currents in its outer core. At the surface,
about 90% of the field
can be described by a simple dipole field tilting
about 10° from the rotation
axis. The currents in the Earth's core are slowly varying
causing slow
changes of the magnetic field, typically on timescales of years and
ages.
A flow of
charged particles from the
sun,
called the solar wind, hits steadily the magnetic field and
bends
/weather/articles/nr/2549