Journal of Geophysical Research: Space Physics On the Asymmetry Between Upward and Downward Field-Aligned Currents Interacting With the Ionosphere
Journal of Geophysical Research: Space Physics On the Asymmetry Between Upward and Downward Field-Aligned Currents Interacting With the Ionosphere
复制标题
地球物理研究杂志：空间物理学关于与电离层相互作用的向上和向下场对准电流之间的不对称性
DOI：
10.1029/2020ja027866
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Hui Zhong
中科院分区：
文献类型：
--
作者：
Xiu;Li;Hui Zhong
本文介绍了北半球和南半球磁共轭高纬度地区大尺度电场驱动的磁层-电离层相互作用的数值研究结果。双流体 MHD 模型的模拟表明，这些相互作用可以导致产生小规模、强烈的场对准电流系统，并且向上和向下电流之间的大小和幅度存在显着差异。特别是，在两个半球中，向下的电流（电子从电离层流出的地方）变得比相邻的向上电流更窄、更强烈。在高纬度地区，场对准电流与离散的极光弧密切相关。事实上，这种机制产生嵌入更广泛的向上电流区域的非常狭窄和强烈的向下电流，这使得它与“黑色”极光弧的解释相关，该极光弧表现为嵌入广泛的发光背景中的狭窄、黑暗的条带。描述由 ULF 电磁波和 FAC 在高纬度地区进行的磁层-电离层相互作用的双流体 MHD 模型的模拟结果。本研究的目的是解释具有黑极光特征的 FAC 系统的自洽形成。这项研究的结果表明，黑色极光是由两个共轭半球同时产生的强非线性IFI产生的。黑色极光发展的有利条件包括相对和向下的FAC发展条件与解释黑色极光的观测特征相互作用。
The paper presents results from the numerical study of the magnetosphere-ionosphere interactions driven by the large-scale electric field in the magnetically conjugate, high-latitude regions of northern and southern hemispheres. Simulations of the two-fluid MHD model demonstrate that these interactions can lead to a generation of a system of small-scale, intense field-aligned currents with a significant difference in size and amplitude between the upward and downward currents. In particular, in both hemispheres, the downward currents (where the electrons are flowing from the ionosphere) become more narrow and intense than the adjacent upward currents. At high latitudes, the field-aligned currents are closely related to the discrete auroral arcs. The fact that this mechanism produces very narrow and intense downward currents embedded into the broader upward current regions makes it relevant to the explanation of the “black” auroral arcs appearing as narrow, dark strips embedded in the broad luminous background. results from simulations of a two-fluid MHD model describing magnetosphere-ionosphere interaction conducted by ULF electromagnetic waves and FACs at high latitudes. The goal of this study is to explain self-consistent formation of the FAC system with the characteristic features of the black aurora. Results from this study suggest that the black aurora is produced by the strongly nonlinear IFI developed simultaneously in two conjugate hemispheres. The favorable conditions for the development of the black include relatively and field in should field The conditions development in and downward FAC interacting with the explain observational features of black aurora.