Numerical Modeling of Magnetohydrodynamic Convection in a Rapidly Rotating Spherical Shell
Numerical Modeling of Magnetohydrodynamic Convection in a Rapidly Rotating Spherical Shell
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DOI：
10.1006/jcph.1999.6274
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发表时间：
1999-07
影响因子：
4.1
通讯作者：
W. Kuang;J. Bloxham
中科院分区：
文献类型：
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作者：
W. Kuang;J. Bloxham
在本文中，我们描述了一个数值模型，调查磁流体动力学（MHD）对流的Boussinesq流体在一个快速旋转的球壳，驱动的浮力所产生的传入的浮力通量在内核边界。该模型的目的是研究地球流体外核磁场的产生。我们的模型不同于G. A. Glatzmaier和P. H.罗伯茨，谁最近调查了这个问题，在几个方面。我们应用不同的物理近似力平衡的系统：而不是粘性应力，我们使用一个轴对称的惯性力来平衡所产生的洛伦兹力的轴向磁转矩;我们使用一个混合的光谱？有限差分算法，更好地并行化的代码;并适用于不同的边界条件。我们详细描述了我们的数值模型，我们测试它通过检查纯粹的热对流在一个快速旋转的流体壳，并通过检查库马尔？罗伯茨运动发电机（修改为球壳）。我们的结果与以前的研究结果一致。我们还提出了一个弱场发电机解决方案在一个非常简化的系统和强场发电机解决方案在一个更现实的系统。
In this paper we describe a numerical model for investigating magnetohydrodynamic (MHD) convective flow of a Boussinesq fluid in a rapidly rotating spherical shell, driven by the buoyancy forces arising from incoming buoyant flux at the inner core boundary. The model is designed to investigate the generation of magnetic field in the Earth's fluid outer core. Our model differs from that of G. A. Glatzmaier and P. H. Roberts, who have recently investigated this problem, in several aspects. We apply a different physical approximation in the force balance of the system: instead of viscous stress, we use an axisymmetric inertial force to balance the axial magnetic torque arising from the Lorentz force; we use a mixed spectral?finite difference algorithm for better parallelization of the code; and apply different boundary conditions. We describe our numerical model in detail, and we test it by examining purely thermal convection in a rapidly rotating fluid shell and by examining Kumar?Roberts kinematic dynamos (modified for the spherical shell). Our results agree well with those of the previous studies. We also present a weak-field dynamo solution in a very simplified system and strong-field dynamo solutions in a more realistic system.