•The ionosphere begins at a height of about 50 km
(30 miles) above the surface, but it is most distinct and important above 80
km (50 miles). In the upper regions of the ionosphere, beginning several
hundred kms above Earth’s surface and extending tens of thousands of kms into
space, is the magnetosphere, a region where the behaviour of charged particles
is strongly affected by the magnetic fields of Earth and
the Sun. The magnetosphere also contains the Van Allen radiation belts, where highly energized protons and electrons travel back
and forth between the poles of Earth’s magnetic field.