Editing Ring current

{{Short description|Atmospheric effect in a planet's magnetosphere}}
{{About|an atmospheric effect|the effect in nuclear magnetic resonance|Aromatic ring current}}
A '''ring current''' is an [[electric current]] carried by charged particles trapped in a planet's [[magnetosphere]]. It is caused by the longitudinal drift of energetic (10&ndash;200 k[[electron volt|eV]]) particles.

==Earth's ring current==
[[File:Currents.jpg|thumb|right|300px|Schematic view of the different current systems which shape the Earth's [[magnetosphere]].]]
[[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 of [[geomagnetic storm]]s. The ring current system consists of a band, at a distance of 3 to 8 [[Earth radius|''R''<sub>E</sub>]],<ref>{{cite journal|author=I. A. Daglis |author2=R. M. Thorne |author3=W. Baumjohann |author4=S. Orsini |name-list-style=amp |title=The terrestrial ring current: Origin, formation, and decay |date=November 1999 |journal=Reviews of Geophysics |volume=37 |issue=4 |pages=407–438 |doi=10.1029/1999RG900009 |bibcode=1999RvGeo..37..407D|doi-access=free }}</ref> which lies in the [[celestial sphere|equatorial plane]] and circulates clockwise around the Earth (when viewed from the north). The particles of this region produce a magnetic field in opposition to the [[Earth's magnetic field]] and so an Earthly observer would observe a decrease in the [[magnetic field]] in this area.<ref name="Merrill2010">{{cite book|author=Ronald T. Merrill|title=Our Magnetic Earth: The Science of Geomagnetism|date=15 November 2010|publisher=[[University of Chicago Press]]|isbn=978-0-226-52050-6}}</ref>{{rp|135}} The negative deflection of the Earth's magnetic field due to the ring current is measured by the [[Dst index]].

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<sup>+</sup> 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.{{Citation needed|date=March 2023}}

==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 [[Earth's magnetic field|geomagnetic field]].

== See also ==
* [[Van Allen radiation belt]]

== References ==
{{Reflist}}
* {{cite journal| doi= 10.1023/B:SPAC.0000007516.10433.ad| title= Ring Current Energy Input and Decay |journal= Space Science Reviews |volume= 109| issue= 1–4 |pages= 105–131 |date= 2003 |author= Janet U. Kozyra |author-link1=Janet Kozyra|author2= Michael W. Liemohn |name-list-style= amp |bibcode = 2003SSRv..109..105K |url= http://www-personal.umich.edu/~liemohn/Reprints/Kozyra_SSR_2003.pdf |hdl= 2027.42/43761 | s2cid= 53598767 |hdl-access= free }}

{{Magnetosphere}}

[[Category:Geophysics]]
[[Category:Space science]]
[[Category:Space plasmas]]


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