Hi Kathy!

That's a very interesting question! The aurora borealis (northern lights) and aurora australis (southern lights) actually don't occur right at the Earth's north and south magnetic poles. Instead, they occur in two rings around the magnetic poles, one in the northern hemisphere and one in the southern hemisphere. We call these rings the "auroral ovals." You can see a map of what the auroral ovals look like now based upon electron measurements from the NOAA POES satellites here: http://www.swpc.noaa.gov/pmap/

The reason why the auroras occur in rings around the north and south magnetic poles of the Earth is connected to the structure of the Earth's magnetosphere and the interaction of the magnetosphere with the solar wind. If you could follow one of the magnetic field lines in the night side auroral oval away from the Earth out into space, you would find yourself in a region scientists call the plasma sheet. Based upon satellite observations of magnetic fields and electrons in the Earth's magnetosphere, scientists now believe that brilliant auroral displays are related to physical processes in the plasma sheet that can generatehuge electrical currents in the magnetosphere and accelerate electrons.

Kris