The auroral oval is the footprint in the atmosphere of the boundary between the highly stretched field lines of the polar cap and the more normal field lines at lower latitudes. When the solar wind blows hard, this boundary moves equatorward as more high latitude field lines are blown out into the tail, at times moving the aurora as far equatorward as Huntsville, Tel Aviv, or Kyoto.

In the near-noon sector, known as the "cusp", auroral zone field lines incline and curve so as to point directly into the solar wind at the boundary, acting like "pitot tubes" that channel solar plasma all the way down to the ionosphere. Following the auroral zone away from noon is equivalent to following the magnetospheric boundary layer along its "flanks" and into the turbulent wake region in the tail. With a little imagination, these features can be visualized in an image of the auroral oval from space. At all local times, the auroral zone is a region of heating and strong winds in the ionosphere and upper atmosphere.