An Etymological Dictionary of Astronomy and Astrophysics
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Of or pertaining to → geomagnetism.

→ geo-; → magnetic.

The natural variations in the → geomagnetic field due to interactions of the Earth's field and → magnetosphere with energetic particles from the Sun.

→ geomagnetic; → activity.

A geophysical event, distinguished from the → magnetic reversal, in which the Earth's magnetic field departs for a relatively short time from its usual near axial configuration, without establishing a reversed direction. During the excursion the intensity and direction of the Earth's magnetic field undergo drastic changes. Palaeomagnetic measurements have revealed that since the last full reversal the Earth's magnetic field has, for brief intervals, deviated from the behavior expected during "normal" secular variation.

→ geomagnetic; → excursion.

The magnetic field that is generated within the Earth and extends out around the Earth. The intensity of the magnetic field at the Earth's surface is about 0.32 → gauss at the equator and 0.62 gauss at the north pole.

→ geomagnetic; → field.

A violent disturbance of the Earth's magnetic field, distinct from regular diurnal variations, following a → solar flare or → coronal mass ejection.

→ geomagnetic; → storm.