We investigate electric current structures in Short Large-Amplitude Magnetic Structures (SLAMS) in the terrestrial ion foreshock region observed by the Magnetospheric Multiscale mission. The structures with intense currents (|J|~1 {\mu}A/m^2) have scale lengths comparable to the local ion inertial length (di). One current structure type is a current sheet due to the magnetic field rotation of the SLAMS, and a subset of these current sheets can exhibit reconnection features including the electron outflow jet and X-line-type magnetic topology. The di-scale current sheet near the edge of a SLAMS propagates much more slowly than the overall SLAMS, suggesting that it may result from compression. The current structures also exist as magnetosonic whistler waves with fci < f < flh, where fci and flh are the ion cyclotron frequency and the lower-hybrid frequency, respectively. The field rotations in the current sheets and whistler waves generate comparable |J| and energy conversion rates. Electron heating is clearly observed in one whistler packet embedded in a larger-scale current sheet of the SLAMS, where the parallel electric field and the curvature drift opposite to the electric field energize electrons. The results give insight about the thin current structure generation and energy conversion at thin current structures in the shock transition region.

中文翻译：

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短大振幅磁结构中的离子尺度电流结构

我们研究了磁层多尺度任务观测到的地球离子前震区域中短大振幅磁结构 (SLAMS) 中的电流结构。具有强电流 (|J|~1 {\mu}A/m^2) 的结构具有与局部离子惯性长度 (di) 相当的尺度长度。由于 SLAMS 的磁场旋转，一种电流结构类型是电流片，这些电流片的一个子集可以表现出重连接特征，包括电子流出射流和 X 线型磁拓扑。SLAMS 边缘附近的双尺度电流片比整个 SLAMS 传播得慢得多，这表明它可能是由压缩引起的。电流结构也以 fci < f < flh 的磁声哨声波形式存在，其中 fci 和 flh 分别是离子回旋频率和低混合频率。电流片和惠斯勒波中的场旋转产生类似的|J| 和能量转换率。在嵌入 SLAMS 的更大规模电流片中的一个whisler 包中清楚地观察到电子加热，其中平行电场和与电场相反的曲率漂移为电子提供能量。结果提供了有关激波过渡区薄电流结构的薄电流结构生成和能量转换的见解。其中平行电场和与电场相反的曲率漂移为电子提供能量。结果提供了有关激波过渡区薄电流结构的薄电流结构生成和能量转换的见解。其中平行电场和与电场相反的曲率漂移为电子提供能量。结果提供了有关激波过渡区薄电流结构的薄电流结构生成和能量转换的见解。