(from the article `geomagnetic field`) ...rings the ionosphere is constantly bombarded by particles that ionize the atmosphere and generate auroras. Because auroras are almost always ... The topology of magnetic field lines produced by the reconnection process accounts for the existence of auroral ovals. Field lines of the polar caps .....
Found on
http://www.britannica.com/eb/a-z/a/125
An oval band around each geomagnetic pole which is the locus of structured AURORAe.
Found on
http://www.encyclo.co.uk/visitor-contributions.php
No exact match found.
