On the Origin of the Galactic Magnetic Field
| dc.creator | Vishniac, Ethan T. | |
| dc.date | 1992-10-30 | |
| dc.date.accessioned | 2026-07-07T02:18:43Z | |
| dc.date.available | 2026-07-07T02:18:43Z | |
| dc.description | The galactic magnetic field is commonly supposed to be due to a dynamo acting on some large scale seed field. A major difficulty with this idea is that estimates of reasonable seed field strengths tend to be quite low, on the order of $\sim10^{-20}$ gauss. Here we examine the contribution due to the flux entrained in winds from protostars formed in the first dynamo e-folding time of a galaxy's existence. Using a minimal estimate of a protostellar magnetic field we find that if each protostar ejects a single current ring, sufficient to maintain flux freezing in the wind, than the large scale average dipole field from all such current rings will be at least 5 orders of magnitude larger than previous seed field estimates. Allowing for a reasonable amount of magnetic activity in protostars during an extended period of mass loss increases this to a dipole seed field of $\sim10^{-12}$ gauss. For the purposes of producing a seed field it is irrelevant whether or not this initial injection of flux takes place in a newly formed galactic disk, or in star forming proto-galactic clouds. The compression of this dipole field into a thin disk will lead to a large scale $B_r\sim 10^{-10.5}$ gauss. Initially, field strengths on smaller scales will be larger, but nowhere near current levels. | |
| dc.description | 20 pages | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9210006 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9210006 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/9592 | |
| dc.subject | Astrophysics | |
| dc.title | On the Origin of the Galactic Magnetic Field | |
| dc.type | text |