Magnetospheric imaging via ground-based optical instruments

This chapter introduces a new technique for analyzing all-sky camera (ASC) data. Dayside ASC data are modified using this technique. Dayside auroral observations are important because they are one of the ionospheric signatures of the interactions between the solar wind and the dayside magnetopause. The new technique enhances the edges of the auroral arcs, enabling better visualization of arc locations and brightening events that are not easily observed using the ASC data. This allows for a deeper understanding of the coupling mechanisms between the solar wind and the magnetopause. As an example, this technique is used to analyze events on December 18, 2017. The dayside auroral oval is expanded and several poleward-moving auroral forms (PMAFs) are observed. Using the enhanced auroral images, a preexisting auroral arc is clearly observed at the poleward edge of the dayside auroral oval. This same arc is not readily seen in the ASC data. This preexisting auroral arc begins to drift poleward, giving rise to a PMAF event.