Multiscale magnetosphere-ionosphere coupling during stormtime: A case study of the dawnside current wedge

We further show that these periods are characterized by the penetration of mesoscale bursty bulk flows (BBFs) into the dawnside inner magnetosphere. In the context of this event we find that the development of the asymmetric ring current, which inflates the dusk-side magnetotail, leads to asymmetric reconnection and dawnward-biased flow bursts. This results in an eastward expansion and multiscale enhancement of the dawnside electrojet.

The electrojet enhancement extends across the dawn quadrant with localized enhancements associated with the wedgelet current systems of the penetrating BBFs. Finally, we connect this work with recent studies that have shown rapid, localized ground variability on the dawnside which can lead to hazardous geomagnetically induced currents.