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Numerical Simulations on Origin of Galilean Moons' Magnetic AnomaliesGalileo mission detected the magnetic anomalies originated from Galilean moons. These anomalies are likely generated in the moons interiors, under the influence of a strong ambient Jovian field. Among various possible generation mechanisms of the anomalies, we focus on magneto-convection and dynamos in the interiors via numerical simulation. To mimic the electromagnetic environment of the moons, we introduce in our numerical model an external uniform magnetic field B(sub 0) with a fixed orientation but varying field strength. Our results show that a finite B(sub 0) can substantially alter the dynamo processes inside the core. When the ambient field strength B(sub 0) increases to approximately 40% of the field generated by the pure dynamo action, the convective state in the core changes significantly: the convective flow decreases by 80% in magnitude, but the differential rotation becomes stronger in much of the fluid layer, leading to a stronger field generated in the core. The field morphologies inside the core tend to align with the ambient field, while the flow patterns show the symmetry-breaking effect under the influence of B(sub 0). Furthermore, the generated field tends to be temporally more stable.
Document ID
20120011787
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Jiao, LiQuo
(Academia Sinica Beijing, China)
Kuang, WeiJia
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Ma, ShiZhuang
(Academia Sinica Beijing, China)
Date Acquired
August 26, 2013
Publication Date
November 1, 2011
Publication Information
Publication: Science China Earth Sciences
Volume: 54
Issue: 11
Subject Category
Space Sciences (General)
Report/Patent Number
GSFC.JA.01180.2012
Funding Number(s)
CONTRACT_GRANT: NNSF 40328006
Distribution Limits
Public
Copyright
Other

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