The following image is an artist’s impression of the solar wind and the magnetosphere.
The magnetosphere is a dough-nut shaped field around the Earth and is caused by the
interaction of the Earth’s magnetic field with the solar wind emanating from the
Image courtesy NASA
The sun-ward side of the magnetosphere is compressed by the solar wind, and the pressure
on it varies with the magnitude of solar flares. The magnetosphere on the dark side
of the Earth extends a long way out from it.
Lines of magnetic force around the Earth exist between the two magnetic poles, one
in the north and the other in the south, at the auroral areas.
The Mechanism for Planetary Growth
Some of the cosmic dust, being pulled on its journey towards the Sun, may come into
the vicinity of the Earth’s magnetic field. Photo-ionisation, caused by the ultraviolet
energy of the solar wind, takes place constantly on the surface of these cosmic particles
and a stream of ions are released. Because these ions are charged, they are affected
by the Earth’s magnetic field and confined to layered belts around the Earth, depending
upon their energy levels. These layers are known as the Outer Van Allen Belt, the
Inner Van Allen Belt, and the Ionosphere. The Inner Van Allen Belt is 4000 to 9500
km from the surface of the Earth, depending upon its latitude position. In what is
known as the South Atlantic Anomaly (off the coast of Argentina) it dips down towards
When there are solar flares, the bow wave of the solar wind acting on the Earth’s
magnetosphere pushes the inner Van Allen Belt further in towards the ionosphere.
This phenomenon was first recognised by Chapman and Ferraro in 1958. It is likely
that when this happens, ions are dumped into the ionosphere.
From here negatively charged ions may eventually get jetted into the Earth’s crust
at the Aurora borealis area, pulled by magnetic forces from beneath the crust. Similarly
positive ions may get pulled into the southern equivalent, the Aurora Australis.