Simulations of galactic dynamos
arXiv:1402.0212 · doi:10.1007/978-3-662-44625-6_19
Abstract
We review our current understanding of galactic dynamo theory, paying particular attention to numerical simulations both of the mean-field equations and the original three-dimensional equations relevant to describing the magnetic field evolution for a turbulent flow. We emphasize the theoretical difficulties in explaining non-axisymmetric magnetic fields in galaxies and discuss the observational basis for such results in terms of rotation measure analysis. Next, we discuss nonlinear theory, the role of magnetic helicity conservation and magnetic helicity fluxes. This leads to the possibility that galactic magnetic fields may be bi-helical, with opposite signs of helicity and large and small length scales. We discuss their observational signatures and close by discussing the possibilities of explaining the origin of primordial magnetic fields.
28 pages, 15 figure, to appear in Lecture Notes in Physics "Magnetic fields in diffuse media", Eds. E. de Gouveia Dal Pino and A. Lazarian
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Cited by in corpus (8)
- Dynamo theories
- Magnetorotational instability and dynamo action in gravitoturbulent astrophysical discs
- Magnetic field evolution and reversals in spiral galaxies
- Exact axially symmetric galactic dynamos
- A dynamo amplifies the magnetic field of a Milky-Way-like galaxy
- The formation of regular interarm magnetic fields in spiral galaxies
- Turbulent Magnetic Dynamos with Halo Lags, Winds, and Jets
- Synthesizing Observations and Theory to Understand Galactic Magnetic Fields: Progress and Challenges