Contribution of dayside transients to the reconnection voltage

Abstract:

There are a range of different dayside transient signatures relating to the coupling between the solar wind and the terrestrial magnetosphere. Flux transfer events are one particular example of dayside transients which play a key role in the transport of energy and momentum through the process of magnetic reconnection. FTEs are widely observed at the dayside magnetopause while also having signatures in the ionosphere, through such events as poleward moving auroral forms or poleward moving radar auroral forms. Here we consider the link between the convection generated by FTEs and the poleward moving radar auroral form to estimate the reconnection voltage and the size of the reconnection line. We will focus on events observed with the Super Dual Auroral Radar Network (SuperDARN) where we can measure the ionospheric convection over a range of local times. These observations need to be placed in the context of the boundary between the open and closed magnetic flux since we need to calculate the convection across that boundary in the frame of the boundary motion to get the reconnection voltage. We place the observations in the framework of the expanding/contracting polar cap model.