Geomagnetic Dynamo Theory

这个项目的目的是用一种新的数值方法来整合地球发电机的三维模型。与大多数目前的研究一样，地球的流体核心将由对流的Boussinesq流体表示。传统的数值方法不能以许多个数量级来模拟巨大的旋转(科里奥利力)力的影响，这种力如此强烈地影响着核心的对流制度；新的方法承诺在一个数量级内表示它们。这一新程序依赖于一种不同寻常的计算网格选择，已经在所谓的地球发电机“中间模型”上进行了测试，这些模型是对核心磁流体动力学(MHD)的轴对称过度理想化，并被发现执行得很好。下一个合乎逻辑的步骤是包括地球物理现实(即动态确定的)不对称性。新的整合有望有助于解决这十年来地球发电机理论的核心问题之一：核心的MHD是否受控于核-地幔边界。

The purpose of this project is to integrate a three- dimensional model of the geodynamo by using a novel numerical method. In common with most current research, the Earth's fluid core will be represented by a convecting Boussinesq fluid. Traditional numerical methods cannot, by many orders of magnitude, simulate the effects of the large rotational (Coriolis) force that so potently affects the convective regime of the core; the new method promises to represent them within an order of magnitude. The new procedure, which depends on an unusual choice of computational grid, has been tested on so- called "intermediate models" of the geodynamo, which are axisymmetric over-idealizations of the magnetohydrodynamics (MHD) of the core, and has been found to perform well. The next logical step is to include geophysically realistic (i.e. dynamically determined) asymmetries. The new integrations will hopefully help settle one of the central issues of geodynamo theory of this decade: whether or not the MHD of the core is controlled at the core-mantle boundary.