Reversal magnetic chirality of solar active regions and a possible dynamo model

Abstract

The transfer of magnetic chirality in solar active regions is related to the emerging magnetic flux ropes generated in the subatmosphere. This analysis has been presented based on the calculation of the injection of magnetic helicity at the solar surface. As the long-term evolution of the accumulated magnetic helicity is followed, it is found that the transfer of reversal magnetic helicity of active regions is a complex process, and is not monotonic with the same sign. It is found that the dominant contribution of helicity occurs mainly in the fast-developing stage of active regions.By considering the hemispheric trends of magnetic helicity, it is proposed that the reversal helicity in solar active regions has two possible causes: local generation in the convection zone, and trans-equatorial processes in the subatmosphere. In addition to the mirror-symmetrical reverse of twisted magnetic field in the convection zone, the possibility of a trans-equatorial process is discussed in this paper.

空间天气驱动源—太阳风暴研究

“…Yang 和 Zhang [238] 研究了磁场螺度从太阳活动区长期的输入, 他们发 现南北半球的大尺度的磁螺度流在 2001~2005 年显 示出同一符号. Zhang [239] 认为太阳活动区的螺度符号 的反转有两个可能的原因, 一是在对流区局地产生; 二是太阳大气底部的跨赤道的过程. Hao 和 Zhang [240] 用 Hinode 卫星矢量磁场观测数据研究了太阳第 23 活 动周下降相和第 24 活动周上升相的 64 个活动区的磁 螺度演变规律, 发现第 24 周上升相中的 34 个活动区 的磁螺度分布服从半球演变符号规则, 第 23 周下降 相中的 30 个活动区则不服从上述符号规则.…”