Investigations of the Geodynamo

了解地球磁场的起源并预测其未来的演化是地球科学中的关键问题之一。虽然目前普遍认为磁场是由地球流体(主要是铁)中的流体发电机作用来维持的，但对这一过程的细节了解很少。本项目有以下具体目标：1.在最近的地球发电机数值模型中研究磁场产生的基本机制。研究发电机数值模型的参数模式，特别是寻求进一步了解惯性和粘性效应对发电机的作用。研究热核-地幔相互作用及其对主场形态及其长期变化的控制作用。研究了内核重力耦合对地球动力学的影响。使用发电机数值模型分析在核-地幔边界的磁场图中观察到的特征。分析冻结通量近似，在足够短的时间尺度下，磁场可以被认为是冻结在流体中的假设。开发发电机代码，包括开发适合在基于商用硬件的机器网络上运行的代码的分布式存储版本，以便利用这种硬件的性价比。这项工作的结果不仅将通过传统的科学出版渠道传播，而且还将通过非传统渠道的电视纪录片传播，以确保在研究界之外传播。此外，调查结果将纳入首席调查员的教材中。

Understanding the origin of the Earth's magnetic field and predicting its future evolution is one of the key problems in the Earth sciences. While it is nowadays almost universally accepted that the magnetic field is maintained by hydromagnetic dynamo action in the Earth's fluid, predominantly iron, outer core, the details of that process remain very poorly understood.This project has the following specific aims:1. Investigation of the basic underlying mechanisms of magnetic field generation in recentnumerical models of the geodynamo.2. Investigation of the parameter regime of numerical dynamo models, seeking in particularto further our understanding of the role of inertial and viscous effects on the dynamo.3. Investigation of thermal core-mantle interactions and their role in controlling the morphology of the main field and its secular variation.4. Investigation of the effect of inner core gravitational coupling on the geodynamo.5. Analysis of features observed in maps of the magnetic field at the core-mantle boundaryusing a numerical dynamo model.6. Analysis of the frozen flux approximation, the assumption under which on sufficiently short timescales the magnetic field can be considered to be frozen into the fluid.7. Dynamo code development, including development of a distributed memory version of the code suitable for running on a network of commodity-hardware based machines in order to take advantage of the performance-cost ratio of such hardware.The results of this work will be disseminated not only through traditional channels of scientific publication but additionally through non-traditional channels television documentaries to ensure dissemination beyond the research community. Additionally, the results will be incorporated into the Principal Investigator's teaching materials.