A Survey of Dense Low Energy Ions in Earth's Outer Magnetosphere: Relation to Solar Wind Dynamic Pressure, IMF, and Magnetospheric Activity.
A Survey of Dense Low Energy Ions in Earth's Outer Magnetosphere: Relation to Solar Wind Dynamic Pressure, IMF, and Magnetospheric Activity.
复制标题
对地球外磁层中致密的低能离子的调查：与太阳风动压力，IMF和磁层活性的关系。
DOI：
10.1029/2021ja029208
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发表时间：
2021-09
影响因子：
2.8
通讯作者：
Angelopoulos, Vassilis
中科院分区：
文献类型：
--
作者：
Hull, Arthur J.;Agapitov, Oleksiy;Mozer, Forrest S.;McFadden, James P.;Angelopoulos, Vassilis
关键词：
在2016年6月至2017年7月运行的新的低能等离子体模式期间，使用亚暴航天器期间的事件时间历史和大尺度相互作用采样的数据，检查了地球磁层内6至14距离之间的冷，密集，低能（150 eV）离子的特性。在太阳风动压和/或磁层活动增强期间，这些离子是磁层的一个持久特征。这些离子的密度范围从0.5到几十，平均值为1，温度为几到几十eV，平均值为13 eV。这些产生的冷热离子密度和温度比分别为4.4和4.5。比较结果表明，冷离子密度与太阳风动压呈正相关。根据它们的俯仰角分布，这些离子是可组织的，作为横向/对流主导（解释为羽流等离子体）或磁场对齐（FAL）（离子流出或斗篷等离子体的单向或双向特性）。横向离子优先发生在午前至黄昏部门在持续活跃的磁层条件下，由增强的太阳风动力压力驱动下向南和向西IMF的方向。横向离子速度（达到几十公里/秒）有一个向西的趋势，轻微的径向向外的偏好。相反，FAL离子优先发生从早上到中午在朝北的IMF方向，增强太阳风动压，安静的磁层条件下，在几个小时内，中等到强的活动。FAL离子也具有30 km/s的体速度，具有向东和径向向外的趋势。在太阳风动压和/或Kp增强期间，密集的低能离子是磁层的一个持久特征。低能横向离子倾向于在向南B z和向西B y IMF条件下出现在黄昏侧磁层，并有向西流动。低能磁场对准（单向或双向）离子倾向于在向北IMF条件下出现在黎明侧，并有向东流动。
The properties of cold, dense, low energy (150 eV) ions within Earth's magnetosphere between 6 and 14 distance are examined using data sampled by Time History of Events and Macroscale Interactions during Substorms spacecraft during a new low‐energy plasma mode that operated from June 2016 to July 2017. These ions are a persistent feature of the magnetosphere during enhanced solar wind dynamic pressure and/or magnetospheric activity. These ions have densities ranging from 0.5 to tens of , with a mean of 1 and temperatures of a few to tens of eV, with a mean of 13 eV. These yield cold to hot ion density and temperature ratios that are 4.4 and , respectively. Comparisons reveal that the cold ion densities are positively correlated with solar wind dynamic pressure. These ions are organizable, according to their pitch‐angle distribution, as being transverse/convection dominated (interpreted as plume plasma) or magnetic field‐aligned (FAL) (uni‐ or bi‐directional characteristic of ion outflow or cloak plasma). Transverse ions preferentially occur in the prenoon to dusk sectors during sustained active magnetospheric conditions driven by enhanced solar wind dynamic pressure under southward and westward IMF orientations. Transverse ion velocities (reaching several tens of km/s) have a westward directed tendency with a slight radially outward preference. In contrast FAL ions preferentially occur from morning to noon during northward IMF orientations, enhanced solar wind dynamic pressure, and quiet magnetospheric conditions within several hours after moderate to strong activity. The FAL ions also have bulk velocities 30 km/s, with an eastward and radially outward tendency. Dense low energy ions are a persistent feature of the magnetosphere during enhanced solar wind dynamic pressure and/or Kp Low energy transverse ions tend to occur in duskside magnetosphere under southward B z and westward B y IMF conditions, with westward flow Low energy magnetic field‐aligned (uni‐ or bi‐directional) ions tend to occur in the dawnside under northward IMF, with an eastward flow