Small-scale dynamic auroras have spatial scales of a few km or less, and temporal scales of a few seconds or less, which visualize the complex interplay among charged particles, Alfvén waves, and plasma instabilities working in the magnetosphere-ionosphere coupled regions. We summarize the observed properties of flickering auroras, vortex motions, and filamentary structures. We also summarize the development of fundamental theories, such as dispersive Alfvén waves (DAWs), plasma instabilities in the auroral acceleration region, ionospheric feedback instabilities (IFI), and the ionospheric Alfvén resonator (IAR).

中文翻译：

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小尺度动态极光

小尺度动态极光的空间尺度为几公里或更小，时间尺度为几秒或更短，它们可视化了在磁层-电离层耦合区域中工作的带电粒子、阿尔芬波和等离子体不稳定性之间的复杂相互作用。我们总结了观测到的闪烁极光、涡旋运动和丝状结构的特性。我们还总结了基本理论的发展，例如色散阿尔文波 (DAW)、极光加速区域中的等离子体不稳定性、电离层反馈不稳定性 (IFI) 和电离层阿尔文谐振器 (IAR)。