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

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.