Magnetopause ripples going against the flow form azimuthally stationary surface waves.
Magnetopause ripples going against the flow form azimuthally stationary surface waves.
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磁层顶的波纹与气流方向相反，形成方位稳定的表面波。
DOI：
10.1038/s41467-021-25923-7
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发表时间：
2021-10-06
影响因子：
16.6
通讯作者：
Rastaetter L
中科院分区：
文献类型：
--
作者：
Archer MO;Hartinger MD;Plaschke F;Southwood DJ;Rastaetter L
表面波处理湍流扰动，这些扰动驱动许多空间、天体物理和实验室等离子体系统的动态，而地球磁层的外边界，即磁层顶，为研究它们提供了一个可访问的环境。磁层顶表面波被认为像水面上的波浪一样，沿着驱动太阳风的方向传播，因此，在全球磁层动力学中，尾向传播的范例已经得到了很好的建立。在这里，我们通过多航天器观测，全球模拟和分析理论表明，最低频率的脉冲激发磁层顶表面波，与常设结构沿着地磁场，逆着边界外的流动传播。在很宽的当地时间范围内（09- 15小时），波的坡印廷通量精确地平衡了气流的平流效应，导致没有净能量通量，因此也有稳定的结构穿过场。然而，在赤道两侧，平流占主导地位，因此波向下传播，在共振频率下播种波动，随后通过开尔文-亥姆霍兹不稳定性增加振幅，并耦合到磁层体波。这种全球性的反应，与公认的范式相反，辐射带，电离层和极光动力学和其他动力系统的潜在应用的影响。驱动全球等离子体动力学的磁层顶表面波（SW）被认为像水面上的波浪一样，与驱动太阳风一起传播。在这里，作者表明，脉冲激发SW，与常设结构沿着地磁场，是静止的传播对这个流。
Surface waves process the turbulent disturbances which drive dynamics in many space, astrophysical and laboratory plasma systems, with the outer boundary of Earth’s magnetosphere, the magnetopause, providing an accessible environment to study them. Like waves on water, magnetopause surface waves are thought to travel in the direction of the driving solar wind, hence a paradigm in global magnetospheric dynamics of tailward propagation has been well-established. Here we show through multi-spacecraft observations, global simulations, and analytic theory that the lowest-frequency impulsively-excited magnetopause surface waves, with standing structure along the terrestrial magnetic field, propagate against the flow outside the boundary. Across a wide local time range (09–15h) the waves’ Poynting flux exactly balances the flow’s advective effect, leading to no net energy flux and thus stationary structure across the field also. Further down the equatorial flanks, however, advection dominates hence the waves travel downtail, seeding fluctuations at the resonant frequency which subsequently grow in amplitude via the Kelvin-Helmholtz instability and couple to magnetospheric body waves. This global response, contrary to the accepted paradigm, has implications on radiation belt, ionospheric, and auroral dynamics and potential applications to other dynamical systems. The magnetopause surface waves (SW) that drive global plasma dynamics are thought, like waves on water, to travel with the driving solar wind. Here, the authors show that impulsively-excited SW, with standing structure along the geomagnetic field, are stationary by propagating against this flow.
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影响因子：
2.8
作者：
BERCHEM, J;RUSSELL, CT
通讯作者：
RUSSELL, CT
影响因子：
2.8
作者：
Elsden, T.;Wright, A. N.
通讯作者：
Wright, A. N.
影响因子：
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作者：
Eriksson, P. T. I.;Blomberg, L. G.;Glassmeier, K. -H.
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Glassmeier, K. -H.
影响因子：
2.8
作者：
Archer, M. O.;Plaschke, F.
通讯作者：
Plaschke, F.
影响因子：
2.9
作者：
FRITSCH, FN;CARLSON, RE
通讯作者：
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