Virtual Nordic Dynamo Seminar

Axisymmetric dynamo action is possible with anisotropic conductivity

Name: Axisymmetric dynamo action is possible with anisotropic conductivity
Start: 2020-05-05T15:00:00+02:00
End: 2020-05-05T16:00:00+02:00
Location: No location set

by Franck Plunian

Tuesday 5 May 2020, 15:00 → 16:00 Europe/Stockholm

Description

https://stockholmuniversity.zoom.us/j/940229961

10.1103/PhysRevResearch.2.013321

A milestone of dynamo theory is Cowling's theorem, known in its modern form as the impossibility for an axisymmetric velocity field to generate an axisymmetric magnetic field by dynamo action. Using an anisotropic electrical conductivity we show that an axisymmetric dynamo is in fact possible with a motion as simple as solid body rotation. On top of that the instability analysis can be conducted entirely analytically, leading to an explicit expression of the dynamo threshold which is the only example in dynamo theory.