The Magnetic Field of Ganymede: Fossil or Vital Sign? (original) (raw)
The strong magnetic field detected around Ganymede by the Galileo probe has caused many to conclude that Ganymede possesses a working dynamo, despite the inherent difficulties in keeping the core of Ganymede partly molten over >4 Ga and other problems. This paper explores the possibility of remanent magnetism of the outer solid portion of Ganymede as a major component of the observed field by examining and correcting the mathematical treatments of magnetization of exterior shells by past interior dynamos by Runcorn (1975) and Crary and Bagenal (1998). Although errors and hidden assumptions were present in both derivations, the conclusion of Crary and Bagenal that an exterior remanent field would remain after shutdown of an interior dynamo given an adequately high magnetizability of the shell remains valid.
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