On the Role of Last Closed Drift Shell Dynamics in Driving Fast Losses and Van Allen Radiation Belt Extinction
On the Role of Last Closed Drift Shell Dynamics in Driving Fast Losses and Van Allen Radiation Belt Extinction
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最后闭合漂移壳动力学在驱动快速损失和范艾伦辐射带灭绝中的作用
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
D. Choi
中科院分区：
文献类型：
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作者：
L. Olifer;Ian Mann;Steven K. Morley;L. Ozeke;D. Choi
我们目前的观测非常快的辐射带损失解决使用高时间分辨率的电子通量数据从全球定位系统（GPS）卫星星座。这些损失的时间尺度被揭示为短至0.5-2小时，在强烈的磁暴，与一些风暴表现出几乎完全的损失，这些时间尺度上，我们的特征是辐射带灭绝。2013年3月和2015年3月的强烈风暴都显示了如此快速的灭绝，并迅速恢复，而2014年9月的风暴显示了快速灭绝，但大约两周没有恢复。相比之下，2012年9月的中等风暴产生了三个辐射带形态，显示出更渐进的损失。我们计算这四个风暴中的每一个的最后一个封闭的漂移壳层（LCDS），并显示出非常强的对应关系LCDS和被困电子在每个风暴的损失模式。最重要的是，LCDS的位置密切反映了GPS通量中观察到的高时间分辨率损失。快速损失发生在一个时间尺度短于货车艾伦探针轨道周期，解释接近LCDS，并向内进展，与外向运输的LCDS由快速超低频波径向扩散。用L* 表示LCDS的位置，而不是用RE为单位的模型磁层顶距离，清楚地揭示了磁层顶阴影是GPS卫星观测到的快速损失的原因。
We present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ∼0.5–2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, the moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. We compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDS by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.
回复“重新审视范艾伦皮带的动态”
影响因子：
19.6
作者：
Mann I
通讯作者：
Mann I