CMG Research: Collaborative Research: Models of Sub-Grid Scale Turbulence in Earth's Core and the Geodynamo

EAR-0222334保罗·H·罗伯茨地球发电机负责地球磁场，是一个涉及广泛相互作用的尺度、复杂的几何形状和丰富的各种物理过程的地球系统。数值模拟只解决最大尺度的特征；大多数较小的次网格尺度过程的参数化只模拟耗散过程，不能模拟影响不同空间尺度之间能量传递的非耗散过程。这一说法的例外是最近开发的相似模型和纳维-斯托克斯-阿尔法模型。岩心动力学受到科里奥利力和洛伦兹力的强烈影响，使得磁场既是各向异性的，又是非局部的。最近的研究为这些过程提供了有价值的见解，这将有助于推动准确解释这些力量的通用模型。该项目将通过将小尺度场结构的知识纳入相似性模型和纳维-斯托克斯-阿尔法模型，开发更好的地心亚格网过程的参数。该项目将涉及数值模拟和理论分析的结合，不仅采用分离物理过程和分析问题的简化模型，而且还采用现实的地球发电机模型。这项研究将由一组来自美国机构和国外的数学家和地球科学家在一个管理小组的监督下进行。该项目将促进发电机集体成员之间的互动，预计将由该项目组织和部分支助的年度讲习班将产生进一步的合作。预期旋转磁对流中次网格过程的改进的参数化将使所有希望研究其他行星和恒星中的磁力和发电机的人感兴趣。相信这些人中的许多人都希望参加计划中的讲习班。寻求量化地球内部结构、动力学和历史的第二批地球科学家和数学家将对改进的地球发电机数值模型感兴趣。

EAR-0222334Paul H. Roberts Earth's dynamo, which is responsible for the geomagnetic field, is a geosystem involving a broad range of interacting scales, a complex geometry and a rich variety of physical processes. Numerical simulations resolve only the largest-scale features; most parameterizations of the smaller, subgrid scale processes simulate dissipative processes only, and are incapable of simulating non-dissipative processes which affect transfers of energy among differing spatial scales. Exceptions to this statement are the recently developed similarity and Navier-Stokes-alpha models. Core dynamics is strongly affected by the action of the Coriolis and Lorentz forces, making the fields both anisotropic and non-local. Recent studies have provided valuable insight into these processes, which will help motivate generalized models that accurately account for these forces. This project will develop better parameterizations of subgrid processes in Earth's core by incorporating into the similarity and Navier-Stokes-alpha models, knowledge of the structure of the small-scale fields. The project will involve a combination of numerical simulation and theoretical analysis employing not only simplified models that isolate physical processes and analytical issues, but also realistic geodynamo models. The research will be undertaken by a group of mathematicians and geoscientists from US institutions and from abroad under the supervision of a management group. The project will foster interactions between members of the dynamo collective, and it is expected that further collaborations will result from the annual workshops that will be organized and partially supported by the project. It is anticipated that improved parameterization of subgrid processes in rotating magnetoconvection will interest all who wish to study magnetism and dynamos in other planets and in stars. It is believed that many of these people will wish to participate in the planned workshops. An improved numerical model of the geodynamo will be of interest to a second group of geoscientists and mathematicians who seek to quantify the structure, dynamics and history of the interior of our planet.--