On the origin of low‐energy electrons in the inner magnetosphere: Fluxes and pitch‐angle distributions
On the origin of low‐energy electrons in the inner magnetosphere: Fluxes and pitch‐angle distributions
复制标题
内磁层低能电子的起源：通量和俯仰角分布
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
L. Sarno‐Smith
中科院分区：
文献类型：
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作者：
M. Denton;G. Reeves;B. Larsen;R. Friedel;M. Thomsen;P. Fernandes;R. Skoug;H. Funsten;L. Sarno‐Smith
内磁层等离子体通量的准确知识是必不可少的科学和规划应用。了解内磁层中的低能电子（大约几十到几百eV）是特别重要的，因为这些电子受到各种物理过程的作用，加速电子到更高的能量，也导致它们的损失。然而，低能电子的测量是具有挑战性的，因此，这个群体以前被忽视了。这项研究涉及由货车艾伦探测器卫星上的氦氧质子电子仪器进行的低能电子观测，以及由洛斯阿拉莫斯国家实验室卫星上的磁层等离子体分析仪进行的地球同步轨道观测。从~30 eV到1 keV的电子通量被量化为俯仰角、McIlumeL参数和安静和活跃时期的本地时间的函数。结果表明，在这个能量范围内，低能电子有两个来源：电子等离子体片的低能尾部和向阳面电离层的高能尾部。这些群体主要是由于其不同的俯仰角分布而被识别的。在安静和活跃期间，在所有L壳层观察到来自昼侧电离层的场向外流。我们的研究结果还表明，在约30 eV处的向阳面电子场对准通量在L值为6和7之间特别强，表明极地电离层内的增强源。
Accurate knowledge of the plasma fluxes in the inner magnetosphere is essential for both scientific and programmatic applications. Knowledge of the low‐energy electrons (approximately tens to hundreds of eV) in the inner magnetosphere is particularly important since these electrons are acted upon by various physical processes, accelerating the electrons to higher energies, and also causing their loss. However, measurements of low‐energy electrons are challenging, and as a result, this population has been somewhat neglected previously. This study concerns observations of low‐energy electrons made by the Helium Oxygen Proton Electron instrument on board the Van Allen Probes satellites and also observations from geosynchronous orbit made by the Magnetospheric Plasma Analyzer on board Los Alamos National Laboratory satellites. The fluxes of electrons from ~30 eV to 1 keV are quantified as a function of pitch‐angle, McIlwain L parameter, and local time for both quiet and active periods. Results indicate two sources for low‐energy electrons in this energy range: the low‐energy tail of the electron plasma sheet and the high‐energy tail of the dayside ionosphere. These populations are identified primarily as a result of their different pitch‐angle distributions. Field‐aligned outflows from the dayside ionosphere are observed at all L shells during quiet and active periods. Our results also demonstrate that the dayside electron field‐aligned fluxes at ~30 eV are particularly strong between L values of 6 and 7, indicating an enhanced source within the polar ionosphere.
影响因子：
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作者：
M. Denton;J. Borovsky
通讯作者：
M. Denton;J. Borovsky
地球同步轨道等离子体层磁通管充填观测与模拟
DOI：
10.1002/2014ja020491
发表时间：
2014
期刊：
Space Physics
影响因子：
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作者：
Denton M
通讯作者：
Denton M