Leveraging Commercial Cubesat Constellations for Auroral Science: A Case Study
Leveraging Commercial Cubesat Constellations for Auroral Science: A Case Study
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利用商业立方卫星星座进行极光科学：案例研究
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
J. Semeter
中科院分区：
文献类型：
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作者：
J. Parham;Vincent Beukelaers;Lawrence Leung;J. Mason;B. Walsh;J. Semeter
部署在迄今为止最大的卫星星座上的磁强计被用作天基传感器网络，以研究极光场向电流（FACs）的时空变化。行星实验室公司的立方体卫星星座。由近200颗卫星组成，分布在两个极地太阳同步轨道上，航天器间距中位数约为375公里，有时有机会提供更近的间距。每个航天器都包含一个磁感应磁力计，能够以0.1至10 Hz的频率对环境磁场进行采样，灵敏度<200-nT。在这项研究中，来自行星星座的七颗卫星被用来研究在10分钟间隔内活跃的极光显示期间FACs的时空变化。极光发生在地磁风暴的早期恢复阶段，其特征是大规模的涡旋运动和嵌入式射线结构。轨道磁力计探测到了大规模极光系统的清晰特征。使用三种不同的方法进行FAC模式的估计。结果表明，在10分钟间隔内存在高度的空间和时间变异性。相对于极光的向上和向下电流通道的位置与理论预期一致，但电流密度与可用图像中的可见特征没有很好的相关性，这表明合作观测没有捕获到未解决的小尺度结构。讨论了使用低质量空间磁力计的机会网络来研究动态极光现象的优点，局限性和警告。
Magnetometers deployed on the largest satellite constellation to date are leveraged as a space‐based sensor network to study space‐time variability in auroral field‐aligned currents (FACs). The cubesat constellation of Planet Labs Inc. consists of nearly 200 satellites in two polar Sun‐synchronous orbits, with median spacecraft separations on the order of 375 km, and some occasions of opportunity providing much closer spacing. Each spacecraft contains a magnetoinductive magnetometer, able to sample the ambient magnetic field at 0.1 to 10 Hz with <200‐nT sensitivity. In this study, seven satellites from the Planet constellation were used to investigate space‐time variations in FACs over an active auroral display during a 10‐min interval. The aurora occurred during the early recovery phase of a geomagnetic storm and was characterized by large‐scale vortical motions and embedded rayed structure. Clear signatures of the large‐scale auroral current system were detected by the orbital magnetometers. Estimation of FAC patterns was carried out using three different methods. The results suggest a high degree of spatial and temporal variability during the 10‐min interval. The location of upward and downward current channels relative to the aurora was consistent with theoretical expectations, but current densities were not well correlated with visible features in the available imagery, suggesting unresolved small‐scale structure not captured by the collaborative observations. Advantages, limitations, and caveats in using opportunistic networks of low‐quality space‐based magnetometers to study dynamic auroral phenomena are discussed.