geologia: Dynamo theory

Evidence: 100 • authority: 72

In physics, the dynamo theory proposes a mechanism by which a celestial body such as Earth or a star generates a magnetic field. The dynamo theory describes the process through which a rotating, convecting, and electrically conducting fluid can maintain a magnetic field over astronomical time scales. A dynamo is thought to be the source of the Earth's magnetic field and the magnetic fields of Mercury and the Jovian planets.

Evidence: 67 • authority: 88

An approach to a dynamic theory of dynamo action in a rotating conducting fluid. Dynamo action associated with the motion generated by a random body force f(x, t) in a conducting fluid rotating with uniform angular velocity ω is considered. It is supposed that, in the Fourier decomposition off, only waves having a phase velocity V satisfying V . ω > 0 are present and that the Fourier amplitudes of f are isotropically distributed. The resulting velocity field then lacks reflexional symmetry, and energy is transferred to a magnetic field h 0 ( x , t ) provided the scale L of h 0 is sufficiently large. Attention is focused on a particular distribution of h 0 ( x , t ) (a circularly polarized w…

Evidence: 48 • authority: 80

Spherical Oscillatory α[TSUP]2[/TSUP] Dynamo Induced by Magnetic Coupling between a Fluid Shell and an Inner Electrically Conducting Core: Relevance to the Solar Dynamo

Evidence: 48 • authority: 80

NONLINEAR DYNAMO IN A ROTATING ELECTRICALLY CONDUCTING FLUID