Yoshizawa's cross-helicity effect and its quenching
arXiv:1112.1237 · doi:10.1080/03091929.2012.681307
Abstract
A central quantity in mean-field magnetohydrodynamics is the mean electromotive force EMF, which in general depends on the mean magnetic field. It may however have a part independent of the mean magnetic field. Here we study an example of a rotating conducting body of turbulent fluid with non-zero cross-helicity, in which a contribution to the EMF proportional to the angular velocity occurs (Yoshizawa 1990). If the forcing is helical, it also leads to an alpha effect, and large-scale magnetic fields can be generated. For not too rapid rotation, the field configuration is such that Yoshizawa's contribution to the EMF is considerably reduced compared to the case without alpha effect. In that case, large-scale flows are also found to be generated.
10 pages, 8 figures, compatible with published version
References in corpus (7)
- Simulations of nonhelical hydromagnetic turbulence
- Test-field method for mean-field coefficients with MHD background
- Cross helicity and turbulent magnetic diffusivity in the solar convection zone
- The alpha effect with imposed and dynamo-generated magnetic fields
- Modeling the turbulent cross-helicity evolution: Production, dissipation, and transport rates
- The role of the Yoshizawa effect in the Archontis dynamo
- Mean electromotive force proportional to mean flow in mhd turbulence