| Term: | cusp |
| Definition: |
In the magnetosphere, two regions near magnetic local noon and approximately 15 degrees of latitude equatorward of the north and the south magnetic poles. The cusps mark the division between geomagnetic field lines on the sunward side (which are approximately dipolar but somewhat compressed by the solar wind) and the field lines in the polar cap that are swept back into the magnetotail by the solar wind. |