A simplified model of collision-driven dynamo action in small bodies
Geophysics
2015-06-18 v3 Earth and Planetary Astrophysics
Fluid Dynamics
Abstract
We investigate numerically the self-sustained dynamo action in a spinning sphere whose sense of rotation reverses periodically. This system serves as a simple model of a dynamo in small bodies powered by frequent collisions. It is found that dynamo action is possible in some intervals of collision rates. At high Ekman numbers the laminar spin-up flow is helical in the boundary layers and the Ekman circulation together with the azimuthal shear powers the dynamo action. At low Ekman number a non-axisymmetric instability helps the dynamo action. The intermittency of magnetic field occurs at low Ekman number.
Keywords
Cite
@article{arxiv.1311.6502,
title = {A simplified model of collision-driven dynamo action in small bodies},
author = {Xing Wei and Rainer Arlt and Andreas Tilgner},
journal= {arXiv preprint arXiv:1311.6502},
year = {2015}
}
Comments
submitted to PEPI, 16 pages, 8 figures