Magnetoconvection Dynamos and the Magnetic Fields of Io and Ganymede
G. R. Sarson,
C. A. Jones,
K. Zhang,
G. Schubert
Data from the Galileo orbiter suggest that two of Jupiter's moons,
Io and Ganymede, have intrinsic magnetic fields. The magnetic field of
Jupiter alters the nature of the magnetohydrodynamic processes
generating these intrinsic fields. Such an imposed field allows
appreciable internal fields to be generated in cases where convection
cannot otherwise maintain a dynamo. The dipole moment of the internal
field can then become aligned with the background field, as is observed
for Io and Ganymede. Io might not have a self-sustained intrinsic field
in the absence of the ambient jovian field; Ganymede is almost
certainly operating as a dynamo in its own right.
G. R. Sarson, C. A. Jones, K. Zhang, Department of Mathematics,
University of Exeter, Exeter EX4 4QE, UK.
G. Schubert, Department of Earth and Space Sciences, Institute of
Geophysics and Planetary Physics, University of California, Los
Angeles, CA 90095, USA.