Pointwise vanishing velocity helicity of a flow does not preclude magnetic field generation.

Autor: Andrievsky A; Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Science, 84/32 Profsoyuznaya Street, 117997 Moscow, Russian Federation., Chertovskih R; Research Center for Systems and Technologies (SYSTEC), Faculty of Engineering, University of Porto, Rua Drive Roberto Frias, s/n, 4200-465, Porto, Portugal., Zheligovsky V; Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Science, 84/32 Profsoyuznaya Street, 117997 Moscow, Russian Federation.
Jazyk: angličtina
Zdroj: Physical review. E [Phys Rev E] 2019 Mar; Vol. 99 (3-1), pp. 033204.
DOI: 10.1103/PhysRevE.99.033204
Abstrakt: Pointwise zero velocity helicity density is shown not to prevent steady flows from acting as kinematic dynamos. We present numerical evidences that such flows can generate both small-scale magnetic fields as well as, by the magnetic α-effect or negative eddy diffusivity mechanisms, large-scale ones. The flows are constructed as curls of analytically defined space-periodic steady solenoidal flows, whose vorticity helicity (i.e., kinetic helicity) density is everywhere zero.
Databáze: MEDLINE