Chen Li-Jen, Ng Jonathan, Omelchenko Yuri, Wang Shan
NASA Goddard Space Flight Center Greenbelt MD USA.
University of Maryland College Park MD USA.
Geophys Res Lett. 2021 Jun 16;48(11):e2021GL093029. doi: 10.1029/2021GL093029. Epub 2021 May 31.
Based on global hybrid simulation results, we predict that foreshock turbulence can reach the magnetopause and lead to reconnection as well as Earth-sized indents. Both the interplanetary magnetic field (IMF) and solar wind are constant in our simulation, and hence, all dynamics are generated by foreshock instabilities. The IMF in the simulation is mostly Sun-Earth aligned with a weak northward and zero dawn-dusk component, such that subsolar magnetopause reconnection is not expected without foreshock turbulence modifying the magnetosheath fields. We show a reconnection example to illustrate that the turbulence can create large magnetic shear angles across the magnetopause to induce local bursty reconnection. Magnetopause reconnection and indents developed from the impact of foreshock turbulence can potentially contribute to dayside loss of planetary plasmas.
基于全球混合模拟结果，我们预测前震湍流能够到达磁层顶并导致重联以及形成地球大小的凹陷。在我们的模拟中，行星际磁场（IMF）和太阳风都是恒定的，因此，所有动力学都是由前震不稳定性产生的。模拟中的行星际磁场大多与日地连线对齐，北向分量较弱，晨昏分量为零，这样在没有前震湍流改变磁鞘场的情况下，预计不会发生日下点磁层顶重联。我们展示了一个重联实例，以说明湍流能够在磁层顶产生大的磁剪切角，从而诱发局部突发重联。由前震湍流的影响而产生的磁层顶重联和凹陷可能会导致行星等离子体向日侧流失。
