ring current


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.

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.