Volume 83, Number 5, September 2008
Article Number 59001
Number of page(s) 5
Section Geophysics, Astronomy and Astrophysics
Published online 02 September 2008
EPL, 83 (2008) 59001
DOI: 10.1209/0295-5075/83/59001

Relations between the dynamo region geometry and the magnetic behavior of stars and planets

L. Goudard and E. Dormy

MAG (IPGP & ENS), CNRS UMR7154, LRA Département de Physique - 24 rue Lhomond, 75005 Paris France, EU

received 22 April 2008; accepted in final form 16 July 2008; published September 2008
published online 2 September 2008

The geo and solar magnetic fields have long been thought to be very different objects both in terms of spatial structure and temporal behavior. The recently discovered field structure of a fully convective star is more reminiscent of planetary magnetic fields than the Sun's magnetic field (DONATI J.-F. et al., Science, 311 (2006) 633), despite the fact that the physical and chemical properties of these objects clearly differ. This observation suggests that a simple controlling parameter could be responsible for these different behaviors. We report here the results of three-dimensional simulations which show that varying the aspect ratio of the active dynamo region can yield a sharp transition from Earth-like steady dynamos to Sun-like dynamo waves.

91.25.Cw - Origins and models of the magnetic field; dynamo theories.
47.65.-d - Magnetohydrodynamics and electrohydrodynamics.

© EPLA 2008