A cancellation is thought to be a basic process of the photospheric magnetic field and plays an important role in magnetic flux budget and in various solar activities. There are two major theoretical scenarios for this phenomena, i.e. the "U-loop emergence" and the Omega-loop submergence models. It is important to clarify which is the dominant process during the cancellation for the estimation of the solar magnetic flux transport through the surface. We study the vector magnetic field and velocity structures around a quiet Sun cancellation by using the Solar Optical Telescope on board Hinode satellite. Transverse magnetic field connecting the canceling magnetic features and strong long-lasting Doppler red-shift signal are found. The transverse field is observed in the first spectropolarimetric observation after the occurrence of the cancellation while the red-shift clearly delayed to the cancellation by 20 minutes. These results indicate that the observed cancellation is an Omega-loop submergence.
Fine-scale explosive energy release at sites of prospective magnetic flux cancellation in the core of the solar active region observed by Hi-C 2.1, IRIS and SDO
Quantifying Properties of Photospheric Magnetic Cancellations in the Quiet Sun Internetwork
我们分析了瑞典1米太阳望远镜的分光偏振数据,以研究安静的太阳光球中小尺度磁抵消的物理特性。具体来说,我们看了完整的斯托克斯偏振配置文件沿Fe I 557.6 nm和Fe I 630.1 nm线测量的CRISP成像光谱偏振仪(CRISP)研究时间演变的视线(LOS)磁场在42.5分钟的安静的太阳演变。从这个磁图序列中,我们直观地识别出38个抵消事件。然后,我们使用另一种特征跟踪算法(YAFTA)来表征这些磁抵消的物理特性。我们发现,在每个事件中,磁通量的平均$1.6\times10^{16}$ Mx被抵消,平均抵消率为$3.8\times10^{14}$ Mx s $^{-1}$。推导出的抵消通量与强下行流有关,平均速度为$V_\mathrm{LOS}\approx1.1$ km s $^{-1}$。我们的研究结果表明,每个事件的平均寿命是$9.2$分钟,平均$44.8\%$的初始磁通被取消。我们对磁通量的估计提供了一个下限,因为所研究的磁抵消事件具有非常接近仪器噪声水平的磁场值。我们没有观察到水平磁场的取消网站,因此不能得出结论,事件是否相关的结构,可能会导致磁重联。
Direct Observations of Plasma Upflows and Condensation in a Catastrophically Cooling Solar Transition Region Loop
最小的观测证据存在的快速过渡区(TR)的冷环的存在下,上升流。这种现象的观测挑战了标准太阳大气加热模型的概念,以及它们对明亮TR发射的描述。使用{\it Hinode}上的{\it EUV成像光谱仪}(EIS),我们在冷却环路($\log T$\,$\le$\,6.0)的足点位置处观察到多个TR温度(5.8\,$\le$\,$\log T$ \,$\le$ 6.0)上的快速上升流($v_λ$\,$\le$ \,$-$ 10 km s $^{-1}$)。在冷回路通电之前,在足点位置观察到$+$\,5 km s $^{-1}$和$-$\,60 km s $^{-1}$的不对称流动。这些流动速度和模式与从{ \it Solar Dynamics Observatory}(SDO){ \it Helioseismic Magnetic Imager}(HMI)的视线磁象图得出的磁通量抵消(仅在上升流的位置)和日冕高度30%的质量通量同时发生。冷却回路的非平衡结构导致灾难性的冷却事件,随后的等离子体蒸发指示TR为加热部位。从磁通量的演变,我们得出结论,磁重联之间的足点和背景场是负责观察到的快速TR等离子体上升流。
Magnetar counterparts, kinematics and birth sites with HST and JWST
European Space Agency (ESA), European Space Research and Technology Centre (ESTEC)(欧洲航天局(ESA)欧洲空间研究与技术中心(ESTEC));Department of Astrophysics/IMAPP, Radboud University(拉德堡德大学天体物理学系/IMAPP);Department of Physics, University of Warwick(华威大学物理系);European Space Agency (ESA), European Space Astronomy Centre (ESAC)(欧洲航天局(ESA)欧洲空间天文中心(ESAC));Space Telescope Science Institute(太空望远镜科学研究所);Istituto Nazionale di Astrofisica (INAF) – Osservatorio Astronomico di Palermo(意大利国家天体物理研究所(INAF)- 巴勒莫天文台);Department of Physics, The George Washington University(乔治华盛顿大学物理系);GWU/Astronomy, Physics and Statistics Institute of Sciences (APSIS)(乔治华盛顿大学/天体物理学、物理学和统计学科学研究所(APSIS));School of Physics and Astronomy, University(物理与天文学学院,大学)
Catalog of fine-structured electron velocity distribution functions $-$ Part 1: Antiparallel magnetic-field reconnection (Geospace Environmental Modeling case)