A statistical study of the motion of pulsating aurora patches: using the THEMIS All-Sky Imager

Abstract. Previous studies of the motion of patches that comprise patchy pulsating aurora (PPA) have been based on a limited number of events. In this study, we use a large database of PPA patches obtained from the THEMIS all-sky imager at Gillam (66.18° magnetic latitude, 332.78° magnetic longitude) between May 2006 and July 2013 to explore the velocity of the PPA patches. Our results show that PPA patches mainly drift eastward after midnight and westward before midnight. In addition, we found that patch velocities are in the expected range of convection given the magnetic latitude and that the velocities do not seem to depend on auroral electrojet (AE) index. The results suggest that the drifts of auroral patches could be a proxy for the ionospheric convection, and possibly provide a convenient and accurate method to remotely sense the magnetospheric convection.