geodynamon.
/ˌdʒiːə(ʊ)ˈdʌɪnəməʊ/, /dʒɪəˈdʌɪnəməʊ/, U.S. /ˌdʒioʊˈdaɪnəˌmoʊ/ Geology.
The mechanism by which the earth's magnetic field is generated, believed to resemble a self-exciting dynamo and to involve circulatory and convective motions and electrical currents within the earth's liquid outer core.
ΚΠ
1967 Jrnl. Fluid Mech. 28 795 The earth will also have a boundary region where the toroidal magnetic field almost vanishes, for the geodynamo must close most of its current paths within the core.
1987 J. Gleick Chaos i. 29 The ‘geodynamo’ is known to have flipped many times during the earth's history, at intervals that seem erratic and inexplicable.
1991 Computer Bull. Apr. 14/2 Maps of the field strength at the core–mantle boundary..can also be predicted from theoretical models of the geodynamo process.
2002 Geophysics in UK (Royal Astron. Soc.) 26/1 The mechanism of the self-sustained dynamo action responsible—known as the geodynamo—has long been a matter of debate.
This is a new entry (OED Third Edition, March 2012; most recently modified version published online March 2022).
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n.1967