Mesoscales, which couple small to large scales, and vice-versa, are critical to the magnetosphere-ionosphere coupling. Optical and radar measurements indicate that dynamical mesoscale features are present in the ionosphere, however quantifying their contribution to the overall dynamics remains a challenge. We use a new ionospheric data assimilation technique, Lompe (Local mapping of the polar ionospheric electrodynamics), to specify ionospheric electrodynamics using a wide variety of input data and a priori assumptions about the physical nature of the ionospheric electric field. We isolate the terms of the ionospheric Ohm's law and find that mesoscale structures in the FACs are driven by Hall gradients, while the larger scale patterns are associated with the divergence of the electric field. We calculate the relative contribution of mesoscales to the overall FAC patterns during a magnetospheric substorm, and find that in the nightside, mesoscale FACs contribute up to 60% of the total.

中文翻译：

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量化磁层子风暴期间中尺度对 FAC 的贡献


介尺度耦合小尺度到大尺度，反之亦然，对于磁层-电离层耦合至关重要。光学和雷达测量表明，电离层中存在动力学中尺度特征，但量化它们对整体动力学的贡献仍然是一个挑战。我们使用一种新的电离层数据同化技术 Lompe（极地电离层电动力学的局部映射），使用各种输入数据和关于电离层电场物理性质的先验假设来指定电离层电动力学。我们分离出电离层欧姆定律的项，发现 FAC 中的中尺度结构由霍尔梯度驱动，而更大尺度的模式与电场的发散有关。我们计算了磁层亚风暴期间中尺度对整体 FAC 模式的相对贡献，发现在夜间，中尺度 FAC 贡献高达 60%。