Twisted Coronal Mass Ejection on 4 August 2011
-
摘要: 利用多卫星多波段的综合观测数据,通过追踪光球表面等离子体速度分析计算了耀斑爆发前后磁螺度的变化,发现耀斑爆发前活动区中光球表面存在强的水平剪切运动,活动区磁螺度的注入主要由这种剪切运动所产生;使用CESE-MHD-NLFFF重建了耀斑爆发前后活动区的磁场位形,推测出耀斑过程中存在磁绳结构的抛射.基于这些分析,给出了这一螺旋状抛射结构的形成机制:爆发前暗条西侧足点的持续剪切运动驱动磁通量绳增加扭转,高度扭缠的通量绳与东侧足点附近的开放磁力线重联并与东侧足点断开,进而向外抛出并伴随解螺旋运动.另外,利用1AU处WIND卫星的观测数据在对应的行星际日冕物质抛射中找到典型磁云的观测特征.这表明除了传统上双足点均在太阳表面的磁云模型,这种单足点固定于太阳表面的磁通量绳爆发图景同样可能在行星系际空间形成磁云结构.研究结果对进一步认识磁云结构具有重要意义.Abstract: On 4 August 2011, a GOES M9.3 flare with a fast coronal mass ejection was erupted from solar active region NOAA AR11261. After the flare, a rotating structure is observed by STEREO, in which the rotating motion lasted about 4 hours. The magnetic helicity flux associated with the flare was calculated based on the SDO/HMI vector magnetograms by tracking the plasma velocity of the photosphere. It is found that the photospheric shear and twist motion contribute significantly to the magnetic helicity injection before the flare. The coronal magnetic fields were extrapolated using the CESE-MHD-NLFFF code, which shows that twisted magnetic flux rope exists before the flare and disappears after the flare. With these analyses, a scenario for the formation and evolution of this eruption is suggested as follows. The rotation of the foot point on the west side of the eruption filament twisted the magnetic flux rope, and the highly twisted structure became unstable and erupted. During the eruption, it reconnected with open magnetic field lines near one leg, and a long duration of untwisting movement followed the eruption. Interestingly, the observations of WIND satellites at 1AU show characteristics of typical magnetic clouds in the corresponding interplanetary coronal mass ejections of this eruption, which indicates that a magnetic cloud might be a flux rope with one leg anchored on the Sun, and it is not previously considered.
-
Key words:
- Flare /
- Coronal Mass Ejection (CME) /
- Magnetic helicity /
- Eruption model
-
[1] RUST D M. The helical flux rope structure of solar filaments[J]. Adv. Space Res., 2003, 32(10):1895-1903 [2] GILBERT H R, ALEXANDER D, LIU R. Filament kinking and its implications for eruption and reformation[J]. Solar Phys., 2007, 245(2):287-309 [3] CHENG X, GUO Y, DING M D. Origin and structures of solar eruptions I:magnetic flux rope[J]. Sci. China-Earth Sci., 2017, 60(8):1383-407 [4] STEINER O, FRANZ M, GONZALEZ N B, et al. Detection of vortex tubes in solar granulation from observations with sunrise[J]. Astrophys. J. Lett., 2010, 723(2):180-184 [5] WEDEMEYER-BOHM S, VAN DER VOORT L R. Small-scale swirl events in the quiet sun chromosphere[J]. Astron. Astrophys., 2009, 507(1):9-12 [6] MOORE R L, STERLING A C, FALCONER D A. Magnetic untwisting in solar jets that go into the outer corona in polar coronal holes[J]. Astrophys. J., 2015, 806(1):11 [7] CHEN H D, ZHANG J, MA S L. The kinematics of an untwisting solar jet in a polar coronal hole observed by SDO/AIA[J]. Res. Astron. Astrophys., 2012, 12(5):573-583 [8] GUO Y, CHENG X, DING M D. Origin and structures of solar eruptions Ⅱ:magnetic modeling[J]. Sci. China-Earth Sci., 2017, 60(8):1408-1439 [9] DEMOULIN P. Recent theoretical and observational developments in magnetic helicity studies[J]. Adv. Space Res., 2007, 39(11):1674-1693 [10] NINDOS A, ANDREWS M D. The association of big flares and coronal mass ejections:what is the role of magnetic helicity[J]. Astrophys. J., 2004, 616(2):175-178 [11] DOMINGO V, FLECK B, POLAND A I. The solar and heliospheric observatory[J]. Space Sci. Rev., 1995, 72(1-2):81-84 [12] RUSSELL C T. The STEREO Mission[M]. New York:Springer-Verlag, 2008 [13] PESNELL W D, THOMPSON B, CHAMBERLIN P C. The Solar dynamics observatory[M]. New York:Springer, 2011:3-15 [14] BOBRA M G, SUN X, HOEKSEMA J T, et al. The Helioseismic and Magnetic Imager (HMI) vector magnetic field pipeline:SHARPs-Space-weather HMI Active Region Patches[J]. Solar Phys., 2014, 289(9):3549-3578 [15] BERGER M A, FIELD G B. The topological properties of magnetic helicity[J]. J. Fluid Mech., 2006, 147(1):133 [16] BERGER M A. Magnetic helicity in a periodic domain[J]. J. Geophys. Res. Space Phys., 1997, 102(A2):2637-2644 [17] SCHUCK P W. Tracking vector magnetograms with the magnetic induction equation[J]. Astrophys. J., 2008, 683(2):1134-1152 [18] ADAMS J C. Mudpack-2:multigrid software for approximating elliptic partial-differential equations on uniform grids with any resolution[J]. Appl. Math. Comput., 1993, 53(2-3):235-249 [19] JIANG C W, FENG X S. Extrapolation of the solar coronal magnetic field from SDO/HMI magnetogram by a CESE-MHD-NLFFF code[J]. Astrophys. J., 2013, 769(2):144 [20] JIANG C, WU S T, FENG X, et al. Formation and eruption of an active region sigmoid I. A study by nonlinear force-free field modeling[J]. Astrophys. J., 2013, 780(1):55 [21] JIANG C W, FENG X S, ZHANG J A, et al. AMR simulations of magnetohydrodynamic problems by the CESE method in curvilinear coordinates[J]. Solar Phys., 2010, 267(2):463-491 [22] JIANG C W, FENG X S. Preprocessing the photospheric vector magnetograms for an NLFFF extrapolation using a potential-field model and an optimization method[J]. Solar Phys., 2014, 289(1):63-77 [23] RICHARDSON I G, CANE H V. Near-Earth interplanetary coronal mass ejections during solar cycle 23(1996-2009):catalog and summary of properties[J]. Solar Phys., 2010, 264(1):189-237 [24] ZURBUCHEN T H, RICHARDSON I G. In-situ solar wind and magnetic field signatures of interplanetary coronal mass ejections[J]. Space Sci. Rev., 2006, 123(1/2/3):31-43 [25] BURLAGA, LEONARD F E. Magnetic clouds. Physics of the Inner Heliosphere Ⅱ[M]. Berlin:Springer, 1991:1-22 [26] ZHANG J, HESS P, POOMVISES W. A comparative study of coronal mass ejections with and without magnetic cloud structure near the Earth:are all interplanetary CMEs flux ropes[J]. Solar Phys., 2013, 284(1):89-104 [27] DE PONTIEU B, LEMEN J, KUSHNER G, et al. The Interface Region Imaging Spectrograph (IRIS)[J]. Solar Phys., 2014, 289(7):2733-2779 [28] JIANG C, WU S T, FENG X, et al. Data-driven magnetohydrodynamic modelling of a flux-emerging active region leading to solar eruption[J]. Nat. Commun., 2016, 7:11522
点击查看大图
计量
- 文章访问数: 919
- HTML全文浏览量: 121
- PDF下载量: 52
- 被引次数: 0