Magnetic helicity and fluxes in an inhomogeneous alpha squared dynamo

Abstract

Much work on turbulent three-dimensional dynamos has been done using triply periodic domains, in which there are no magnetic helicity fluxes. Here we present simulations where the turbulent intensity is still nearly homogeneous, but now there is a perfect conductor boundary condition on one end and a vertical field or pseudo-vacuum condition on the other. This leads to migratory dynamo waves. Good agreement with a corresponding analytically solvable alpha^2 dynamo is found. Magnetic helicity fluxes are studied in both types of models. It is found that at moderate magnetic Reynolds numbers, most of the magnetic helicity losses occur at large scales. Whether this changes at even larger magnetic Reynolds numbers, as required for alleviating the catastrophic dynamo quenching problem, remains still unclear.

11 pages, figures, 2 tables, Astron. Nachr. (in press)

References in corpus (7)

• Kinematic alpha effect in isotropic turbulence simulations
• Small-scale magnetic helicity losses from a mean-field dynamo
• Turbulent dynamo with advective magnetic helicity flux
• Magnetic helicity fluxes in an alpha-squared dynamo embedded in a halo
• Traces of large-scale dynamo action in the kinematic stage
• Magnetic helicity flux in the presence of shear
• Analytic solution of an oscillatory migratory alpha^2 stellar dynamo

Cited by in corpus (1)

• Magnetic helicity dissipation and production in an ideal MHD code