HR: 12:05h
AN: GP42A-08    [Abstracts]
TI: Zonal flow dynamos
AU: * Gomez Perez, N
EM: ngomez@phys.ualberta.ca
AF: University of Alberta, Department of Physics, Edmonton, AB T6G-2J1 Canada
AU: Heimpel, M
EM: mheimpel@phys.ualberta.ca
AF: University of Alberta, Department of Physics, Edmonton, AB T6G-2J1 Canada
AB: The dynamo model describes the non-linear dynamics of the generation of magnetic field in planetary bodies. It has been widely studied for many different sets of parameters. We are studying self sustained dynamos generated at low magnetic Prantdl number. This can lead to a better understanding of the interaction between a high energy velocity field with a diffusive magnetic field. We focus on a regime in which dynamo action is sustained by zonal flows, with toroidal kinetic energy dominating the magnetic and poloidal kinetic energies. The results include dynamos with equatorial dipole fields as well as quadrupolar and octupolar fields. Our results may be applicable to Uranus and Neptune, for which dynamo action is believed to be generated in the water-methane oceans beneath the deep atmosphere. The electrical conductivity of ionically conducting liquid is orders of magnitude lower that of liquid metals. Our low-conductivity model results, for some cases, in a highly tilted dipolar field where the non dipolar components are not negligible, as is observed for Uranus and Neptune. Our models can also help us to understand Saturn's magnetic field, which may involve dynamo action seated in the transition zone from metallic to molecular hydrogen.
DE: 1510 Dynamo: theories and simulations
DE: 5734 Magnetic fields and magnetism
DE: 6255 Neptune
DE: 6275 Saturn
DE: 6293 Uranus
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005