Anelastic torsional oscillations in Jupiter's metallic hydrogen region
Anelastic torsional oscillations in Jupiter's metallic hydrogen region
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木星金属氢区域的滞弹性扭转振荡
DOI：
10.1016/j.epsl.2019.04.042
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发表时间：
2019
影响因子：
5.3
通讯作者：
Hori K
中科院分区：
文献类型：
--
作者：
Hori K
我们考虑扭转阿尔文波，这可能是激发在木星的金属氢区域。这些轴对称的纬向流波动先前已被检查的不可压缩流体的背景下，地球的液态铁芯。在平衡模型中实现密度和电导率径向变化的深层木星发电机的理论模型再现了其强大的偶极磁场。分析这样的模型，我们发现滞弹性扭转波旅行垂直于旋转轴在金属区域的时间尺度上至少几年。在发电机区域的外部，由于受到更剧烈的对流的激发，它们可以向内和向外传播。当在过渡到分子区域的磁性切向圆柱体上反射时，它们可以形成驻波。在观测数据中识别这种反射可以确定金属区域有效开始的深度。此外，这也可以将木星的扭转波与地核的扭转波区分开来，在地核中，观测证据表明波主要从旋转轴向外传播。这些波可以传输角动量，并可能引起木星自转周期的变化，幅度不超过几十毫秒。此外，这些内部扰动可能会引起10%的变化，随着时间的推移，在纬向流在3000公里的深度以下的表面。
We consider torsional Alfvén waves which may be excited in Jupiter's metallic hydrogen region. These axisymmetric zonal flow fluctuations have previously been examined for incompressible fluids in the context of Earth's liquid iron core. Theoretical models of the deep-seated Jovian dynamo, implementing radial changes of density and electrical conductivity in the equilibrium model, have reproduced its strong, dipolar magnetic field. Analysing such models, we find anelastic torsional waves travelling perpendicular to the rotation axis in the metallic region on timescales of at least several years. Being excited by the more vigorous convection in the outer part of the dynamo region, they can propagate both inwards and outwards. When being reflected at a magnetic tangent cylinder at the transition to the molecular region, they can form standing waves. Identifying such reflections in observational data could determine the depth at which the metallic region effectively begins. Also, this may distinguish Jovian torsional waves from those in Earth's core, where observational evidence has suggested waves mainly travelling outwards from the rotation axis. These waves can transport angular momentum and possibly give rise to variations in Jupiter's rotation period of magnitude no greater than tens of milliseconds. In addition these internal disturbances could give rise to a 10% change over time in the zonal flows at a depth of 3000 km below the surface.
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DOI：
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发表时间：
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期刊：
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影响因子：
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