Fluctuations of electrical conductivity: a new source for astrophysical magnetic fields
Fluid Dynamics
2016-05-04 v1 Earth and Planetary Astrophysics
Plasma Physics
Abstract
We consider the generation of magnetic field by the flow of a fluid for which the electrical conductivity is nonuniform. A new amplification mechanism is found which leads to dynamo action for flows much simpler than those considered so far. In particular, the fluctuations of the electrical conductivity provide a way to bypass anti-dynamo theorems. For astrophysical objects, we show through three-dimensional global numerical simulations that the temperature-driven fluctuations of the electrical conductivity can amplify an otherwise decaying large scale equatorial dipolar field. This effect could play a role for the generation of the unusually tilted magnetic field of the iced giants Neptune and Uranus.
Keywords
Cite
@article{arxiv.1604.00469,
title = {Fluctuations of electrical conductivity: a new source for astrophysical magnetic fields},
author = {Francois Petrelis and Alexandros Alexakis and Christophe Gissinger},
journal= {arXiv preprint arXiv:1604.00469},
year = {2016}
}
Comments
Accepted in Phys.Rev.Lett