Fluctuations of electrical conductivity: a new source for astrophysical magnetic fields [CL]

http://arxiv.org/abs/1604.00469


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.

Read this paper on arXiv…

F. Petrelis, A. Alexakis and C. Gissinger
Tue, 5 Apr 16
35/67

Comments: Accepted in Phys.Rev.Lett