YNAO OpenIR研究单元&专题: 太阳物理研究组http://ir.ynao.ac.cn:80/handle/114a53/392024-03-29T06:53:58Z2024-03-29T06:53:58ZCan the Parker Solar Probe Detect a CME-flare Current Sheet?陈雨豪刘忠Chen, PengfeiWebb, David F.Hao, Qi胡佳亮程冠冲梅志星叶景Wang, Qian林隽http://ir.ynao.ac.cn:80/handle/114a53/264762024-03-29T05:33:11Z2024-03-29T05:33:10Z题名: Can the Parker Solar Probe Detect a CME-flare Current Sheet?
作者: 陈雨豪; 刘忠; Chen, Pengfei; Webb, David F.; Hao, Qi; 胡佳亮; 程冠冲; 梅志星; 叶景; Wang, Qian; 林隽
摘要: A current sheet (CS) is the central structure in the disrupting magnetic configuration during solar eruptions. More than 90% of the free magnetic energy (the difference between the energy in the nonpotential magnetic field and that in the potential one) stored in the coronal magnetic field beforehand is converted into the heating and kinetic energy of the plasma, as well as accelerating charged particles, by magnetic reconnection occurring in the CS. However, the detailed physical properties and fine structures of the CS are still unknown, since there is no relevant information obtained via in situ detections. The Parker Solar Probe (PSP) may provide us with such information should it traverse a CS in an eruption. The perihelion of PSP's final orbit is located at about 10 solar radii from the center of the Sun, so it can observe the CS at a very close distance, or even traverse the CS, which would provide us with a unique opportunity to look into the fine properties and structures of the CS, helping to reveal the detailed physics of large-scale reconnection that would have been impossible before. We evaluate the probability that PSP can traverse a CS, and examine the orbit of a PSP-like spacecraft that has the highest probability to traverse a CS.2024-03-29T05:33:10ZThe Evolution of Photospheric Magnetic Fields at the Footpoints of Reconnected Structures in the Solar AtmosphereDing, TaoZhang, JunFang, Yue洪俊超毕以向永源http://ir.ynao.ac.cn:80/handle/114a53/264742024-03-29T05:33:03Z2024-03-29T05:33:03Z题名: The Evolution of Photospheric Magnetic Fields at the Footpoints of Reconnected Structures in the Solar Atmosphere
作者: Ding, Tao; Zhang, Jun; Fang, Yue; 洪俊超; 毕以; 向永源
摘要: Magnetic reconnection is believed to play an important role in the release and conversion of energy among magnetized plasma systems. So far, we have been unable to understand under what conditions magnetic reconnection can take place. Based on observations from the New Vacuum Solar Telescope and the Solar Dynamics Observatory (SDO), we study 16 magnetic reconnection events, and each event has a clear X-type configuration consisting of two sets of atmospheric structures. We focus on 38 footpoints that are relevant to these structures and can be clearly determined. By using SDO/Helioseismic and Magnetic Imager line-of-sight magnetograms, we track the field evolution of these footpoints. Prior to the occurrence of magnetic reconnection, the associated fields at the footpoints underwent convergence and shear motions, and thus became enhanced and complex. During the converging period, the rates of increase of the mean magnetic flux densities (MFDs) at these footpoints are 0.03-0.25 hr-1. While the unsigned mean MFDs are 70-300 G, magnetic reconnection in the solar atmosphere takes place. Subsequently, the photospheric fields of these footpoints diffuse and weaken, with rates of decrease of the MFDs from 0.03 to 0.18 hr-1. These results suggest that, due to the photospheric dynamical evolution at the footpoints, the footpoint MFDs increase from a small value to a large one, and the corresponding atmospheric magnetic fields become complicated and nonpotential; then reconnection happens and it releases the accumulated magnetic field energy. Our study supports the conjecture that magnetic reconnection releases free magnetic energy stored in the nonpotential fields.2024-03-29T05:33:03ZTwo-sided Loop Solar Jet Driven by the Eruption of a Small Filament in a Big Filament Channel杨家艳Chen, Hechao洪俊超杨波毕以http://ir.ynao.ac.cn:80/handle/114a53/264732024-03-29T05:33:03Z2024-03-29T05:33:01Z题名: Two-sided Loop Solar Jet Driven by the Eruption of a Small Filament in a Big Filament Channel
作者: 杨家艳; Chen, Hechao; 洪俊超; 杨波; 毕以
摘要: Similar to the cases of anemone jets, two-sided loop solar jets can also be produced by either flux emergence from the solar interior or small-scale filament eruptions. Using high-quality data from the Solar Dynamics Observatory, we have analyzed a two-sided loop solar jet triggered by the eruption of a small filament. The jet occurred in a pre-existing big filament channel. The detailed processes involved in the eruption of the small filament, the interaction between the erupted filament and the big filament channel, and the launch of the two-sided loop jet are presented. The observations further revealed notable asymmetry between the two branches of the jet spire: the northeastern branch is narrow and short, while the southern branch is wide and long and accompanied by discernible untwisting motions. We explored the unique appearance of the jet by employing the method of local potential field extrapolation to calculate the coronal magnetic field configuration around the jet. The photospheric magnetic flux below the small filament underwent cancellation for approximately 7 hr before the filament eruption, and the negative flux near the southern footpoint of the filament decreased by about 56% during this interval. Therefore, we propose that the primary photospheric driver of the filament eruption and the associated two-sided loop jet in this event is flux cancellation rather than flux emergence.2024-03-29T05:33:01ZExcitation of Quasiperiodic Fast-propagating Waves in the Early Stage of the Solar Eruption胡佳亮叶景陈雨豪梅志星汤泽浩林隽http://ir.ynao.ac.cn:80/handle/114a53/264692024-03-29T05:32:57Z2024-03-29T05:32:56Z题名: Excitation of Quasiperiodic Fast-propagating Waves in the Early Stage of the Solar Eruption
作者: 胡佳亮; 叶景; 陈雨豪; 梅志星; 汤泽浩; 林隽
摘要: We propose a mechanism for the excitation of large-scale quasiperiodic fast-propagating magnetoacoustic (QFP) waves observed on both sides of the coronal mass ejection. Through a series of numerical experiments, we successfully simulated the quasi-static evolution of the equilibrium locations of the magnetic flux rope in response to the change of the background magnetic field, as well as the consequent loss of the equilibrium that eventually gives rise to the eruption. During the eruption, we identified QFP waves propagating radially outward of the flux rope, and tracing their origin reveals that they result from the disturbance within the flux rope. Acting as an imperfect waveguide, the flux rope allows the internal disturbance to escape to the outside successively via its surface, invoking the observed QFP waves. Furthermore, we synthesized the images of QFP waves on the basis of the data given by our simulations and found consistency with observations. This indicates that the leakage of the disturbance outside the flux rope could be a reasonable mechanism for QFP waves.2024-03-29T05:32:56ZNumerical Simulation on the Leading Edge of Coronal Mass Ejection in the Near-Sun Region梅志星叶景李燕许杉杉陈雨豪胡佳亮http://ir.ynao.ac.cn:80/handle/114a53/264502024-03-29T05:32:23Z2024-03-29T05:32:23Z题名: Numerical Simulation on the Leading Edge of Coronal Mass Ejection in the Near-Sun Region
作者: 梅志星; 叶景; 李燕; 许杉杉; 陈雨豪; 胡佳亮
摘要: The coronal mass ejections (CMEs) observed by white-light coronagraphs, such as the Large Angle and Spectrometric Coronagraph (LASCO) C2/C3, commonly exhibit the three-part structure, with the bright leading edge as the outermost part. In this work, we extend previous work on the leading edge by performing a large-scale 3D magnetohydrodynamic numerical simulation on the evolution of an eruptive magnetic flux rope (MFR) in a near-Sun region based on a radially stretched calculation grid in spherical coordination and the incorporation of solar wind. In the early stage, the new simulation almost repeats the previous results, i.e., the expanding eruptive MFR and associated CME bubble interact with the ambient magnetic field, which leads to the appearance of the helical current ribbon/boundary (HCB) wrapping around the MFR. The HCB can be interpreted as a possible mechanism of the CME leading edge. Later, the CME bubble propagates self-consistently to a larger region beyond a few solar radii from the solar center, similar to the early stage of evolution. The continuous growth and propagation of the CME bubbles leading to the HCB can be traced across the entire near-Sun region. Furthermore, we can observe the HCB in the white-light synthetic images as a bright front feature in the large field of view of LASCO C2 and C3.2024-03-29T05:32:23Z弱磁场区复杂暗条的三维结构及其部分爆发的研究康凯锋http://ir.ynao.ac.cn:80/handle/114a53/264162024-03-26T06:35:05Z2024-03-26T06:24:38Z题名: 弱磁场区复杂暗条的三维结构及其部分爆发的研究
作者: 康凯锋
摘要: A solar filament (also called solar prominence)is composed of a magnetic structure that floats in the hot and tenuous corona and the partially ionized plasma, which is about 100 times denser/cooler than their coronal surroundings. The coronal mass ejections (CME) and solar flares are the main driver of the space weather and always believed to be closely associated with filament eruptions. However, so far, the reason why the cool and dense filament can exist in the hot and tenuous corona is still a question that has not been fully resolved. Magnetic fields are considered to be central to maintaining filament existence in the coronal surroundings. Therefore, measuring the magnetic field of filaments to obtain their three-dimensional (3D) magnetic structure is key to better understand their structure, evolution and eruption. Unfortunately, only on the photosphere can magnetic field be routinely measured and the magnetic field in the upper solar atmosphere is very difficult to measure directly. In the most cases, the 3D coronal magnetic field is obtained by extrapolating the measured photospheric magnetic field.Though the traditional magnetic field extrapolation methods can obtain the magnetic structures of the filaments that locate in the strong field region in the most cases, they always fail for the filaments in the weak field region. In this paper, by the regularized Biot-Savart laws method, we successfully constructed a 3D overall magnetic configuration for an large-scale, horse-shoe-like filament located in a decaying, diffuse and weak field. It is found that there are three regions with significantly different magnetic field strength within it, namely, the kernel region that possesses the strongest magnetic field, the outermost region that has the weakest field, and the middle region that has an intermediate field strength. At the same time, the model reveals a correspondence between the cold materials of filament and magnetic dips, namely, the colder component of the materials is prone to distribute in the magnetic dips. In addition, a new formation mechanism of barbs is confirmed, i.e., the barbs of the filament are a natural consequence of the deformation of a magnetic flux rope (MFR) and not anchored to the photosphere.Then, the process and mechanism of the filament eruption are further investigated in this paper. We found that before the eruption, the filament split into three branches with the same chirality as it, two low-lying branches and a high-lying branch. By analysing the splitting process in detail, we suggest that the pre-eruption splitting is induced by a reconnection between the magnetic field of MFR and newly emerging magnetic field. In the mean time, to the best of our knowledge, this is the first unambiguous observational evidence for the pre-eruption splitting of MFR induced by the reconnection between the magnetic field of MFR and newly emerging magnetic field. After the splitting, the filament erupted. And we find that the two low-lying parts survived the eruption, still located in the source region, while the high-lying part successfully escaped, producing a fast CME and a C1.2 flare, indicating that the filament experienced a parital eruption.However, the observations of the partial eruption presented here can be interpreted neither by the classical “double-decker filament” model nor the “partially-expelled-flux-rope” model. Therefore, the event provides new observational constraints on the construction of the new models for partial eruptions. At the same time, by analysing the kinematics of the process of the eruption and calculating the decay index of the background magnetic fields, we suggest that catastrophe (or torus instability) is the eruption mechanism of the filament.
摘要: 太阳暗条(也称日珥)由悬浮于高温、稀薄日冕大气中的磁场结构和部分电离等离子体构成,其密度/温度比周围日冕环境的高/低100倍。日冕物质抛射(CME)和耀斑是空间天气的重要驱动源,被认为和暗条爆发密切相关。但是,到目前为止,冷而密的暗条在热而薄的日冕中存在的原因,依然是个未完全解开的谜题。磁场被认为是维持暗条在日冕环境中存在的核心。因此,测量暗条的磁场以得到其三维磁场结构是理解暗条结构、演化和爆发的关键。然而,目前仅能常规测量到太阳光球的磁场,太阳上层大气的磁场测量则非常困难。在绝大多数情况下,三维日冕磁场是通过光球磁场的外推得到的。尽管常规的磁场外推方法多数情况下能较好地得到强场区暗条的磁场结构,但是对弱场区暗条则通常无能无力。本文首先利用正则化毕奥-萨伐尔定律为处于衰退且弥散的弱磁场区的一个大尺度马蹄形暗条构建出了整体三维磁场结构。发现暗条内部存在三个磁场强度明显不同的区域,分别是:磁场最强的核心区、磁场最弱的外侧区以及磁场强度介于前两者之间的中间区。同时,该模型还揭示了暗条冷物质分布和磁凹陷之间的对应关系,即,暗条中较冷的物质成分更倾向于分布在磁凹陷结构中。此外,还确认了暗条倒钩的一种形成机制,认为暗条倒钩是由磁绳的形变产生的,并不一定扎根于光球。然后,本文进一步研究了该暗条的爆发过程和发生机制。我们发现,在爆发前,该暗条发生了分裂,并且分裂成了手性相同的3部分。其中,两部分位于低处,一部分位于高处。通过对分裂过程的详细分析,我们认为该暗条磁绳结构的爆发前分裂是由磁绳磁场和新浮磁场之间的重联导致的。同时,就目前所知,这也是第一次明确观测到由磁绳磁场和新浮磁场之间的重联引起的爆发前磁绳分裂。在完成分裂后,该暗条发生了爆发。并且我们发现低处的两部分在爆发中存活了下来,依然留在源区域,而高处的那部分则成功爆发掉了,并产生了一个快速CME和一个C1.2级耀斑。这表明,该暗条经历了一次部分爆发。但是,这里所呈现的部分爆发观测,并不能被经典的“双层暗条”模型或“部分抛射磁绳”模型所解释。因此,该事件为新的部分爆发模型的构建提供了新的观测限制。同时,通过对爆发过程的运动学特征进行分析,以及计算背景磁场的衰减因子,我们认为灾变(或环不稳定性)是该暗条的爆发机制。2024-03-26T06:24:38Z类埃勒曼炸弹事件中的磁重联和加热机制的磁流体力学模拟研究刘明玉http://ir.ynao.ac.cn:80/handle/114a53/263972024-03-26T06:35:05Z2024-03-26T06:24:25Z题名: 类埃勒曼炸弹事件中的磁重联和加热机制的磁流体力学模拟研究
作者: 刘明玉
摘要: The Ellerman Bomb (EBs) is a kind of small scale reconnection events, which are ubiquitously formed in the upper photosphere or the lower chromosphere. The low temperature ($<10,000$\,K) and high density ($\sim 10^{19}-10^{22}$) plasma there make the magnetic reconnection process strongly influenced by the partially ionized effects and the radiative cooling. This work studied the high $\beta$ magnetic reconnection near the solar temperature minimum region (TMR) based on high-resolution 2.5D magnetohydrodynamics (MHD) simulations. The time-dependent ionization degree of hydrogen and helium are included to realize more realistic diffusivities, viscosity and radiative cooling in simulations. Numerical results show that the reconnection rate is smaller than 0.01 and decreases with time during the early quasi-steady stage, then sharply increases to a value above 0.05 in the later stage as the tearing model (plasmoid) instability takes place. Both the large value of $\eta_{en}$ (magnetic diffusion caused by the electron-neutral collision) and the plasmoid instability contribute to the fast magnetic reconnection in the EB-like event. The interactions and the coalescence of plasmoids strongly enhance the local compression heating effect, which becomes the dominant mechanism for heating in EBs after plasmoid instability appears. However, the Joule heating contributed by $\eta_{en}$ can play a major role to heat plasmas when the magnetic reconnection in EBs is during the quasi-steady stage with smaller temperature increases. The results also show that the radiative cooling effect suppresses the temperature increase to a reasonable range, increases the reconnection rate and the generation of thermal energy.
摘要: 埃勒曼炸弹(Ellerman Bombs,EBs)是一种普遍形成于高光球低色球的小尺度磁重联事件。此区域为低温($<10,000$\,K)和高密度 ($\sim 10^{19}-10^{22}$)的等离子体环境,将使磁重联过程强烈地受到部分电离和辐射冷却的影响。本工作基于高数值分辨率的2.5维磁流体动力学(2.5D MHD)模拟,研究了太阳温度极小区(TMR)附近的高等离子体$\beta$的磁重联过程。为了在模拟中实现更真实的扩散系数、粘度和辐射冷却,我们加入氢和氦的随时间演化的温度依赖的电离度。数值计算结果表明,在初期准稳态演化阶段,重联率小于0.01,且随着时间的演化而减小。随后,撕裂模(等离子体团)不稳定性磁重联发生,重联率急剧增大到0.05。在类EBs事件中,较大的$\eta_{en}$(电子-中性粒子碰撞引起的磁扩散)和等离子体团不稳定性都有助于快磁重联。等离子体团之间的相互作用和碰撞合并极大地增强了局部压缩加热效应,使得压缩加热成为等离子体团不稳定性出现后EBs加热的主要机制。然而,当EBs中的磁重联处于温度升高较小的准稳态演化阶段,由$\eta_{en}$所贡献的焦耳加热对等离子体的加热起重要作用。模拟结果还表明,辐射冷却效应将温度升高抑制在与观测相符的合理范围内,同时增加了重联率和热能的产生。2024-03-26T06:24:25Z一种开合观测屋顶王晶星张涛李燕林隽宋腾飞张雪飞http://ir.ynao.ac.cn:80/handle/114a53/263812024-03-26T05:59:25Z2024-03-26T05:59:25Z题名: 一种开合观测屋顶
作者: 王晶星; 张涛; 李燕; 林隽; 宋腾飞; 张雪飞
摘要: 本实用新型公开了一种开合观测屋顶,包括:墙体、开合屋顶框架、开合屋顶、驱动装置和控制装置,所述墙体包括第一墙体和第二墙体,所述第一墙体的顶部设置有固定屋顶,所述第二墙体的顶部为开口设计,所述开合屋顶框架固定设置于所述墙体外围,所述开合屋顶可活动套设于所述开合屋顶框架上,并可相对所述开合屋顶框架沿第一方向来回滑动,所述驱动装置用于驱动所述开合屋顶沿所述第一方向来回滑动,所述控制装置与所述驱动装置电连接,用于控制所述驱动装置动作,以使所述开合屋顶打开或关闭所述第二墙体顶部的开口。本实用新型通过上述开合屋顶框架和开合屋顶的巧妙设计,使得本申请的开合观测屋顶结构更加牢固,操作更加方便、灵敏。2024-03-26T05:59:25Z一种精跟踪相机固定装置王晶星张涛李燕林隽宋腾飞张雪飞http://ir.ynao.ac.cn:80/handle/114a53/263802024-03-26T05:59:24Z2024-03-26T05:59:23Z题名: 一种精跟踪相机固定装置
作者: 王晶星; 张涛; 李燕; 林隽; 宋腾飞; 张雪飞
摘要: 本实用新型提供一种精跟踪相机固定装置,包括:固定架、固定板和第一螺栓,所述固定架包括底板和固定件,所述底板设置在所述固定板上,所述固定件设置在所述底板上,且所述底板上开设有若干第一螺孔,所述固定板上开设有若干腰孔,所述腰孔与所述第一螺孔对应设置,且所述腰孔设置在同一同心圆上;所述第一螺栓可贯穿设置于所述腰孔和所述第一螺孔,用于将所述底板固定安装于所述固定板上,且所述底板能够以所述同心圆的圆心为中心相对所述固定板旋转,所述同心圆的圆心为所述底板的旋转中心。本实用新型通过方位调节组件和俯仰调节组件的巧妙设计,使得精跟踪相机的固定安装更方便、调节精度更高。2024-03-26T05:59:23ZDifferential Rotation for Different-sized Sunspot Groups Early Observed by the OGAUCWan M(万苗)Gao PX(高朋鑫)Zeng, Shu-GuangDeng LH(邓林华)http://ir.ynao.ac.cn:80/handle/114a53/263502023-11-06T08:37:04Z2023-10-30T06:20:30Z题名: Differential Rotation for Different-sized Sunspot Groups Early Observed by the OGAUC
作者: Wan M(万苗); Gao PX(高朋鑫); Zeng, Shu-Guang; Deng LH(邓林华)
摘要: <p>Solar differential rotation is an important ingredient of the solar dynamo model, not only because the solar rotation profile is one of the key inputs in a solar dynamo model, but also because it imposes constraints for the solar dynamo model. In this study, we use the sunspot group catalog published by the Coimbra Astronomical Observatory for the period 1929-1941 to analyze solar rotation profiles of different-sized sunspot groups and the dependence of their annual average of the absolute latitude and annual average rotation rate on the solar cycle. The following main results are obtained: (1) smaller sunspot groups (with an area <100 millionths of the solar hemisphere (msh)) rotate faster than larger ones (with an area >500 msh); (2) different-sized sunspot groups drift toward the equator at different velocities of latitudinal drift, reflecting that they are rooted at different anchoring depths; (3) the rotation rate reaches a maximum during the minimum of the solar cycle, which seems to be independent of the size of sunspot groups. The possible mechanisms for the above results are discussed, and we infer that the differences may be due to the different anchoring depths at which flux tubes of different-sized sunspot groups are rooted, their different ages, and the different ways in which sunspot group coordinates are determined.</p>2023-10-30T06:20:30Z