Magnetic instabilities in rapidly rotating spherical geometries II. more realistic fields and resistive instabilities
Magnetic instabilities in rapidly rotating spherical geometries II. more realistic fields and resistive instabilities
复制标题
快速旋转的球形几何形状中的磁不稳定性 II。
DOI：
10.1080/03091929108220008
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发表时间：
1991
影响因子：
1.3
通讯作者：
W. Weiglhofer
中科院分区：
文献类型：
--
作者：
D. Fearn;W. Weiglhofer
磁不稳定性在理解地球流体核动力学中起着重要作用。本文继续研究了具有环形基态的快速旋转的刚性电绝缘球形几何中导电流体的线性稳定性，其中包括磁场BMB O（r，θ）1 θ和流动UMU O（r，θ）1 θ。本文采用磁旋近似数值分析了可能与地球有关的两类不稳定性。这些是场梯度（或理想）不稳定性，这需要强场梯度和强场，以及电阻不稳定性，取决于有限电阻率和基态B O（r，θ）中存在零。在本系列的第一篇论文中，我们根据圆柱几何中的局部分析和数值结果，对非常简单的基态，建立了球几何中场梯度不稳定性的存在性。在这里，我们扩展了C…
Abstract Magnetic instabilities play an important role in the understanding of the dynamics of the Earth's fluid core. In this paper we continue our study of the linear stability of an electrically conducting fluid in a rapidly rotating, rigid, electrically insulating spherical geometry in the presence of a toroidal basic state, comprising magnetic field BMB O(r, θ)1⊘ and flow UMU O(r, θ)1⊘ The magnetostrophic approximation is employed to numerically analyse the two classes of instability which are likely to be relevant to the Earth. These are the field gradient (or ideal) instability, which requires strong field gradients and strong fields, and the resistive instability, dependent on finite resistivity and the presence of a zero in the basic state B O(r,θ). Based on a local analysis and numerical results in a cylindrical geometry we have established the existence of the field gradient instability in a spherical geometry for very simple basic states in the first paper of this series. Here, we extend the c...