Ionospheric Evidence of Lobe Reconnection for Northward IMF

It is believed that magnetic reconnection is one of the main mechanisms to transfer energy and momentum from the for the solar wind into the terrestrial environment. Dungey suggested that magnetic reconnection occurs on the dayside magnetosphere when the interplanetary magnetic field (IMF) is southward. Poleward moving auroral forms (PMAFs) have been identified in past studies as Ionospheric signatures of magnetic reconnection on the dayside. However, magnetic reconnection can also occur for other geometrical orientations of the IMF. This presentation presents possible examples, 1 December 2021, for lobe reconnection during periods when the IMF x-component is negative, coupled with a positive IMF y-component and IMF z-component. Auroral forms are observed to brighten and move equatorward instead of poleward during this IMF configuration between 16-17 UT and they coincide with sharp deflections in the ground magnetometer X-component. Ground-based data is obtained from the Kjell Henriksen Observatory (all-sky camera and meridian scanning photometer) in Longyearbyen and the IMAGE magnetometer network.