太阳日冕加热事件的多波段分析

Multi-wavelength Analysis to Solar Corona Heating Events

随着大熊湖太阳天文台的1.6 m口径的新太阳望远镜(BBSO/NST)的成功运行,太阳观测已经进入了优于O.1″的高分辨率时代.这有助于详细分析单个曰冕加热事件,从而为日冕加热问题的最终解决提供原始的高分辨率的观测证据.利用NST所获得的在中性氦10830 A谱线、氧化钛7057 A谱线和H_α蓝翼(-0.7A)高分辨率成像观测数据,结合太阳动力学天文台上搭载的大气成像仪(SDO/AIA)和曰球磁场成像仪(SDO/HMI)同时观测到的极紫外和纵向磁场成像数据,分析了源自太阳米粒间通道的两个小的曰冕加热事件(磁环增亮)中的磁场演化.发现:这两个增亮磁环的足点都处于磁场中性线附近的一侧,一个磁环的足点伴随着一个小的纵向磁场单元的消失和两个米粒之间新形成的连接;在另一磁环的足点伴随着纵向磁场的微弱变化和一个米粒的破碎.据此,倾向于认为发生在太阳米粒之间底层大气的重联同时产生了高温和低温物质的外流.同时指出高分辨率和高偏振测量精度的光球磁场观测对于最终解决曰冕加热问题是至关重要的.

With the advent and successful running of the 1.6 meter aperture New Solar Telescope at Big Bear Solar Observatory（BBSO/NST）,solar observation has entered the era of 0.1 arc second.This permits us to carry out case studies for single coronal heating event,accumulating original high-resolution observational evidences for a final resolving of the coronal heating problem.By combining the high-resolution Helium 110830 A,TiO 7057 A,and H_α- 0.7 A imaging data from NST,and the satellite data from the Atmospheric Imaging Assembly（AIA） and Helioseismic and Magnetic Imager（HMI） on board the Solar Dynamics Observatory（SDO）,we analyze the evolution of magnetic field in the roots of two tiny dynamical events originating from the Sun＇s intergranular lanes as seen from Helium I 10830 A images.The two events caused subsequent brightening in the corona,but no obvious feature is found at H_α-0.7 A images.We find that the two events are rooted at one side of magnetic polarity inversion line.One event is apparently accompanied by the disappearance of a tiny magnetic element,while,in another event,weakening of a magnetic concentration area is found.Changes for granules are also found during the two events.The results suggest that the two heating events are caused by small-scale magnetic activities in intergranulax lanes driven by constant granule convection.It appears that ubiquitous small-scale magnetic activities produce outflow of cold matter as seen at 10830 A and hot matter as seen at extreme ultraviolet bands.