FORMATION OF AURORAL ARCS VIA MAGNETOSPHERE-IONOSPHERE COUPLING

Brilliant displays of light are visible within a polar band of latitudes that surround each of the Earth's geomagnetic poles. These emissions are known as the aurora, and they are a dramatic consequence of the electromagnetic interaction between the Sun and the Earth. Energy is carried from the Sun by the plasma of the solar wind. This plasma impinges upon the magnetic field of the Earth and powers a wide range of electrodynamical phenomena that include the aurora. The aurora itself results from electrons that first are energized at very high altitudes by the solar wind-Earth interactions and then travel down magnetic field lines until they hit the atmosphere. In this tutorial I discuss the basic physical processes that lead to the energization of these electrons and thus to the aurora.