PostDoctoral Research Fellowship

该奖项的目的是：(1)建立一个在两个半球的两极电离层之间流动的半球间场向流（ihc）的数值模型，(2)研究这些电流对两个半球两极地区地磁活动、电离层和高层大气的预期影响，(3)将建模结果与实验数据进行比较。南北高纬度电离层间的ihc流主要是由于两极电离层电导率的差异而存在的。由于地球的方向，在北半球的夏季（南半球的冬季），这些半球间的电流可能非常强，并且在特定的世界时（UT）间隔内，与流入和流出各自半球的总场向电流（FACs）的大小相当。当它们穿过赤道平面时，它们不会改变方向；因此，它们可能会增加一个半球的总FACs强度，而降低另一个半球的总FACs强度。这可能导致整个fas系统的强烈不对称性，以及两极地区特定的地磁和电离层干扰。这项研究将使人们更好地了解fas系统的半球间不对称性、南北极光、电离层扰动和地磁活动的UT变化。所提议的半球间电流模式也将是一套空间天气模式的重要组成部分，改进对两个半球的地磁和电离层扰动及其对低轨道航天器的潜在影响的空间天气预报。

This award is to (1) develop a numerical model of Interhemispherical Field-Aligned Currents (IHCs) flowing between polar ionospheres in two hemispheres, (2) examine expected effects of these currents on geomagnetic activity, ionosphere, and upper atmosphere in the polar regions in both hemispheres, and (3) compare the modeling results with experimental data. The IHCs flow between the Northern and Southern high-latitude ionospheres exists predominantly due to differences in the ionospheric conductivity of the respective polar regions. Due to the Earth's orientation, the northern summer (southern winter) these interhemispherical currents can be very strong and comparable in magnitude with the total field-aligned currents (FACs) flowing in and out of the respective hemispheres at the specific Universal Time (UT) intervals. While crossing an equatorial plane, the IHCs do not change their direction; and as a result, they may increase the total FACs strength in one hemisphere, but decrease it in the opposite hemisphere. This can lead to the strong asymmetry in the total FACs system, as well as to specific geomagnetic and ionospheric disturbances in the two polar regions. The research will bring better understanding of interhemispherical asymmetry in the FACs system, northern and southern auroras, and ionospheric disturbances and UT variations in geomagnetic activity. The proposed model of interhemispherical currents would also be an important component of the set of Space Weather models, improving space weather forecasts of geomagnetic and ionospheric disturbances over two hemispheres and their potential effects on the low-orbiting spacecraft.