资源环境科技发展态势分析平台

Advances in networks of ground-based optical instrumentation have enabled us to identify over 400 examples of auroral arcs with an infrequently observed, temporally periodic auroral morphology. This study focuses on these arcs observed via the 630-nm ("redline") auroral emission wavelength and connects them to global magnetospheric wave modes known as field line resonances (FLRs). We show that optical redline FLR auroral arcs occur most frequently near 20 and 4 magnetic local time, in contrast to nonperiodic redline arcs, which occur most frequently near midnight. We find that this periodic type of auroral arc is rare, occurring in approximately 5% of redline aurora observed by the Redline Emission Geospace Observatory all-sky imagers. We also show Swarm satellite observations of two separate instances of 630-nm FLR arcs with strong upward field-aligned currents of the order of 3-6 mu A/m(2).