Are Solar Active Regions Born with Neutralized Currents?  

作　　者：Aiying Duan Yaoyu Xing Chaowei Jiang 

机构地区：[1]Planetary Environmental and Astrobiological Research Laboratory(PEARL),School of Atmospheric Sciences,Sun Yat-sen University,Zhuhai 519000,China [2]Yunnan Key Laboratory of the Solar Physics and Space Science,Kunming 650216,China [3]Key Laboratory of Tropical Atmosphere-Ocean System,Sun Yat-sen University,Ministry of Education,Zhuhai 519000,China [4]Institute of Space Science and Applied Technology,Harbin Institute of Technology,Shenzhen 518055,China

出　　处：《Research in Astronomy and Astrophysics》2024年第7期79-88,共10页天文和天体物理学研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(NSFC)U2031108;Yunnan Key Laboratory of Solar Physics and Space Science under the number YNSPCC202213。

摘　　要：Solar active regions(ARs)are formed by the emergence of current-carrying magnetic flux tubes from below the photosphere.Although for an isolated flux tube the direct and return currents flowing along the tube should balance with each other,it remains controversial whether such a neutralization of currents is also maintained during the emergence process.Here we present a systematic survey of the degrees of the current neutralization in a large sample of flux-emerging ARs which appeared on the solar disk around the central meridian from 2010 to 2022.The vector magnetograms taken by Helioseismic and Magnetic Imager onboard Solar Dynamic Observatory are employed to calculate the distributions of the vertical current density at the photosphere.Focusing on the main phase of flux emergence,i.e.,the phase in which the total unsigned magnetic flux is continuously increased,we statistically examined the ratios of direct to return currents in all the ARs.Such a large-sample statistical study suggests that most of the ARs were born with currents close to neutralization.The degree of current neutralization seems to be not affected by the active-region size,the active-region growing rate,and the total unsigned current.The only correlation of significance as found is that the stronger the magnetic field nonpotentiality is,the further the AR deviates from current neutrality,which supports previous event studies that eruption-productive ARs often have non-neutralized currents.

关 键 词：SUN magnetic fields-Sun flares-Sun corona-Sun coronal mass ejections(CMEs) 

分 类 号：P182.9[天文地球—天文学]