Abstract Periodic auroral arcs, commonly witnessed by All‐sky imagers, exhibit frequencies consistent with Pc5 band field line resonances (FLRs) in the magnetosphere. Our study specifically reports on a poleward‐moving periodic auroral arc event, observed at the dawn side by the Gilliam station, with a periodicity of 4 min. Ground‐based magnetometers and the GOES13 satellite detected ultralow frequency (ULF) waves with the same 4‐min period. The amplitudes and phase shifts of these ULF waves along latitudes displayed clear FLR characteristics, while variations in ground magnetic field perturbations along longitudes indicated westward‐propagating, localized ULF waves. The FLR regions aligned precisely with the aurora arcs in both latitude and longitude, reinforcing the notion that these localized ULF waves govern the behavior of FLR arcs. The presence of boomerang‐shaped stripes on the ion pitch angle spectrum, recorded by VAP‐B at midnight, provides further evidence for westward‐propagating, localized ULF waves. These findings underscore a robust spatiotemporal correlation between periodic auroral arcs and localized ULF waves, thereby elucidating their intricate relationship.
Zhao et al. (Wed,) studied this question.