Evolution of Active Regions

Living Reviews in Solar Physics

Lidia van Driel-Gesztelyi¹  Lucie May Green² 

[1] University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, U.K. and Konkoly Observatory of Hungarian Academy of Sciences, Budapest, Hungary and Observatoire de Paris, LESIA, FRE 2461(CNRS), F-92195 Meudon Principal Cedex, France;University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, U.K.;

关键词: Magnetic flux emergence;    Magnetic flux dispersion;    Active regions;   

DOI  :  10.1007/lrsp-2015-1

来源: DOAJ

【 摘 要 】

The evolution of active regions (AR) from their emergence through their long decay process is of fundamental importance in solar physics. Since large-scale flux is generated by the deep-seated dynamo, the observed characteristics of flux emergence and that of the subsequent decay provide vital clues as well as boundary conditions for dynamo models. Throughout their evolution, ARs are centres of magnetic activity, with the level and type of activity phenomena being dependent on the evolutionary stage of the AR. As new flux emerges into a pre-existing magnetic environment, its evolution leads to re-configuration of small-and large-scale magnetic connectivities. The decay process of ARs spreads the once-concentrated magnetic flux over an ever-increasing area. Though most of the flux disappears through small-scale cancellation processes, it is the remnant of large-scale AR fields that is able to reverse the polarity of the poles and build up new polar fields. In this Living Review the emphasis is put on what we have learned from observations, which is put in the context of modelling and simulation efforts when interpreting them. For another, modelling-focused Living Review on the sub-surface evolution and emergence of magnetic flux see Fan (2009). In this first version we focus on the evolution of dominantly bipolar ARs.

【 授权许可】

Unknown