Some basic questions on helicity inferred from vector magnetograms  

作　　者：XU HaiQing GAO Yu ZHANG HongQi 

机构地区：[1]Key Laboratory of Solar Activity,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2009年第11期1749-1753,共5页中国科学：物理学、力学、天文学（英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos. 10611120338, 10473016, 10673016, 60673158, 10733020, and10978015);the National Basic Research Program of China (Grant No. 2006CB806301);the Important Directional Project of Chinese Academy of Sciences (Grant No. KLCX2-YW-T04)

摘　　要：This paper summarizes current helicity measurements in the solar active regions (ARs). There is a basic agreement with the "hemispheric sign rule (HSR)" of the current helicity among different vector magnetographs through two solar cycles, but there is a large dispersion of the fraction of ARs following the HSR. In our sample, there are 50%-78% ARs in solar cycle 22 and 44%-79% ARs in cycle 23 following the HSR. A variation is also found in the fraction of the ARs following the HSR between different instruments even when the same ARs are selected. The difference also exists for the same instrument when the selected ARs are different. There are some differences in the variation of HSR with solar cycle for the individual helicity parameter inferred from different instruments. Factors which influence the correlation of different data sets are analyzed.This paper summarizes current helicity measurements in the solar active regions (ARs). There is a basic agreement with the “hemispheric sign rule (HSR)” of the current helicity among different vector magnetographs through two solar cycles, but there is a large dispersion of the fraction of ARs following the HSR. In our sample, there are 50%–78% ARs in solar cycle 22 and 44%–79% ARs in cycle 23 following the HSR. A variation is also found in the fraction of the ARs following the HSR between different instruments even when the same ARs are selected. The difference also exists for the same instrument when the selected ARs are different. There are some differences in the variation of HSR with solar cycle for the individual helicity parameter inferred from different instruments. Factors which influence the correlation of different data sets are analyzed.

关 键 词：photosphere MAGNETIC field HELICITY SOLAR DYNAMO 

分 类 号：P182[天文地球—天文学]