太阳过渡区爆发事件的观测及理论研究进展  

Observational and Theoretical Studies on Explosive Events in the Solar Transition Region

作　　者：章敏[1] 夏利东[2] 黄正化[1] 

机构地区：[1]中国科学技术大学地球和空间科学学院,合肥230026 [2]山东大学威海分校空间科学与物理学院,威海264209

出　　处：《天文学进展》2010年第3期229-242,共14页Progress In Astronomy

基　　金：国家自然科学基金资助项目(40574064;40774080)

摘　　要：太阳过渡区爆发事件是过渡区重要的小尺度活动现象之一,常被过渡区的紫外和极紫外谱线观测到。典型的爆发事件的寿命为60～360 s,现象出现时谱线形状呈非高斯形,谱像两翼显示双向喷流结构,喷流速度大致在100 km·s^(-1),与色球局地阿尔芬速度相当。普遍认为其产生原因为小尺度快速磁重联。主要回顾了爆发事件的观测特征及其光谱学诊断方法,阐述了爆发事件的物理形成机制及与其他过渡区小尺度结构的联系,并讨论其在太阳风形成和日冕加热过程中对物质及能量输运的影响。最后对未来爆发事件的研究提出了展望。Explosive events are small-scale dynamic events often detected in the far and extreme ultraviolet（FUV/EUV） spectral lines of the Sun,which are emitted mainly by the solar transition region.They have a small spatial scale of about 1500 km and a short lifetime of about 60 s on average.As transient events and jets,they are characterized by non-Gaussian and broad profiles with an enhancement of emission in the blue/red wings resulting from a high velocity component. Typically,these bi-directional streams have an average line-of-sight velocity of 100 km·s^（-1）, which is comparable to the local Alfven velocity in the chromosphere.Explosive events tend to occur along the boundaries of the magnetic network and in cell regions,where weak mixed-polarity magnetic features are present.Because typical explosive events produce apparently bi-directional flows with high velocities,they have been suggested to be a consequence of small-scale magnetic reconnection.Sometimes,explosive events are also found to burst repeatedly in the same region, which may be caused by repetitive reconnection triggered by P-modes or transverse oscillations of the flux tubes.Although explosive events are best seen in typical transition-region lines,they can also be detected in spectral lines with a wide formation temperature ranging from about 1×10~4～5×10~5 K.When an explosive event can be seen in a chromospheric line（H I Ly 6,20 000 K）,a delay time of about 20～40 s in the response of the transition-region line （S IV,200 000 K） has been observed.However,there are almost no explosive events seen in coronal lines such as the Mg X line.Relationship between explosive events and other small-scale events observed in the transition region,such as blinkers and EUV spicules has also been investigated during the SOHO era.It is found that explosive events have the size and duration which are comparable to unit brightening events which may constitute blinkers.Nevertheless, statistical studies by some authors have suggested that explosive ev

关 键 词：太阳物理学 太阳过渡区 爆发事件 紫外辐射 

分 类 号：P182[天文地球—天文学]