- Ring current
A ring current is an
electric current carried by charged particles trapped in a planet'smagnetosphere . It is caused by the longitudinal drift of energetic (10–200 keV) particles.Earth's ring current
Earth 's ring current is responsible for shielding the lower latitudes of the Earth from magnetospheric electric fields. It therefore has a large effect on the electrodynamics ofgeomagnetic storm s. The ring current system consists of a band, at a distance of 3 to 5 "R"E(1), which lies in the equatorial plane and circulates clockwise around the Earth (when viewed from thenorth ). The particles of this region produce a magnetic field in opposition to theEarth's magnetic field and so an Earthly observer would observe a decrease in themagnetic field in this area.The ring current energy is mainly carried around by the ions, most of which are protons. However, one also sees alpha particles in the ring current, a type of ion that is plentiful in the solar wind. In addition, a certain percentage are O+ oxygen ions, similar to those in the ionosphere of Earth, though much more energetic. This mixture of ions suggests that ring current particles probably come from more than one source. Ring current particle energies range from 0.05 MeV to 1 MeV.
The ring current and geomagnetic storms
During a
geomagnetic storm , the number of particles in the ring current will increase. As a result there is a decrease in the effects of geomagnetic field.See also
*
Van Allen radiation belt References
* 1 --
Introduction to Geomagnetically Trapped Radiation byMartin Walt 1994
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