(50% Seminar) Transpolar auroral arcs and Dayside aurora

The occasional appearance of auroral arcs far poleward of the latitudes where the aurora usually occurs, gives us a hint on the complicated solar wind – magnetosphere – ionosphere coupling processes during quiet geomagnetic times. The textbook picture of the polar cap as a region void of aurora and being directly coupled to the solar wind through open magnetic field lines does not hold in such cases. Different models have been proposed in the last decades to explain the occasional formation of one bright large - scale transpolar arc. Thanks to a new generation of UV imagers onboard low - altitude satellites with a much higher resolution and a better luminosity sensitivity than previous global auroral imagers, a new picture of the quiet polar cap has emerged in recent years. The simultaneous occurrence of typically cusp - aligned arcs that fill the polar cap during quiet times is far more common than previously understood. Such cases cannot be explained with the help of standard transpolar arc models, where the formation of one bright polar arc has been linked (in one way or another) to IMF By induced changes in the magneto tail. In this PhD project, we want to address the question of how and why multiple polar auroral arcs emerge and fill the polar cap. In this seminar, I will present the work done so far, as well as the steps for the future.