Fuselier S A, Dayeh M A, Galli A, Funsten H O, Schwadron N A, Petrinec S M, Trattner K J, McComas D J, Burch J L, Toledo-Redondo S, Szalay J R, Strangeway R J
Southwest Research Institute San Antonio TX USA.
Department of Physics and Astronomy University of Texas at San Antonio San Antonio TX USA.
Geophys Res Lett. 2020 Oct 16;47(19):e2020GL089362. doi: 10.1029/2020GL089362. Epub 2020 Oct 5.
Energetic neutral atoms (ENAs) created by charge-exchange of ions with the Earth's hydrogen exosphere near the subsolar magnetopause yield information on the distribution of plasma in the outer magnetosphere and magnetosheath. ENA observations from the Interstellar Boundary Explorer (IBEX) are used to image magnetosheath plasma and, for the first time, low-energy magnetospheric plasma near the magnetopause. These images show that magnetosheath plasma is distributed fairly evenly near the subsolar magnetopause; however, low-energy magnetospheric plasma is not distributed evenly in the outer magnetosphere. Simultaneous images and in situ observations from the Magnetospheric Multiscale (MMS) spacecraft from November 2015 (during the solar cycle declining phase) are used to derive the exospheric density. The ~11-17 cm density at 10 R is similar to that obtained previously for solar minimum. Thus, these combined results indicate that the exospheric density 10 R from the Earth may have a weak dependence on solar cycle.
在日下点磁层顶附近，离子与地球氢外层大气发生电荷交换所产生的高能中性原子（ENA），能提供关于外磁层和磁鞘层中等离子体分布的信息。星际边界探测器（IBEX）的ENA观测结果被用于绘制磁鞘层等离子体图像，并且首次绘制了磁层顶附近的低能磁层等离子体图像。这些图像显示，在日下点磁层顶附近，磁鞘层等离子体分布相当均匀；然而，低能磁层等离子体在外磁层中的分布并不均匀。利用磁层多尺度（MMS）航天器在2015年11月（太阳活动周期下降阶段）的同步图像和原位观测数据来推导外层大气密度。在10个地球半径处约11 - 17厘米的密度与之前太阳活动极小期所获得的密度相似。因此，这些综合结果表明，距离地球10个地球半径处的外层大气密度可能对太阳活动周期的依赖性较弱。
