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GEOPHYSICAL RESEARCH LETTERS,
VOL. 36,
L24202,
4 PP., 2009
doi:10.1029/2009GL041221
Thermal core-mantle coupling in an early lunar dynamo: Implications for a global magnetic field and magnetosphere of the early Moon
Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, Japan
Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, Japan
A theoretical model suggests a short-lived lunar dynamo driven by a mantle overturn forming crustal thickness dichotomy, while the lunar paleomagnetic data and crustal magnetic fields suggest both of presence and absence of a global magnetic field of the Moon ∼4 billion years (Gyr) ago. Here we carry out numerical simulations of a possible lunar dynamo, including effects of mantle overturn on heat flux heterogeneity at the core-mantle boundary. As a result, the surface field intensity of the lunar dynamo is about 100 nT. In this case, a lunar magnetosphere could be present with a sunward size of 1.4 times the Moon's radius. Considering the 4.6 Gyr orbit evolution of the Moon, the magnetic field intensity and the magnetosphere size could be larger, suggesting the lunar crustal magnetization acquired in the ancient dynamo field.
Received 5 October 2009; accepted 23 November 2009; published 23 December 2009.
Citation: (2009), Thermal core-mantle coupling in an early lunar dynamo: Implications for a global magnetic field and magnetosphere of the early Moon, Geophys. Res. Lett., 36, L24202, doi:10.1029/2009GL041221.
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