Generation of the magnetic field in jets
Abstract
We consider dynamo action under the combined influence of turbulence and large-scale shear in sheared jets. Shear can stretch turbulent magnetic field lines in such a way that even turbulent motions showing mirror symmetry become suitable for generation of a large-scale magnetic field. We derive the integral induction equation governing the behaviour of the mean field in jets. The main result is that sheared jets may generate a large-scale magnetic field if shear is sufficiently strong. The generated mean field is mainly concentrated in a magnetic sheath surrounding the central region of a jet, and it exhibits sign reversals in the direction of the jet axis. Typically, the magnetic field in a sheath is dominated by the component along the jet that can reach equipartition with the kinetic energy of particles, The field in the central region of jets has a more disordered structure.
Cite
@article{arxiv.astro-ph/0605562,
title = {Generation of the magnetic field in jets},
author = {V. Urpin},
journal= {arXiv preprint arXiv:astro-ph/0605562},
year = {2009}
}
Comments
7 pages, accepted for publication in A&A