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arXiv 2107.04511physics.space-phastro-ph.EPphysics.plasm-ph
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行星际激波诱导磁层顶运动:理论与全球磁流体动力学模拟的比较

Interplanetary Shock-induced Magnetopause Motion: Comparison between Theory and Global Magnetohydrodynamic Simulations

Ravindra T. Desai, Mervyn P. Freeman, Jonathan P. Eastwood, Joseph. W. B. Eggington, Martin. O. Archer, Yuri Shprits, Nigel P. Meredith, Frances A. Staples, I. … 展开作者

Ravindra T. Desai, Mervyn P. Freeman, Jonathan P. Eastwood, Joseph. W. B. Eggington, Martin. O. Archer, Yuri Shprits, Nigel P. Meredith, Frances A. Staples, I. Jonathan Rae, Heli Hietala, Lars Mejnertsen, Jeremy P. Chittenden, Richard B. Horne

摘要:

磁层顶是地球磁层的外缘,也是太阳风和磁层等离子体之间的明显边界。在这封信中,我们使用全球磁流体动力学模拟来研究地球磁层顶的快速前进行星际冲击的各种强度的响应,并比较理论预测。理论和模拟表明,磁层顶的响应可以由三个不同的阶段,初始加速的惯性力被克服,一个快速的压缩阶段,包括大部分的行程,和大规模的阻尼振荡的振幅的地球半径的顺序。这两种方法在预测频率为2-13 mHz的太阳下磁层顶振荡方面一致,但模拟结果明显预测了更大的振幅和更弱的阻尼率。这一现象与空间天气预报密切相关,并为1972年8月和1991年3月发生大的行星际冲击之后观测到的磁层顶振荡提供了一种可能的解释。

英文摘要:

The magnetopause marks the outer edge of the Earth's magnetosphere and a distinct boundary between solar wind and magnetospheric plasma populations. In this letter, we use global magnetohydrodynamic simulations to examine the response of the terrestrial magnetopause to fast-forward interplanetary shocks of various strengths and compare to theoretical predictions. The theory and simulations indicate the magnetopause response can be characterised by three distinct phases; an initial acceleration as inertial forces are overcome, a rapid compressive phase comprising the majority of the distance travelled, and large-scale damped oscillations with amplitudes of the order of an Earth radius. The two approaches agree in predicting subsolar magnetopause oscillations with frequencies 2-13 mHz but the simulations notably predict larger amplitudes and weaker damping rates. This phenomenon is of high relevance to space weather forecasting and provides a possible explanation for magnetopause oscillations observed following the large interplanetary shocks of August 1972 and March 1991.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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