Giant vortices lead to ion escape from Venus and re-distribution of plasma in the ionosphere
Giant vortices lead to ion escape from Venus and re-distribution of plasma in the ionosphere
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DOI：
10.1029/2008gl036977
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发表时间：
2009-04-15
影响因子：
5.2
通讯作者：
Barabash, S.
中科院分区：
文献类型：
--
作者：
Pope, S. A.;Balikhin, M. A.;Barabash, S.
太阳风与金星的相互作用对金星大气的演变有着重要的影响。由于缺乏固有的行星磁场，在快速流动的太阳风和金星电离层之间有直接接触。这导致了许多不同类型的大气逃逸过程。通过金星快车的观测，我们发现这种接触导致了金星弓形激波下游全球涡旋的形成。这些漩涡加速了电离层中的重离子，如氧，导致它们逃逸。我们认为这些涡旋是由太阳风和电离层等离子体边界的剪切速度曲线激发的开尔文-亥姆霍兹不稳定性的结果。在太阳活动极小期，当电离层从白天到晚上的流动受到终结点处电离层顶高度降低的限制时，这些涡旋也有助于在夜间重新填充电离层。引用本文：Pope， S. A.， M. A. Balikhin， T. L. Zhang， A. O. Fedorov， M. Gedalin， S. Barabash(2009)，巨型漩涡导致金星离子逸出和电离层等离子体的重新分布，地球物理学报。卷。， 36, L07202, doi: 10.1029/2008GL036977。
The interaction of the solar wind with Venus has a significant influence on the evolution of its atmosphere. Due to the lack of an intrinsic planetary magnetic field, there is direct contact between the fast flowing solar wind and the Venusian ionosphere. This leads to a number of different types of atmospheric escape process. Using Venus Express observations, we show that such contact leads to the formation of global vortices downstream of the Venusian bow shock. These vortices accelerate heavy ionospheric ions such as oxygen, leading to their escape. We argue that these vortices are the result of the Kelvin-Helmholtz instability excited by the shear velocity profile at the boundary between the solar wind and ionospheric plasma. These vortices also help to repopulate the night-side ionosphere during solar minimum, when the ionospheric flow from day to night is restricted by the lowered ionopause altitude at the terminator. Citation: Pope, S. A., M. A. Balikhin, T. L. Zhang, A. O. Fedorov, M. Gedalin, and S. Barabash (2009), Giant vortices lead to ion escape from Venus and re-distribution of plasma in the ionosphere, Geophys. Res. Lett., 36, L07202, doi: 10.1029/2008GL036977.