A dynamo model for axisymmetric and non-axisymmetric solar magnetic fields |
| |
Authors: | J. Jiang J. X. Wang |
| |
Affiliation: | National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China |
| |
Abstract: | More and more observations are showing a relatively weak, but persistent, non-axisymmetric magnetic field co-existing with the dominant axisymmetric field on the Sun. Its existence indicates that the non-axisymmetric magnetic field plays an important role in the origin of solar activity. A linear non-axisymmetric α2– Ω dynamo model is derived to explore the characteristics of the axisymmetric ( m = 0) and the first non-axisymmetric ( m = 1) modes and to provide a theoretical basis with which to explain the 'active longitude', 'flip-flop' and other non-axisymmetric phenomena. The model consists of an updated solar internal differential rotation, a turbulent diffusivity varying with depth, and an α-effect working at the tachocline in a rotating spherical system. The difference between the α2–Ω and the α–Ω models and the conditions that favour the non-axisymmetric modes under solar-like parameters are also presented. |
| |
Keywords: | magnetic fields MHD Sun: activity Sun: magnetic fields |
|
|