Ionospheric and Solar Wind Contributions to the Storm-Time Near-Earth Plasma Sheet
Ionospheric and Solar Wind Contributions to the Storm-Time Near-Earth Plasma Sheet
复制标题
DOI：
10.1029/2020gl090235
复制
发表时间：
2020-11-28
影响因子：
5.2
通讯作者：
Kistler, L. M.
中科院分区：
文献类型：
--
作者：
Kistler, L. M.
风暴时环电流是由近地等离子体片向内对流形成的，因此了解等离子体片的变化来源是理解环电流发展的关键。通过重离子的带电状态可以区分电离层源和太阳风源；太阳风离子高度电离，而电离层离子主要是单电离。AMPTE/CHEM测量用于跟踪风暴发展过程中6-9 Re等离子体片成分的变化，以确定来自每种来源的人口比例。我们发现，在风暴之前，太阳风源占主导地位。在风暴主阶段，太阳风的贡献减小，电离层的贡献增大，使源以电离层为主。在恢复阶段，辐射源以太阳风等离子体为主。被困在地球磁场中的离子有两个可能的来源：太阳或地球的电离层。来自太阳的一股被称为太阳风的电离粒子流不断地向外移动，流经地球。这些粒子可以进入地球的磁层并被困住。离子也可以加速离开电离层进入磁层。这两种来源之间的相互作用尚不清楚。在本文中，我们测试了一个大的地磁风暴的源如何变化。我们发现，在风暴高峰期，来源从主要是太阳风转变为主要是电离层。利用AMPTE/CHEM仪器跟踪了一次风暴期间近地等离子体层的电离层源和太阳风源，在风暴主阶段的两次增强期间，源都从以太阳风为主转变为电离层源，在恢复阶段，源又以太阳风为主转变
The storm-time ring current is formed by the inward convection of the near-earth plasma sheet, so understanding the changing source of the plasma sheet is key for understanding ring current development. The ionospheric and solar wind sources can be distinguished by the charge state of the heavy ions; solar wind ions are highly iononized, while ionospheric ions are predominantly singly ionized. AMPTE/CHEM measurements are used to track the changing composition in the 6-9 Re plasma sheet as a storm develops in order to determine the fraction of the population that comes from each source. We find that prior to the storm, the solar wind source dominates. During the storm main phase, the solar wind contribution decreases, while the ionospheric contribution increases, making the source predominantly ionospheric. The source returns to predominantly solar wind plasma during the recovery phase.Plain Language Summary The ions trapped in the earth's magnetic field have two possible sources: the sun or the earth's ionosphere. A stream of ionized particles from the sun called the solar wind is constantly moving outward, flowing by the earth. These particles can enter the earth's magnetosphere and become trapped. Ions can also be accelerated out of the ionosphere into the magnetosphere. The interplay between these two sources is not well understood. In this paper, we test how the source changes as a large geomagnetic storm develops. We find that the source switches from being dominantly solar wind, to dominantly ionospheric during the peak of the storm.Key PointsIonospheric and solar wind sources to the near-earth plasma sheet are tracked during one storm using the AMPTE/CHEM instrument There is a sharp change from a predominantly solar wind to ionospheric source during both intensifications in the storm's main phase The source changes back to predominantly solar wind during the recovery phase