Pulsating dayside aurora in relation to ion upflow events during a northward interplanetary magnetic field (IMF) dominated by a strongly negative IMF BY

摘要

We report a study of ion upflow as seen by the European Incoherent Scatter (EISCAT) Svalbard Radar (ESR), initiated by a rotation from interplanetary magnetic field (IMF) BZ negative to IMF BZ positive, under the influence of a strongly negative IMF BY. We combine ground-based instruments, such as meridian scanning photometers (MSP), all-sky imager (ASI) data, and radars, with solar wind data from the Advanced Composition Explorer (ACE) spacecraft and low-altitude particle precipitation data from the Defense Meteorological Satellite Program (DMSP) F-13 spacecraft as well as wave data from the Svalbard EISCAT Rocket Study of Ion Outflows (SERSIO) sounding rocket flight. Following a coronal mass ejection, the solar wind data showed high dynamic pressures (up to 20 n Pa) and a strongly varying IMF. The observed ion upflow was seen to be of a pulsed nature and sustained by pulsed soft electron precipitation. The data findings indicated pulsed lobe reconnection as the mechanism funneling energy and momentum down to the northern polar hemisphere.