Magnetosphere
A Magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields. Jupiter's moon Ganymede has a small magnetosphere — but it is situated entirely within the magnetosphere of Jupiter, leading to complex interactions. The ionospheres of weakly magnetized planets set up currents that partially deflect solar wind flow, but do not have magnetospheres, per se.
The term magnetosphere has also been used to describe regions dominated by the magnetic fields of celestial objects, e.g. Neutron Stars, Magnetars, or Pulsar magnetospheres.
In 1959 Thomas Gold proposed the name "magnetosphere", when he wrote:
- "The region above the ionosphere in which the magnetic field of the earth has a dominant control over the motions of gas and fast charged particles is known to extend out to a distance of the order of 10 earth radii; it may appropriately be called the magnetosphere [Gold, Journal of Geophysical Research, volume 64, page 1219, 1959]
