Next-Generation Modeling of the Geodynamo: Development of the First Multi-Scale Dynamo Model

下一代地球发电机建模：第一个多尺度发电机模型的开发

• 批准号: 1320991
• 负责人: Keith Julien
• 金额: $ 54万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1320991&HistoricalAwards=false
• 关键词: Next; Generation; Modeling; Geodynamo; Development

The Earth's magnetic field is now known to be the result of fluid motion within the Earth's molten iron outer core. This "dynamo" process remains one of the least understood phenomena in the Earth sciences, however, due to the lack of direct observations. Computer simulations have proven to be valuable tools for advancing our understanding of dynamos. Nevertheless, it is not currently possible to capture all the temporal and spatial scales of dynamical relevance in the Earth's core given modern-day technological constraints. The PIs are overcoming these limitations by developing the first multi-scale mathematical model of the geodynamo. In this respect, the proposed work can be viewed as a new computational and modeling framework that will allow for the highest resolution simulations of the Earth's core to date. Additionally, these methods will be broadly applicable to a range of other scientific problems ranging from molecular physics to cellular dynamics.Three-dimensional numerical simulations have vastly improved our understanding of convection driven dynamos, yet computational constraints currently limit them to physical parameters that are distant from those that characterize the Earth's liquid outer core. This fact highlights a serious gap in our understanding of the geodynamo, and severely limits our ability to relate directly geomagnetic field observations and the output of numerical dynamo models. The proposed work will, for the first time, employ the methodology of multiple scale asymptotics to planetary dynamo systems for purpose of developing a model that is capable of reaching parameter values and physical properties of Earth's core. In this way, the asymptotic regime of the proposed model will provide a more complete understanding of geomagnetic field observations. Findings of the research will be directly applicable to other rapidly rotating, turbulent fluid systems on and within stars, extrasolar planets, and the other planets within the Solar System. Moreover, the mathematical methods employed for development of the reduced equations are broadly applicable to a range of other scientific problems ranging from molecular physics to cellular dynamics.

现在已知地球的磁场是地球熔融铁外芯内流体运动的结果。 由于缺乏直接观察，这种“发电机”过程仍然是地球科学中最知名的现象之一。 事实证明，计算机模拟是提高我们对发电机的理解的宝贵工具。 然而，考虑到现代技术限制，目前不可能捕获地球核心中动态相关性的所有时间和空间尺度。 PI通过开发Geodynamo的第一个多尺度数学模型来克服这些局限性。在这方面，拟议的工作可以被视为一种新的计算和建模框架，该框架将允许迄今为止对地球核心的最高分辨率模拟。 此外，这些方法将广泛地适用于从分子物理到细胞动力学的一系列其他科学问题。三维数值模拟极大地改善了我们对对流驱动的元分的理解，但目前的计算限制将它们限制在与地球液体外部核心那些远距离的物理参数上。 这一事实强调了我们对地球怪物的理解的严重差距，并严重限制了我们直接关联地磁场观测值和数值发电机模型的输出的能力。 拟议的工作将首次采用多个尺度渐进剂的方法对行星发电机系统进行，目的是开发能够达到地球核心的参数值和物理性质的模型。 通过这种方式，提出的模型的渐近状态将提供对地磁野外观测的更完整理解。 该研究的发现将直接适用于其他快速旋转的，恒星，极地球外行星和太阳系中其他行星的迅速旋转，湍流系统。 此外，用于开发还原方程的数学方法广泛地适用于从分子物理学到细胞动力学的一系列其他科学问题。