Dynamos in planets, stars and galaxies

  title={Dynamos in planets, stars and galaxies},
  author={Nigel Oscar Weiss},
  journal={Astronomy \& Geophysics},
  • N. Weiss
  • Published 1 June 2002
  • Physics, Geology
  • Astronomy & Geophysics
Nigel Weiss discusses dynamos in settings as diverse as galaxies and planets in this his 2000 Presidential Address to the Ordinary (A&G) Meeting of the Royal Astronomical Society. Abstract Global magnetic fields in the Earth and other major planets, in the Sun and other active stars, and also in spiral galaxies like the Milky Way, are apparently maintained by hydromagnetic dynamos. This lecture will contrast the various dynamo models that have been put forward. Powerful supercomputers… 
Kinematic dynamo onset and magnetic field saturation in rotating spherical Couette and periodic box simulations
Magnetic fields are ubiquitous in the universe and can be found in celestial bodies, galaxies, stars including our Sun and planets like the Earth or Jupiter. Due to the fact that at least in the
Stellar Convection and Magnetism across the H-R diagram: Theory and Models
Stars constitute undoublty one of the elementary blocks of the Universe and play as such a central role in determining for instance its chemical evolution. They can be seen as modern physics
Dynamo theories
  • F. Rincon
  • Physics
    Journal of Plasma Physics
  • 2019
These lecture notes are based on a tutorial given in 2017 at a plasma physics winter school in Les Houches. Their aim is to provide a self-contained graduate-student level introduction to the theory
Solar Forcing of Climate. 1: Solar Variability
  • C. Jager
  • Physics, Environmental Science
  • 2005
We describe the properties of the Sun, those of its Active Regions (Centres of Activity, ARs or CAs) and the 11 and 22-year cycles as observed via the variable numbers of sunspots. We describe the
Mean-field view on geodynamo models
Mean-field theory provides a useful description of magnetohydrodynamic processes leading to large-scale magnetic fields in various cosmic objects. In mean-field theory, the coefficients occurring in
The Origin of Geomagnetic Fields and the Cause of Its Reversal
People's knowledge and utilization of geomagnetic field has been going on for thousands of years, and many hypotheses have been proposed about the origin of geomagnetic field, yet so far none of them
Solar activity and its influence on climate
Solar activity, as manifested by its many equatorial as well as high-latitude components of short-term variability is regulated by the Sun’s dynamo. This constitutes an intricate interplay between
Mass and Energy Densities of the Cosmos
Fundamental principles of classical (Newtonian) physics are employed to probe the cosmological lambda Λ; it yields the values ρvac = 2.61 x 10-39 g cm-3 and Λ = 4.87 x 10-66 cm-2. It is revealed that
Mean-field concept and direct numerical simulations of rotating magnetoconvection and the geodynamo
Mean-field theory describes magnetohydrodynamic processes leading to large-scale magnetic fields in various cosmic objects. In this study magnetoconvection and dynamo processes in a rotating


Galactic Magnetism: Recent developments and perspectives
▪ Abstract We discuss current observational and theoretical knowledge of magnetic fields, especially the large-scale structure in the disks and halos of spiral galaxies. Among other topics, we
A Critical Review of Galactic Dynamos
▪ Abstract I present the general picture of how galactic magnetic fields grow in disks according to the alpha-Omega dynamo theory. Emphasis is placed on following the lines of force during the dynamo
Stellar Astrophysical Fluid Dynamics: Contents
In all phases of the life of a star, hydrodynamical processes play a major role. This volume gives a comprehensive overview of the current state of knowledge in stellar astrophysical fluid dynamics,
Lectures on solar and planetary dynamos
Introduction 1. Fundamentals of dynamo theory P. H. Roberts 2. Solar and stellar dynamics N. O. Weiss 3. Convection and magnetoconvection in a rapidly rotating sphere M. R. E. Proctor 4. Solar
Magnetic fields in normal galaxies
  • R. Beck
  • Physics
    Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences
  • 2000
Linearly polarized radio continuum emission is a powerful tool for studying the strength and structure of interstellar magnetic fields in galaxies. Interstellar magnetic fields with a well–ordered
Modulation and symmetry changes in stellar dynamos
Stellar dynamos are governed by non-linear partial differential equations (PDEs) which admit solutions with dipole, quadrupole or mixed symmetry (i.e. with different parities). These PDEs possess
Solar dynamo theory : Solar dynamo theory: a new look at the origin of small-scale magnetic fields
Fausto Cattaneo and David W Hughes delve beneath the surface of the Sun with numerical models of turbulent convection. Although magnetic dynamo action is traditionally associated with
What is a stellar dynamo
Numerical simulations of turbulent stellar dynamos are now feasible. The characteristic time-scale for kinematic behaviour is related to the turnover time of the turbulent eddies. Results from
Dynamo-generated Turbulence and Large-Scale Magnetic Fields in a Keplerian Shear Flow
The nonlinear evolution of magnetized Keplerian shear ows is simulated in a local, three-dimensional model, including the eeects of compressibility and stratiication. Supersonic ows are initially
Dynamo–generated turbulence and outflows from accretion discs
  • A. Brandenburg
  • Physics
    Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences
  • 2000
Local hydromagnetic simulations of accretion–disc turbulence currently provide the most convincing evidence that the origin of turbulence in discs could be the Balbus–Hawley magnetorotational