This article describes the relationship between shear Alfvén waves and auroral electron acceleration, with an emphasis on long-period standing waves that correlate with redline auroral arcs in the Earth’s magnetosphere. Discrete auroral arcs were correlated with high-latitude field line resonances in the early 1990’s. The past decade has seen advances in all-sky camera technology improve the detection and categorization of “FLR arcs” and establish them as a distinct population. We review observations of redline arcs and discuss estimates of wave amplitudes, wavelengths perpendicular to the geomagnetic field, and saturation times obtained within the framework of two-fluid theories. The two-fluid theory explains the spatial and temporal evolution of FLR optical signatures, but the estimated parallel electric field strengths are insufficient to accelerate electrons and produce 6300 Å auroral emissions. A kinetic theory of FLRs is necessary since electron bounce motion in long-wavelength standing waves affects the ac conductivity and hence the strength of parallel electric fields. In the kinetic theory, the current-voltage relation comprises a conductivity kernel that is a function of the wave frequency, field line length, electron thermal speed, and the number of electron trajectories nearly parallel to geomagnetic field lines close to the ionosphere. The ensuing nonlocal relationship between wave parallel currents and parallel electric fields provides a feasible explanation of the correlation between long-period field line resonances and redline arcs in the terrestrial magnetosphere. The mirror force and particle trapping in the wave fields of shear Alfvén waves are demonstrated to be important aspects of the kinetics of FLRs.

本文描述了剪切阿尔文波与极光电子加速之间的关系，重点介绍了与地球磁层中红线极光弧相关的长周期驻波。在 1990 年代初期，离散的极光弧与高纬度场线共振相关。在过去的十年中，全天空摄像机技术的进步改进了“FLR 弧”的检测和分类，并将它们确立为一个独特的群体。我们回顾了红线弧的观察结果，并讨论了在双流体理论框架内获得的波幅、垂直于地磁场的波长和饱和时间的估计。双流体理论解释了 FLR 光学特征的空间和时间演变，但估计的平行电场强度不足以加速电子并产生 6300 Å 的极光发射。FLR 的动力学理论是必要的，因为长波长驻波中的电子反弹运动会影响交流电导率，从而影响平行电场的强度。在动力学理论中，电流-电压关系包含一个电导率内核，该内核是波频率、场线长度、电子热速度以及与靠近电离层的地磁场线几乎平行的电子轨迹数量的函数。随后波平行电流和平行电场之间的非局域关系为地球磁层中长周期场线共振和红线弧之间的相关性提供了可行的解释。