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Department of Mathematical Sciences


Publication details for Anthony Yeates

Yeates, A.R. & Munoz-Jaramillo, A. (2013). Kinematic active region formation in a three-dimensional solar dynamo model. Monthly Notices of the Royal Astronomical Society 436(4): 3366-3379.

Author(s) from Durham


We propose a phenomenological technique for modelling the emergence of active regions
within a three-dimensional, kinematic dynamo framework. By imposing localized velocity
perturbations, we create emergent flux tubes out of toroidal magnetic field at the base of the
convection zone, leading to the eruption of active regions at the solar surface. The velocity
perturbations are calibrated to reproduce observed active region properties (including the size
and flux of active regions, and the distribution of tilt angle with latitude), resulting in a more
consistent treatment of flux-tube emergence in kinematic dynamo models than artificial flux
deposition. We demonstrate how this technique can be used to assimilate observations and
drive a kinematic three-dimensional model, and use it to study the characteristics of active
region emergence and decay as a source of poloidal field.We find that the poloidal components
are strongest not at the solar surface, but in the middle convection zone, in contrast with the
common assumption that the poloidal source is located near the solar surface. We also find
that, while most of the energy is contained in the lower convection zone, there is a good
correlation between the evolution of the surface and interior magnetic fields.


Published on behalf of The Royal Astronomical Society