A geodynamo powered by luni-solar precession
A geodynamo powered by luni-solar precession
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由日月进动驱动的地球发电机
DOI：
10.1080/03091929108227780
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发表时间：
1991
影响因子：
1.3
通讯作者：
J. Vanyo
中科院分区：
文献类型：
--
作者：
J. Vanyo
摘要 在模拟地幔受日月引力强迫进动的实验室实验以及一个简化的解析液体流动模型中，对充满液体的扁球体腔的受控自旋和进动的研究表明，地球核心的流动近似为绕核心轴的自旋，该轴滞后于地幔进动的自旋轴一个小角度（约0.01°）。核心自旋比地幔自旋慢的量与磁场的西向漂移相符（约0.2°/年）。理论和实验证据都表明惯性波在阻止这种运动方面是无效的。这种进动流模型与地球发电机的要求相符，表明在运动学上优于磁流体动力学发电机，因为粘性的核 - 幔耦合可能主导磁耦合，而地形耦合可忽略不计。虽然该模型似乎满足地球发电机的要求，但它并不排除同时存在密度梯度对流机制。
Abstract Controlled spin and precession of liquid filled oblate spheroidal cavities in laboratory experiments that simulate luni-solar forced precession of the mantle and a simplified analytical liquid flow model, indicate Earth core flows approximated as spin about a core axis that lags behind the precessing spin axis of the mantle by a small angle (∼0·01°). Core spin is slower than mantle spin by an amount consistent with westward drift of the magnetic field (∼0·2°/yr). Theoretical and experimental evidence argue against inertia waves being effective in preventing such motion. This precessional flow model is consistent with geodynamo requirements indicating a kinematic over a magnetohydrodynamic dynamo in that viscous core-mantle coupling may dominate magnetic coupling, with only negligible topographic coupling. While the model appears to provide geodynamo requirements, it does not preclude simultaneous density gradient convective mechanisms.