polar cusp

The polar cusp is a region in Earth's magnetosphere where magnetic field lines split on the dayside. These field lines originate from high latitudes, with some crossing the equator and others passing over the polar caps. The projection of these polar cusps onto the atmosphere at approximately 72° magnetic latitude creates the dayside auroral ovals. While auroras can be observed in these regions during winter nights, they are less intense than those on the nightside due to the lower energy of the particles involved. The polar cusp is a key area where the solar wind interacts with Earth's magnetic field.12