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Context: Convectively-driven flows play a crucial role in the dynamo processes that are responsible for producing magnetic activity in stars and planets. It is still not fully understood why many astrophysical magnetic fields have a…

Solar and Stellar Astrophysics · Physics 2018-05-09 P. J. Bushby , P. J. Käpylä , Y. Masada , A. Brandenburg , B. Favier , C. Guervilly , M. J. Käpylä

For the past decade observations of the alignement of PNe symmetries with respect to the galactic disk have led to conflicting results. Recently observational evidence for alignment between PNe and local interstellar magnetic fields in the…

Astrophysics of Galaxies · Physics 2015-06-18 Diego Falceta-Goncalves , Hektor Monteiro

The origin and structure of the magnetic fields in the interstellar medium of spiral galaxies is investigated with 3D, non-ideal, compressible MHD simulations, including stratification in the galactic gravity field, differential rotation…

Astrophysics of Galaxies · Physics 2013-04-01 F. A. Gent , A. Shukurov , A. Fletcher , G. R. Sarson , M. J. Mantere

Observations of synchrotron radiation and the Faraday rotation of its polarized component allow us to investigate the magnetic properties of the diffuse interstellar medium in nearby galaxies, on scales down to roughly one hundred parsecs.…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-14 Andrew Fletcher

State of the art numerical models of the Geodynamo are still performed in a parameter regime extremely remote from the values relevant to the physics of the Earth's core. In order to establish a connection between dynamo modeling and the…

Geophysics · Physics 2015-06-18 Ludivine Oruba , Emmanuel Dormy

Understanding large scale magnetic field growth in turbulent plasmas in the magnetohydrodynamic limit is a goal of magnetic dynamo theory. In particular, assessing how well large scale helical field growth and saturation in simulations…

Plasma Physics · Physics 2015-06-15 Kiwan Park , Eric G. Blackman , Kandaswamy Subramanian

Numerical experiments of dynamo action designed to understand the generation of Earth's magnetic field produce different regime branches identified within bifurcation diagrams. Notable are distinct branches where the resultant magnetic…

Geophysics · Physics 2025-08-11 Robert J. Teed , Emmanuel Dormy

To understand solar and stellar dynamos combining local and global numerical modelling with long-term observations is a challenging task: even with state of the art computational methods and resources, the stellar parameter regime remains…

Solar and Stellar Astrophysics · Physics 2021-02-08 M. Viviani , A. Prabhu , J. Warnecke , L. Duarte , J. Pekkilä , M. Rheinhardt , M. J. Käpylä

A framework is introduced for coupling the evolution of galactic magnetic fields sustained by the mean-field dynamo with the formation and evolution of galaxies in cold dark matter cosmology. Estimates of the steady-state strength of the…

Astrophysics of Galaxies · Physics 2015-05-20 Luiz Felippe S. Rodrigues , Anvar Shukurov , Andrew Fletcher , Carlton Baugh

Solar, stellar and galactic large-scale magnetic fields are originated due to a combined action of non-uniform (differential) rotation and helical motions of plasma via mean-field dynamos. Usually, nonlinear mean-field dynamo theories take…

Solar and Stellar Astrophysics · Physics 2024-04-19 I. Rogachevskii , N. Kleeorin

We study numerically large-scale magnetic field evolution and its enhancement in gaseous disks of spiral galaxies. We consider a set of models with the various spiral pattern parameters and the initial magnetic field strength with taking…

Astrophysics of Galaxies · Physics 2018-01-31 S. A. Khoperskov , S. S. Khrapov

The magnetic field of galaxies is believed to be produced by internal dynamo action, but can be affected by motion of the galaxy through the surrounding medium. Observations of polarized radio emission of galaxies located in galaxy clusters…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 D. Moss , D. Sokoloff , R. Beck

(Abridged) Based on the rapidly increasing all-sky data of Faraday rotation measures and polarised synchrotron radiation, the Milky Way's magnetic field is now modelled with an unprecedented level of detail and complexity. We aim to…

Astrophysics of Galaxies · Physics 2015-06-17 Oliver Gressel , Detlef Elstner , Udo Ziegler

The turbulent dynamo effect, which describes the generation of magnetic fields in astrophysical objects, is described by the dynamo equation. This, in the kinematic (linear) approximation gives an unbounded exponential growth of the long…

Chaotic Dynamics · Physics 2007-05-23 Abhik Basu

Could the discrepancies found in the determination of mass in clusters of galaxies, from gravitational lensing data and from X-rays observations, be consequence of the standard description of the ICM, in which it is assumed hydrostatic…

Astrophysics · Physics 2007-05-23 D. R. Goncalves , A. C. S. Friaca

Dynamos in astrophysical disks are usually explained in terms of the standard alpha-omega mean field dynamo model where the local helicity generates a radial field component from an azimuthal field. The subsequent shearing of the radial…

Astrophysics · Physics 2015-06-24 Ethan T. Vishniac

Magnetic fields grow quickly even at early cosmological times, suggesting the action of a small-scale dynamo (SSD) in the interstellar medium of galaxies. Many studies have focused on idealized turbulent driving of the SSD. Here we simulate…

Astrophysics of Galaxies · Physics 2021-04-07 Frederick A. Gent , Mordecai-Mark Mac Low , Maarit J. Kapyla , Nishant K. Singh

Magnetic fields correlated on several kiloparsec scales are seen in spiral galaxies. Their origin could be due to amplification of a small seed field by a turbulent galactic dynamo. We critically review the current status of the galactic…

Astrophysics · Physics 2007-05-23 Kandaswamy Subramanian

The theory of large scale dynamos is reviewed with particular emphasis on the magnetic helicity constraint in the presence of closed and open boundaries. In the presence of closed or periodic boundaries, helical dynamos respond to the…

Astrophysics · Physics 2009-11-07 A. Brandenburg , W. Dobler , K. Subramanian

Star-forming dwarf galaxies can be seen as the local proxies of the high-redshift building blocks of more massive galaxies according to the current paradigm of the hierarchical galaxy formation. They are low-mass objects, and therefore…

Astrophysics of Galaxies · Physics 2015-06-18 H. Siejkowski , K. Otmianowska-Mazur , M. Soida , D. J. Bomans , M. Hanasz