Combined dynamical and morphological characterisation of geodynamo simulations
Combined dynamical and morphological characterisation of geodynamo simulations
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地球发电机模拟的组合动力学和形态表征
DOI：
10.1016/j.epsl.2022.117752
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发表时间：
2022
影响因子：
5.3
通讯作者：
Nakagawa T
中科院分区：
文献类型：
--
作者：
Nakagawa T
数值发电机模拟不能在地球核心的物理条件下运行，但它们经常产生与现在的地磁场在形态上相似的场。因此，一个关键问题是要破译在什么条件下可以实现“类地球”模拟。最近的工作表明，一组模拟进行沿着一个特定的路径在参数空间顺利地接近QG-MAC动力学，预计在地球的核心，从而领先的订单力平衡是准地转与磁，阿基米德和科里奥利力平衡在一阶。然而，QG-MAC平衡和模拟领域的形态特征之间的系统联系尚未建立。在这里，我们评估了一套67模拟使用既定的遵守标准的领域形态和规模依赖的力平衡，以量化的内部动态。形态符合现代地磁场并不意味着一个单一的基本力平衡，反之亦然，然而，大多数兼容的模拟，包括所有接近现实值的磁ReynoldsnumberRm，在QG-MAC平衡。模拟，同时实现良好的形态符合地球的现代领域，QG-MAC平衡，和高Rm，被限制在一个中间范围的偶极（在偶极场的能量比截断在12度的外边界的能量）。在此偶极范围内的反向模拟在极性转变期间保持主导QG-MAC平衡，尽管惯性对力平衡做出不可忽略的贡献。
Numerical dynamo simulations cannot operate at the physical conditions of Earth's core, yet they often produce fields that appear morphologically similar to the present geomagnetic field. A key issue is therefore to decipher under what conditions “Earth-like” simulations can be achieved. Recent work has shown that a set of simulations undertaken along a specific path in parameter space smoothly approach the QG-MAC dynamics that are expected in Earth's core, whereby the leading order force balance is Quasi-Geostrophic with Magnetic, Archimedean and Coriolis forces equilibrating at first order. However, a systematic link between QG-MAC balance and morphological features of the simulated fields has yet to be established. Here we assess a suite of 67 simulations using established compliance criteria for the field morphology and scale-dependent force balances to quantify the internal dynamics. Morphological compliance with the modern geomagnetic field does not imply a single underlying force balance or vice versa; however, the majority of compliant simulations, including all those approaching a realistic value of the magnetic Reynolds numberRm, are in QG-MAC balance. Simulations that simultaneously achieve excellent morphological compliance with Earth's modern field, QG-MAC balance, and highRm, are confined to an intermediate range of dipolarity (the ratio of energy in the dipole field to the energy truncated at degree 12 at the outer boundary). Reversing simulations in this dipolarity range maintain dominant QG-MAC balance during polarity transition, though inertia makes a non-negligible contribution to the force balance.
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影响因子：
3.7
作者：
E. Dormy;J. Valet;V. Courtillot
通讯作者：
V. Courtillot
由于最下地幔的高电导，太平洋上的弱磁场发生变化
影响因子：
18.3
作者：
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通讯作者：
C. More
影响因子：
5.3
作者：
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通讯作者：
Panovska, Sanja
核心内的大规模流动
DOI：
--
发表时间：
2007
期刊：
影响因子：
--
作者：
R. Holme
通讯作者：
R. Holme
DOI：
--
发表时间：
2011
期刊：
影响因子：
--
作者：
R. Holme;N. Olsen;F. Bairstow
通讯作者：
F. Bairstow