We examined how much large-scale and localized upward and downward currents contribute to the substorm current wedge (SCW), and how they evolve over time, using the THEMIS all-sky imagers (ASIs) and ground magnetometers. One type of events is dominated by a single large-scale wedge, with upward currents over the surge and broad downward currents poleward-eastward of the surge. The other type of events is a composite of large-scale wedge and wedgelets associated with streamers, with each wedgelet having comparable intensity to the large-scale wedge currents. Among 17 auroral substorms with wide ASI coverage, the composite current type is more frequent than the single large-scale wedge type. The dawn–dusk size of each wedgelet is ~ 600 km in the ionosphere (~ 3.2 R E in the magnetotail, comparable to the flow channel size). We suggest that substorms have more than one type of SCW, and the composite current type is more frequent.

中文翻译：

---

大尺度和楔形电流在亚暴电流楔中的相对贡献

我们使用 THEMIS 全天成像仪 (ASI) 和地面磁力计检查了大规模和局部向上和向下电流对亚暴电流楔 (SCW) 的贡献程度，以及它们如何随时间演变。一种类型的事件由一个单一的大型楔形主导，在浪涌上有向上的电流，而在浪涌的极地向东有广泛的向下电流。另一种类型的事件是与拖缆相关的大型楔形和楔形波的组合，每个楔形波的强度与大型楔形电流相当。在ASI覆盖范围广的17个极光亚暴中，复合流型比单一的大尺度楔型更频繁。电离层中每个楔形波的黎明-黄昏大小约为 600 公里（磁尾中约为 3.2 RE，与流道大小相当）。