Origin of Poleward-Moving Auroral Forms

Most researchers believe poleward-moving Auroral Forms are the ionosphericsignatures of magnetic reconnection on the dayside magnetosphere. Ground-basedoptical instruments have captured auroral forms drifting poleward from the daysideauroral oval. This study looks at the origin of PMAFs before they begin to driftpoleward. The PMAFs in this study begin to brighten on the most visible poleward arcobserved on the dayside auroral oval. These pre-existing auroral arcs initially brightenon the most eastward or westward end. The initial brightening spreads through the pre-existing arc before it begins its poleward journey. Numerous examples are presentedalong with the solar wind conditions, interplanetary magnetic field (IMF) and solar windspeed. Our data was collected by the BACC All-sky camera at the Kjell HenriksenObservatory, located in Longyearbyen, Svalbard.