学浮力同时存在时，地核的动力学是如何变化的，产生的流体对热扩散率和化学扩散率的敏感性，以及动力学是如何随着地球的缓慢冷却而随时间变化的。这些结果对于帮助理解地球磁场的结构和维持磁场的发电机过程是至关重要的。人们普遍认为，地球的磁场是由熔融铁的外核中的流体运动产生的。然而，这种“发电机”过程仍然是地球科学中最不为人所知的现象之一。这个项目将使用计算机模拟来研究岩心内的流体运动。这项研究将对提高我们对发电机机制和核心演化的理解至关重要。此外，这些结果将广泛适用于发生类似流体运动的地球科学的其他领域，如地幔、海洋和岩浆室。Calkins博士将教授一学期的地球科学流体运动建模课程，以吸引数学和物理科学领域的本科生和研究生。本课程的目标是让每位学生设计并在多处理器机器上运行计算流体动力学代码。学生将学习理解和模拟地球科学中无处不在的流体流动现象所需的基本技能。

Dr. Michael A. Calkins has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out a research and education plan at the University of Colorado, Boulder. This investigation will employ computationally efficient two-dimensional numerical simulations to improve our understanding of thermochemical convection dynamics in the Earth's liquid outer core. The goal of this work is to determine how the dynamics of the core change when both thermal and chemical buoyancy are present, the sensitivity of the resulting flow to the value of the thermal and chemical diffusivities, and how the dynamics have changed over time in response to the slow cooling of the Earth. The results will be fundamental for helping to understand the structure of the Earth's magnetic field and the dynamo process by which it is maintained. It is widely believed that the Earth's magnetic field is generated by fluid motion in the molten iron outer core. However, this "dynamo" process remains one of the least understood phenomena in the Earth sciences. This project will use computer simulations to investigate the fluid motions within the core. The research will be crucial for improving our understanding of the dynamo mechanism and the evolution of the core. Furthermore, the results will be broadly applicable to other areas of the Earth sciences where similar fluid motions occur, such as the Earth's mantle, oceans, and magma chambers. Dr. Calkins will engage a diverse body of undergraduate and graduate students in the mathematical and physical sciences by teaching a semester-long course on modeling fluid motion in the Earth sciences. The goal of the course is for each student to design and run a computational fluid dynamics code on multi-processor machines. Students will learn the fundamental skills required to understand and model the fluid flow phenomena that are ubiquitous in the Earth sciences.