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ring current

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ring current

An electric current flowing westward around the Earth; it arises from a net eastward flow of electrons and a net westward flow of protons trapped inside the Van Allen radiation belts. The current produces a magnetic field that cancels part of the geomagnetic field at the Earth's surface. During geomagnetic storms, when the Van Allen belts are recharged with particles, the increased ring current results in a further decrease of the Earth's surface magnetic field strength.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

ring current

[′riŋ ‚kə·rənt]
(geophysics)
A westward electric current which is believed to circle the earth at an altitude of several earth radii during the main phase of geomagnetic storms, resulting in a large worldwide decrease in the geomagnetic field horizontal component at low latitudes.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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References in periodicals archive
NICS is comprehensively used to express the aromaticity of molecules because it can clearly and simply monitor the condition of ring current. Aromatic systems have pretty negative NICS values, antiaromatic systems have strongly positive NICS values, and nonaromatic cyclic systems should have NICS values close to zero [35,42-44].
In this study we will analyze several intervals of electromagnetic ion cyclotron (EMIC) wave activity observed by these spacecraft, as well as simultaneous variations in ring current fluxes and cold plasma.
However, the X-ray flux from very energetic flares causes sufficient change to the level of ionisation (and thus conductivity) of the ionosphere that the normal ring current flowing around the Earth is also disturbed.
The up-field shifts of both tetrapyrrole-H and tetraphenyl-H in [K.sup.+]- or Ca- bound [TPPS.sub.4] are mainly due to electrostatic interaction between porphyrin-core and metal ion, and such interaction reduces the "ring current" on both tetrapyrrole and tetraphenyl (because of their co-planar conjugation), increasing the nuclear shielding of all these protons.
In a magnetic storm the Van Allen radiation belts (the charged plasma particles surrounding the Earth) are rearranged, creating a doughnut that carries a ring current of 100 kiloelectronvolt plasma around the Earth.
After a brief historical review of early ring current studies, 32 papers on the physics and structures of the earth's inner magnetosphere are organized into sections that deal with the sources and losses of plasma and energetic particles in the inner magnetosphere, energetic particle acceleration mechanisms, external driving mechanisms of the inner magnetosphere, observational aspects of inner magnetosphere dynamics, and large-scale modeling efforts of the inner magnetosphere.
In so doing, it creates a strong electric current, or ring current, which partially girdles the magnetosphere's equator and is much greater on Earth's nightside than dayside.
On July 20, the high-field superconducting ring, which will be magnetically levitated for several hours in a large vacuum vessel, was tested to a total ring current of 1.57 million amperes.
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