On the Role of ULF Waves in the Spatial and Temporal Periodicity of Energetic Electron Precipitation
On the Role of ULF Waves in the Spatial and Temporal Periodicity of Energetic Electron Precipitation
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超低频波在高能电子沉淀时空周期性中的作用
DOI：
10.1029/2022ja030932
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Wilkins, Colin
中科院分区：
文献类型：
--
作者：
Shi, Xiaofei;Zhang, Xiao‐Jia;Artemyev, Anton;Angelopoulos, Vassilis;Hartinger, Michael D.;Tsai, Ethan;Wilkins, Colin
高能电子向地球大气的沉淀是控制辐射带动力学和磁层-电离层耦合的关键过程。降水的主要驱动力之一是哨声模波对电子的共振散射。对这种降水的低空观测通常显示出与哨声模波有关的超低频(ULF)范围内的准周期性，这种准周期性与超低频调制的赤道电子通量及其各向异性有关。地面仪器和赤道航天器之间的连接表明，与赤道哨声模波同时存在的低海拔降水在大空间区域上也表现出作为纬度函数的空间周期性。由于赤道航天器、近地轨道航天器和地面仪器之间缺乏联系，这种空间周期性是否也可能是由于磁层超低频波空间调制电子通量和哨声模式合唱的问题以前没有得到解决。为了研究这个问题，我们将地面和赤道观测与低海拔极地轨道CubeSats电子损失和场调查-A和-B的降水观测结合起来，当它们以几分钟到几十分钟的时间间隔顺序穿过外辐射带时，它们可以很容易地揭示电子降水的空间准周期性。我们的组合数据集证实，ULF波可以调制赤道磁层大磁场局部时间和L壳域内哨声模波的产生，从而导致显著的聚集高能电子沉淀，表现出时间和空间周期。我们的结果表明，超低频和哨声模波之间的耦合对于外辐射带的动力学是重要的。
Energetic electron precipitation to the Earth's atmosphere is a key process controlling radiation belt dynamics and magnetosphere‐ionosphere coupling. One of the main drivers of precipitation is electron resonant scattering by whistler‐mode waves. Low‐altitude observations of such precipitation often reveal quasi‐periodicity in the ultra‐low‐frequency (ULF) range associated with whistler‐mode waves, causally linked to ULF‐modulated equatorial electron flux and its anisotropy. Conjunctions between ground‐based instruments and equatorial spacecraft show that low‐altitude precipitation concurrent with equatorial whistler‐mode waves also exhibits a spatial periodicity as a function of latitude over a large spatial region. Whether this spatial periodicity might also be due to magnetospheric ULF waves spatially modulating electron fluxes and whistler‐mode chorus has not been previously addressed due to a lack of conjunctions between equatorial spacecraft, low earth orbit spacecraft, and ground‐based instruments. To examine this question, we combine ground‐based and equatorial observations magnetically conjugate to observations of precipitation at the low‐altitude, polar‐orbiting CubeSats Electron Losses and Fields Investigation‐A and ‐B. As they sequentially cross the outer radiation belt with a temporal separation of minutes to tens of minutes, they can easily reveal the spatial quasi‐periodicity of electron precipitation. Our combined data sets confirm that ULF waves may modulate whistler‐mode wave generation within a large magnetic local time andL‐shell domain in the equatorial magnetosphere, and thus lead to significant aggregate energetic electron precipitation exhibiting both temporal and spatial periodicity. Our results suggest that the coupling between ULF and whistler‐mode waves is important for outer radiation belt dynamics.
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影响因子：
5.2
作者：
Gan, L.;Li, W.;Ma, Q.;Artemyev, A. V.;Albert, J. M.
通讯作者：
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影响因子：
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发表时间：
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期刊：
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影响因子：
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DOI：
10.1016/0021-9169(71)90086-9
发表时间：
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影响因子：
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影响因子：
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作者：
S. Buchert;R. Fujii;K. Glassmeier
通讯作者：
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