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首页> 外文期刊>The Astrophysical journal >NON-AXISYMMETRIC FLOWS ON HOT JUPITERS WITH OBLIQUE MAGNETIC FIELDS
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NON-AXISYMMETRIC FLOWS ON HOT JUPITERS WITH OBLIQUE MAGNETIC FIELDS

机译:具有倾斜磁场的热耦合器上的非轴对称流动

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Giant planets that reside in close proximity to their host stars are subject to extreme irradiation, which gives rise to thermal ionization of trace alkali metals in their atmospheres. On objects where the atmospheric electrical conductivity is substantial, the global circulation couples to the background magnetic field, inducing supplementary fields and altering the nature of the flow. To date, a number of authors have considered the influence of a spin-pole aligned dipole magnetic field on the dynamical state of a weakly ionized atmosphere and found that magnetic breaking may lead to significantly slower winds than predicted within a purely hydrodynamical framework. Here, we consider the effect of a tilted dipole magnetic field on the circulation and demonstrate that in addition to regulating wind velocities, an oblique field generates stationary non-axisymmetric structures that adhere to the geometry of the magnetic pole. Using a kinematic perturbative approach, we derive a closed-form solution for the perturbed circulation and show that the fractional distortion of zonal jets scales as the product of the field obliquity and the Els?sser number. The results obtained herein suggest that on planets with oblique magnetic fields, advective shifts of dayside hotspots may have substantial latitudinal components. This prediction may be tested observationally using the eclipse mapping technique.
机译:居住在靠近其恒星的巨型行星会受到极端辐射,这会导致大气中的痕量碱金属发生热电离。在大气电导率很高的物体上,整体环流耦合到背景磁场,从而感应出补充磁场并改变了流动的性质。迄今为止,许多作者已经考虑了自旋极对准偶极子磁场对弱电离大气层动力学状态的影响,并发现磁性破裂可能导致风速比纯流体力学框架中预测的慢得多。在这里,我们考虑了倾斜偶极子磁场对循环的影响,并证明了除了调节风速之外,倾斜磁场还会产生固定的非轴对称结构,该结构会附着在磁极的几何形状上。使用运动学摄动法,我们得出了扰动环流的封闭形式解,并证明了纬向射流的分数畸变是视场倾角和Elsssser数的乘积。本文获得的结果表明,在具有倾斜磁场的行星上,日间热点的对流移动可能具有较大的纬向分量。可以使用日食映射技术观察性地测试此预测。

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