Dynamo saturation in rapidly rotating solar-type stars  

作　　者：Leonid L.Kitchatinov Serge V.Olemskoy 

机构地区：[1]Institute for Solar-Terrestrial Physics [2]Pulkovo Astronomical Observatory

出　　处：《Research in Astronomy and Astrophysics》2015年第11期1801-1812,共12页天文和天体物理学研究（英文版）

基　　金：supported by the Russian Foundation for Basic Research (project No. 13-02-00277)

摘　　要：The magnetic activity of solar-type stars generally increases with stellar rotation rate. The increase, however, saturates for fast rotation. The Babcock-Leighton mechanism of stellar dynamos saturates as well when the mean tilt angle of active regions approaches ninety degrees. Saturation of magnetic activity may be a consequence of this property of the Babcock-Leighton mechanism. Stellar dynamo models with a tilt angle proportional to the rotation rate are constructed to probe this idea.Two versions of the model- treating the tilt angles globally and using Joy＇s law for its latitude dependence- are considered. Both models show a saturation of dynamogenerated magnetic flux at high rotation rates. The model with latitude-dependent tilt angles also shows a change in dynamo regime in the saturation region. The new regime combines a cyclic dynamo at low latitudes with an（almost） steady polar dynamo.The magnetic activity of solar-type stars generally increases with stellar rotation rate. The increase, however, saturates for fast rotation. The Babcock-Leighton mechanism of stellar dynamos saturates as well when the mean tilt angle of active regions approaches ninety degrees. Saturation of magnetic activity may be a consequence of this property of the Babcock-Leighton mechanism. Stellar dynamo models with a tilt angle proportional to the rotation rate are constructed to probe this idea.Two versions of the model- treating the tilt angles globally and using Joy＇s law for its latitude dependence- are considered. Both models show a saturation of dynamogenerated magnetic flux at high rotation rates. The model with latitude-dependent tilt angles also shows a change in dynamo regime in the saturation region. The new regime combines a cyclic dynamo at low latitudes with an（almost） steady polar dynamo.

关 键 词：saturation stellar latitude rotation rotating stars polar regime meridional consequence 

分 类 号：P152[天文地球—天文学] TM744[电气工程—电力系统及自动化]