Axisymmetric dynamo action produced by differential rotation, with anisotropic electrical conductivity and anisotropic magnetic permeability
| Autor: | Franck Plunian, Thierry Alboussière |
|---|---|
| Přispěvatelé: | Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2021 |
| Předmět: |
Physics
Condensed matter physics Isotropy Rotational symmetry FOS: Physical sciences plasma instabilities 010502 geochemistry & geophysics Condensed Matter Physics 01 natural sciences Physics - Plasma Physics Physics::Geophysics Physics::Fluid Dynamics Plasma Physics (physics.plasm-ph) Electrical resistivity and conductivity [SDU]Sciences of the Universe [physics] 0103 physical sciences Dynamo theory Differential rotation Astrophysics::Solar and Stellar Astrophysics 010306 general physics Anisotropy Current density 0105 earth and related environmental sciences Dynamo |
| Zdroj: | Journal of Plasma Physics Journal of Plasma Physics, 2021, 87, ⟨10.1017/S0022377820001634⟩ |
| DOI: | 10.48550/arxiv.2102.04343 |
| Popis: | The effect on dynamo action of an anisotropic electrical conductivity conjugated to an anisotropic magnetic permeability is considered. Not only is the dynamo fully axisymmetric, but it requires only a simple differential rotation, which twice challenges the well-established dynamo theory. Stability analysis is conducted entirely analytically, leading to an explicit expression of the dynamo threshold. The results show a competition between the anisotropy of electrical conductivity and that of magnetic permeability, the dynamo effect becoming impossible if the two anisotropies are identical. For isotropic electrical conductivity, Cowling's neutral point argument does imply the absence of an azimuthal component of current density, but does not prevent the dynamo effect as long as the magnetic permeability is anisotropic. Comment: 19 pages, 6 figures |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|