MAGNETOSPHERE
Because of the nature of the Earth’s
core, the Earth is surrounded by a magnetic field. This field contains field
lines that arc in oval patterns from the magnetic poles (Seen below).The solar
wind deforms the shape of the magnetic field, however. On the sunny side of
the Earth, which is receiving the solar wind directly compresses closer to the
earth. On the dark side the opposite occurs. A tail (magnetotail) extends outward
away from the sun. The magnetotail is where most of the plasmafrom of of the
solar wind enters Earth’s magnetic field (Bottom). Now once inside the
magnetosphere the electrons follow the magnetic field lines discussed earlier.
The field lines act as wires for electricity to flow. Since the magnetic field
lines all end at the magnetic poles, most of the aurora sightings occur near
the poles. The speeding electrons along the magnetic field lines eventually
reach the Earth’s atmosphere—specifically the outer layer or Ionosphere.
In the Ionosphere the electrons collide with gas atoms, which are composed of
mainly hydrogen, oxygen and nitrogen. These collisions are what cause the Aurora
and to further understand the process we need to look at quantum leaps.
Photo's: Top: taken from http://www.exploratorium.edu/learning_studio/auroras/happen.html
Bottom: http://www.imv.uit.no/english/science/publicat/waynorth/wn1/part06.htm)