South Pole Station Ground‐Based and Cluster Satellite Measurements of Leaked and Escaping Auroral Kilometric Radiation
South Pole Station Ground‐Based and Cluster Satellite Measurements of Leaked and Escaping Auroral Kilometric Radiation
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南极站地面和集群卫星对泄漏和逃逸极光千米辐射的测量
DOI：
10.1029/2021ja029399
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Pickett, Jolene S.
中科院分区：
文献类型：
--
作者：
LaBelle, James;Yearby, Keith;Pickett, Jolene S.
先前的研究表明，极光千米辐射（AKR）会泄漏到低海拔地区。为了研究这一现象，在2018-2020年的35个间隔期间，在南极、南极洲和星群卫星上同时进行了宽带波测量。在南极观测到泄漏AKR的时间约为5%，在星群卫星上观测到逃逸AKR的时间约为31%。两种类型的AKR都是由精细结构组成的，并且在AKR的不同位置经常同时观察到类似的精细结构。在2020年6月29日0317 UT左右，同时观察到相同的特征。簇干涉测量表明，在此事件中，源场线的足迹位于南极数百公里范围内。在此事件中，在星系团观测到的逃逸AKR的估计发射功率超过了在南极观测到的泄漏AKR的许多数量级，这表明产生泄漏AKR所涉及的模式转换相对低效。两个地点相同的AKR精细结构包括南极接收器工作时在Cluster观测到的AKR的0.1%-0.3%，以及至少一颗Cluster卫星调谐到适当频率范围时在南极观测到的AKR的2%。一致精细结构相对较低的发生率可能部分归因于几何和光束的考虑，但也表明，在地面可探测水平上产生泄漏AKR的过程比在遥远航天器可探测水平上产生逃逸AKR的过程的概率要低。
Previous work suggests that Auroral Kilometric Radiation (AKR) leaks to low altitudes. To investigate this phenomenon, wideband wave measurements have been conducted simultaneously at South Pole, Antarctica, and at the Cluster satellites, during 35 intervals in 2018–2020. Leaked AKR is observed ∼5% of the time at South Pole and escaping AKR ∼31% of the time at Cluster satellites. Both types of AKR are composed of fine structure, and similar fine structure is often observed simultaneously in the AKR at the different locations. Around 0317 UT on 29 June 2020, identical features were observed simultaneously. Cluster interferometry shows that the footprint of the source field line during this event lies within a few hundred kilometers of South Pole. The estimated emitted power of the escaping AKR observed at Cluster in this event exceeds that of the leaked AKR observed at South Pole by many orders of magnitude, suggesting that mode conversion involved in generating leaked AKR is relatively inefficient. AKR fine structure which is identical at the two locations comprises ∼0.1%–0.3% of AKR observed at Cluster when the South Pole receiver operates, and ∼2% of AKR observed at South Pole when at least one Cluster satellite is tuned to the appropriate frequency range. The relatively low occurrence rates of coincident fine structure may be attributed partly to geometric and beaming considerations but also suggest that processes involved in generating leaked AKR at levels detectable at ground level have lower probability than those generating escaping AKR at levels detectable by distant spacecraft.
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DOI：
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发表时间：
2021
期刊：
影响因子：
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作者：
LaBelle;James ; Yearby;Keith ; Pickett;Jolene ; Kojima;H
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1991
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1998
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1997
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