Unusually elongated, bright airglow plume in the polar cap F region: Is it a tongue of ionization?
Unusually elongated, bright airglow plume in the polar cap F region: Is it a tongue of ionization?
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DOI：
10.1029/2009gl037512
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发表时间：
2009-04
影响因子：
5.2
通讯作者：
K. Hosokawa;T. Tsugawa;K. Shiokawa;Y. Otsuka;T. Ogawa;M. Hairston
中科院分区：
文献类型：
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作者：
K. Hosokawa;T. Tsugawa;K. Shiokawa;Y. Otsuka;T. Ogawa;M. Hairston
我们报告了一个异常细长的明亮的气辉羽流事件，这被认为是中央极冠电离舌（TOI）的光学表现。这个光学结构是在2006年12月15日的一场大磁暴期间，在Resolute Bay（74.73°N，265.07°E）用全天空气辉成像仪探测到的。烟羽的绝对光学强度为1.01 kR，比非风暴时的极冠斑块亮得多。全天空成像仪的二维成像能力表明，一些中尺度结构（250-600公里）嵌入在羽流中。DMSP航天器的同时离子密度和漂移测量强烈表明，羽流从日照面延伸为狭窄的致密等离子体流，因此是极帽TOI的光学表现。DMSP数据还表明，烟羽的可能来源是从低纬度地区输送来的风暴增强密度（SED）的狭窄气流。DMSP极光粒子观测表明，在此期间，极帽向赤道方向极度扩张。这种极端的膨胀使得反向阳对流能够捕获SED内的等离子体，并将它们作为发光的气辉羽流输送到极冠深处。这一观测结果表明，磁暴期间来自向阳面低纬的等离子体输运对控制极帽电离层等离子体环境起着重要作用。
We report an event of unusually elongated, bright airglow plume, which is considered as an optical manifestation of tongue of ionization (TOI) in the central polar cap. This optical structure was detected with an all‐sky airglow imager at Resolute Bay (74.73°N, 265.07°E) during a large magnetic storm on December 15, 2006. The absolute optical intensity of the plume was ≈1 kR, which is much brighter than that of non‐stormtime polar cap patches. Two‐dimensional imaging capability of the all‐sky imager demonstrates that some meso‐scale structures (≈250–600 km) were embedded within the plume. Simultaneous ion density and drift measurements with the DMSP spacecraft strongly suggest that the plume was extending from the dayside as a narrow stream of dense plasma and thus is an optical manifestation of polar cap TOI. The DMSP data also implies that the possible source of the plume is a narrow stream of storm enhanced density (SED) transported from lower latitudes. The DMSP auroral particle observation demonstrates that the polar cap extremely expanded equatorward during this interval. This extreme expansion allowed the anti‐sunward convection to capture plasmas within the SED and deliver them deep into the polar cap as a luminous airglow plume. This observation claims that the plasma transport from the dayside lower latitudes plays an important role in controlling the plasma environment in the polar cap ionosphere during magnetic storms.